sustainability

Article Identifying, Examining, and Planning Areas Protected from Light Pollution. The Case Study of Planning the First National Dark Sky Park in Greece

Andreas Papalambrou 1,* and Lambros T. Doulos 1,2

1 School of Applied Arts, Hellenic Open University, Parodos Aristotelous 18, 26335 Patras, Greece; [email protected] 2 Lighting Laboratory, School of Electrical and Computer Engineering, National Technical University of Athens, Zografou, 15780 Athens, Greece * Correspondence: [email protected]



Received: 30 September 2019; Accepted: 22 October 2019; Published: 26 October 2019


Abstract: Light pollution is a type of pollution that climaxes in cities and occurs increasingly away from them, due to the increase of artificial lighting and inappropriate lighting design (selection of luminaires, aiming, illuminance/luminance levels, and spectral characteristics). Increasingly, light pollution also affects the countryside due to local lighting but also distant lighting propagating from urban areas. This has a significant impact on ecosystems and astronomical observing sites. This work analyzes the main facts about light pollution (causes, impact, and solutions) and studies the methods, parameters, and special requirements for planning of light pollution protected areas. This dark sky park planning methodology is implemented as a case study in mount Parnon which has been selected due to its significance as a Natura 2000 protected area and because it is Greece’s most popular astronomical observing site. Mount Parnon is located close to two major cities as well as significant highways, however the site itself remains dark due to its sparse population. Planning a dark sky park involves a complete study of facts regarding the specific site. Existing lighting installations are surveyed in detail by recording types of luminaires and lamps and recording their positions in a map. Lighting illuminance levels are measured by photometers and spectra are analyzed using a spectrometer. Sky brightness levels measurements are performed using specialized photometers and light pollution origins are traced using wide-field photography. Finally, a proposal is made for a dark sky park scheme suited to the specific case of the site.

Keywords: astronomy; dark sky parks; environment; exterior lighting; light pollution; lighting; road lighting

1. Introduction In recent years there has been a strong effort for making lighting design [1–4] and corresponding lighting systems [5–8] sustainable and environmentally friendly [9] either by selecting efficient luminaires [10,11], lighting controls [12–15], or embodying more efficient lighting design [16–18] or daylight [19–23]. The importance of avoiding light pollution (LP) has gained interest in technical reports [24,25] and expert discussions [26] only in the last few years. Light pollution can be defined as the presence of excess, poorly directed, and unnecessary artificial lighting at night which in the natural environment crosses the boundary of fulfilling basic lighting needs and may become obtrusive or harmful. In its most visible form, light pollution appears as skyglow which is defined as the artificial diffuse luminance of the night sky [27]. Light pollution also appears in the form of glare, light trespass, and over-illumination [28]. Light pollution causes can be seen from a cultural as well as a technical

Sustainability 2019, 11, 5963; doi:10.3390/su11215963 www.mdpi.com/journal/sustainability Sustainability 2019, 11, 5963 2 of 24 aspect. Culturally, light pollution appeared as a consequence of urbanization and industrialization that took place in the 20th century [29]. Advances in lighting and the wide availability of electricity made electrical lighting ubiquitous, improved the quality of life for households, and made people seek more and more light while a significant industry was built around lighting which involved lighting companies as well as utility companies. Lack of awareness about potential adverse effects, low electricity prices, in combination with increased use of lighting for reasons other than fulfilling basic illumination needs, led to a type of illumination race that brought more light and higher illumination levels everywhere. Technically, light pollution owes its significant expansion to lighting malpractices including luminaire shielding, aiming, and maintenance. Light pollution would not have appeared in the levels we have today if simple technical requirements were enforced early in the quick expansion of artificial lighting. Light pollution is most often considered to originate in the late 1960s. Before that, although the potentially harmful effects of artificial lighting were known since the beginning of the 20th century, the amount of exterior lighting did not account for a significant threat in all but a handful of cities. Increased urbanization combined with low electricity prices led to the continuous increase of outdoor lighting. In the first few decades since then, until the 1980s, light pollution did not break out as a significant problem. In the 1980s light pollution started to be recognized as a problem due to the increasing disturbance of astronomical observatories. It was at this time that efforts to counteract it first started. Light pollution continued to increase steadily until recent years when discoveries of its effect on human health gave it wider news coverage and led to its increased perception as a complex problem. Currently, the most important challenge regarding light pollution is the introduction of light-emitting diode (LED) lighting and its impact on light pollution due to the cooler spectral characteristics of typical LEDs. The most prominent international effort to counteract light pollution is that conducted by the International Dark-Sky Association (IDA) [30]. Since its establishment in 1988, the IDA has led the effort around the world to promote light pollution awareness, lighting ordinances, and specific area protection. One of the most prominent efforts of the IDA has been the international Dark-Sky Places program [31]. This program recognizes protected areas as dark sky places based on criteria such as their importance for astronomy or the ecosystems, their outreach programs and activities. The international Dark-Sky Places program was founded in 2001 and as of July 2019 there are just over 100 certified places globally. The Dark-Sky Places program has had a significant impact in placing LP on the agenda globally and has acted as a flagship example that LP can be reversible if authorities are convinced to act. In order to protect sites of significant ecosystems, natural beauty, or astronomical interest, but also to continue its influence as a flagship example, it is important that light pollution reduction is included as a top priority of national parks, protected ecosystem areas, and astronomical observatories as well as public policy and ordinances. This will also present considerable economical gains due to the decrease of energy waste that light pollution brings as well as the reversal of human and animal health impacts that have been revealed in recent years [32–35]. Light pollution levels can be determined by the night sky brightness and there are several methods for the corresponding measurements [36]. There are several types of measuring equipment, from a typical sky quality meter (SQM) [37] to new types of photometers [38,39]. Except for SQM measurements, citizens’ observations could be valuable [40] as long as there is a consistence to their observations [41]. The scope of this paper is to identify the most appropriate area in Greece to be nominated as a dark sky place and perform a preliminary study on its suitability. A methodology is presented and applied to the region of the mount Parnon area in the Peloponnese. This methodology includes a lighting inventory which was created by surveying luminaires, sources intensity, type and spectrum in the villages surrounding the astronomical site as well as light pollution measurements [36,42–44] and assessment of socio-economic and environmental factors. Sustainability 2019, 11, 5963 3 of 24

2. Materials and Methods

2.1. Overview In Figure1 we present the overview of the methodology that was followed in order to select and assess the area. In order to plan for a protected area, it is necessary to survey as many parameters as Sustainability 2019, 11, x FOR PEER REVIEW 3 of 24 possible regarding geography, the condition of the night sky as well as the lighting installations of the possiblearea. The regarding most important geography, parameters the condition that were of the surveyed night sky and as their well results as the lighting are as follows: installations of the area.Lighting The most inventory important survey parameters that were surveyed and their results are as follows: • • IntensityLighting inve andntory spectrum survey characteristics • • LightIntensity pollution and spectrum assessment characteristics • • AssessmentLight pollution of various assessment socio-economic and environmental factors • • Assessment of various socio-economic and environmental factors The lighting inventory survey included the following parameters: The lighting inventory survey included the following parameters: Photographs of the most common luminaires • Photographs of the most common luminaires Light intensity measurements • Light intensity measurements Light source type • Light source type Geometrical characteristics of the lighting installations (height of luminaires, inclination, etc.) • Geometrical characteristics of the lighting installations (height of luminaires, inclination, etc.) Brief description of light distribution • Brief description of light distribution

Figure 1. Diagram of the methodology. Figure 1. Diagram of the methodology. 2.2. Selection of the Protected Areas 2.2. Selection of the Protected Areas In the early 1990s, the European Union (EU) habitats directive 92/43 [45] aimed to confront the increasingIn the threatearly 1990s, of extinction the European for many Union species (EU) of habitats flora and directive fauna. 92/43 It was [45] later aimed incorporated to confront into the increasingGreece’s national threat of legislation extinction by for the many Joint Ministerialspecies of Decisionflora and 33318fauna./3028 It was/1998. later The incorporated main aim of into the Greece’sDirective national is to promote legislation the maintenance by the Joint orMinisterial restoration Decision of biodiversity, 33318/3028/1998. taking account The main of economic,aim of the Directivesocial, cultural, is to promote and regional the maintenance requirements. or restorat As a mainion of part biodiversity, of the conservation taking account effort, of a Europeaneconomic, social,ecological cultural, network and of regional protected requirements. sites was created As a and ma namedin part Naturaof the conservation 2000. This protection effort, a status European had ecologicalno association network with of light protected pollution sites at was the created time. Greece and named included Natura as part 2000. of This the networkprotection 241 status sites had of nocommunity association importance with light (SCI) pollution according at the to time. the EU Greece Directive included 92/43 andas part declared of the 202 network special 241 protected sites of communityareas (SPAs) importance according to(SCI) EU according Directive to 79 /the409. EU A Directive map of the 92/43 areas and of declared Greece that202 formspecial part protected of the areasNatura (SPAs) 2000 networkaccording appears to EU inDirective Figure2 a79/409. [ 46]. GreenA map areas of the represent areas of areas Greece of protectedthat form status.part of It the is Natura 2000 network appears in Figure 2a [46]. Green areas represent areas of protected status. It is notable that a large percentage of the land in Greece is under protection which makes Greece an important protection zone. Sustainability 2019, 11, 5963 4 of 24 notable that a large percentage of the land in Greece is under protection which makes Greece an Sustainabilityimportant 2019 protection, 11, x FOR zone. PEER REVIEW 4 of 24

(a) (b)

FigureFigure 2. 2. (a()a Natura) Natura 2000 2000 protected protected areas areas in Greece in Greece [45,46] [45 ,and46] and(b) light (b) lightpollution pollution map of map Greece of Greece based onbased data on from data the from 2016 the atlas 2016 [47] atlas and [47 ]visualization and visualization by light by lightpollution pollution information information website website [48]. [The48]. examinedThe examined area areais within is within the red the square. red square.

ToTo perform perform a general overview of light pollution in Greece, the data from the 2016 light pollution atlasatlas were were used used [47]. [47]. The The map map (Figure 22b)b) showsshows significantsignificant lightlight pollutionpollution areasareas extendingextending tenstens ofof kilometerskilometers around around the the two two major cities (Athens, Thessaloniki)Thessaloniki) as well as significantsignificant lightlight pollutionpollution areasareas around around other other large large cities (Patra, Volos, Larisa, etc.).etc.). It is also evident that light pollution followsfollows thethe path path of of major highways (Athens–Lamia, Lami Lamia–Thessaloniki,a–Thessaloniki, Olympia and Moreas highways). TheThe most most significant significant light pollution gaps identified identified in the map (evident by darker-bluedarker-blue color)color) werewere foundfound in in the the following following areas: areas: Parts of central and southern Peloponnese around the mountains Helmos and Parnon •• Parts of central and southern Peloponnese around the mountains Helmos and Parnon • Parts of central Greece around Agrafa mountains • Parts of central Greece around Agrafa mountains • Parts of Western Macedonia around Grammos mountain. • Parts of Western Macedonia around Grammos mountain. • Parts of Southern Crete • Parts of Southern Crete ItIt is is evident thatthat darkdark skies skies in in Greece Greece are are mostly mostly found found in significantin significant mountain mountain ranges. ranges. This This is due is dueto the to factthe fact that that mountains mountains are sparselyare sparsely populated, populated, due todue the to lack the oflack major of major lighted lighted roads roads and less and light less lightpropagation propagation in mountainous in mountainous terrain. terrain. GreeceGreece is is home home to to a avery very active active amateur amateur astronomy astronomy community community which which has hasa very a very significant significant role inrole science in science outreach. outreach. The Thecommunity community also also forms forms a link a link between between the the scientific scientific community community and thethe public.public. Greece Greece has has more more than than 20 20 amateur amateur astronomy astronomy cl clubs,ubs, as as well well as as individu individualal amateur amateur astronomers, astronomers, whowho typically visit light pollution-free areas in orderorder toto observeobserve usingusing theirtheir telescopes.telescopes. AA limitedlimited numbernumber of of these these areas areas have have been been selected selected due due to to th theireir dark dark skies, skies, easy easy access, access, and and natural natural beauty, beauty, as sitesas sites of the of the annual annual amateur amateur astronomy astronomy gathering. gathering. In In total, total, 12 12 annual annual amateur amateur astronomy astronomy gatherings havehave been been organized organized as as of of 2018 in various places places,, but two sites stand out becausebecause theythey havehave beenbeen repeatedlyrepeatedly selected selected for for their their dark dark skies: skies: Parnon Mountain in the Peloponnese •• Parnon Mountain in the Peloponnese • Filippaioi area in Western Macedonia • Filippaioi area in Western Macedonia A place of both significant natural and astronomical importance, mount Parnon was chosen as the A place of both significant natural and astronomical importance, mount Parnon was chosen as proposed area for the first International Dark Sky Park in Greece. the proposed area for the first International Dark Sky Park in Greece.

2.3. Case Studies of Mount Parnon Area Sustainability 2019, 11, x FOR PEER REVIEW 5 of 24 Sustainability 2019, 11, 5963 5 of 24 The observing site at mount Parnon is located next to the “George Pierce” alpine refuge of Parnon at an altitude2.3. Case of 1420 Studies m of and Mount located Parnon within Area a Natura 2000 protected area. It was discovered by amateur astronomers Theof Athens observing in site the at 1990s mount and Parnon has is been located an next unofficial to the “George place Pierce”for amateur alpine refugeastronomy of Parnon gatherings for the lastat antwo altitude decades. of 1420 In m2010, and locatedthe site within became a Natura the location 2000 protected of the area. 4th ItGreek was discoveredamateur byastronomy gatheringamateur organized astronomers by the of AthensSparta in Astronomical the 1990s and has Union been an“Dioskouroi” unofficial place and for amateur Astronomical astronomy Society of Patras “Orion”.gatherings This for gathering the last two led decades. the site In 2010,as well the as site the became annual the gathering location of theto fame 4th Greek all over amateur the country. astronomy gathering organized by the Sparta Astronomical Union “Dioskouroi” and Astronomical The Parnon observing site stands out for its dark skies, large and level observing ground, easy access Society of Patras “Orion”. This gathering led the site as well as the annual gathering to fame all by car andover vicinity the country. to Thethe Parnon “George observing Pierce” site standsalpine out refuge. for its dark Mount skies, Parnon large and is level an observing ideal place for designatingground, a dark easy accesssky park by car due and vicinityto it simultaneo to the “Georgeusly Pierce” being alpine a Natural refuge. Mount 2000 Parnonprotected is an idealarea, one of Greece’s placedarkest for designating places, and a dark a popular sky park dueastronomical to it simultaneously observing being site. a Natural The 2000borders protected of the area, officially designatedone protected of Greece’s darkestarea are places, shown and in a popularFigure astronomical 3, along with observing the area site. with The bordersastronomical of the offi activitiescially (pin designated protected area are shown in Figure3, along with the area with astronomical activities in Figure 3). The protected area is managed by the Management Body of Mount Parnon and Moustos (pin in Figure3). The protected area is managed by the Management Body of Mount Parnon and Wetland.Moustos The management Wetland. The managementbody manages body managesa wide aarea wide of area disconnected of disconnected and and varied sub-areas, sub-areas, with various statuseswith various of protection. statuses of protection. A detailed A detailed map of map the of protected the protected areas areas appears appears in FigureFigure4[49 4]. [49].

Figure 3.Figure The pin 3. The shows pin shows the location the location of ofth thee astronomy astronomy observingobserving site site in Parnon in Parnon while while the blue the border blue border coincides with the borders of the mount Parnon Natura 2000 protected area. coincides with the borders of the mount Parnon Natura 2000 protected area. The protected area comprises a large number of settlements (small or medium villages), but not any major cities. The protected area extends mainly in the former prefecture of Arcadia but also in parts of the former prefecture of Laconia. These now belong to the region of Peloponnese. The municipalities found in the protected area are the municipalities of North Kynouria, South Kynouria, Tripoli, Evrotas, and Sparti. Nearby large cities include Tripoli, Sparti, and Astros. Important settlements in the area near the astronomical observation site include Agios Petros, Karyes, Kastanitsa, Vamvakou, and Varvitsa. The settlements of Agios Petros and Karyes are particularly significant tourist villages due to the natural beauty of the area as well as the nearby monastery Malevi which attracts a significant number of tourists. Sustainability 2019, 11, 5963 6 of 24 Sustainability 2019, 11, x FOR PEER REVIEW 6 of 24

Figure 4. Detailed map of the protectedprotected areaarea [[49].49]. TheThe redred crosscross showsshows thethe locationlocation ofof thethe astronomy astronomy observing site in Parnon. 3. Results The protected area comprises a large number of settlements (small or medium villages), but not 3.1.any Lightingmajor cities. Inventory The protected and Influence area of extends Nearby Settlements mainly in the former prefecture of Arcadia but also in parts of the former prefecture of Laconia. These now belong to the region of Peloponnese. The The location of the examined villages forms a circle (Figure5) with the astronomical site in the municipalities found in the protected area are the municipalities of North Kynouria, South Kynouria, center. All these villages present significant activity as they are popular mountain tourist destinations Tripoli, Evrotas, and Sparti. Nearby large cities include Tripoli, Sparti, and Astros. Important and also centers of high-altitude agriculture. settlementsSustainability in2019 the, 11 area, x FOR near PEER the REVIEW astronomical observation site include Agios Petros, Karyes, Kastanitsa,7 of 24 Vamvakou, and Varvitsa. The settlements of Agios Petros and Karyes are particularly significant tourist villages due to the natural beauty of the area as well as the nearby monastery Malevi which attracts a significant number of tourists.

3. Results

3.1. Lighting Inventory and Influence of Nearby Settlements The location of the examined villages forms a circle (Figure 5) with the astronomical site in the center. All these villages present significant activity as they are popular mountain tourist destinations and also centers of high-altitude agriculture.

FigureFigure 5. 5.Location Location ofof thethe examined villages villages around around the the astronomical astronomical site. site.

LightingLighting inventory inventory inin thethe nearbynearby areaarea consistsconsists mainly of of old, old, unshielded, unshielded, or or semi-shielded semi-shielded luminairesluminaires either either in in their their original original formform usingusing older technology technology lamps lamps (high (high pressure pressure mercury mercury (HPM) (HPM) lamps)lamps) or or retro-fitted retro-fitted with with LED LED lamps lamps or compact or comp fluorescentact fluorescent lamps lamps (CFL). A(CFL). large A number large ofnumber luminaires of areluminaires damaged; are they damaged; are either they non-functional are either non-functi or with significantonal or with damage significant such as damage broken such protective as broken covers, missingprotective sanded covers, glasses, missing etc. sanded This significantly glasses, etc. This impacts significantly their operation impacts astheir luminaires operation and as luminaires distribution and distribution of light as well as their durability since the manufacturer’s Ingress Protection Marking (IP rating) is no longer valid. This leads to light sources and luminaire internals being exposed to exterior conditions and frequent lamp replacement, typically with low-cost and low- quality parts. A large variety of luminaire–lamp combinations were observed, leading to the conclusion that maintenance was carried out in an opportunistic way with no particular plan but rather a day-by-day approach. The most common public luminaire types in the area appear in Table 1.

Table 1. Designations and map symbols for most common outdoor luminaires in the area. Designatio Map Luminaire Light Source Frequency Luminaire Photo n Symbol Description Mostly CFL “Dish”-type but some L1 Prevalent luminaire LED (10–30 W)

HPM HPM (250– Low L2 streetlight 400 W). frequency

CFL retro- fitted streetlight CFL (18–30 Low L3 (former W) frequency HPM

streetlight)

CFL street CFL (18–30 Very L4 lanterns W) frequent

Sustainability 2019, Sustainability11, x FOR PEER 2019 REVIEW, 11, x FOR PEER REVIEW 7 of 24 7 of 24 Sustainability 2019, 11, x FOR PEER REVIEW 7 of 24 Sustainability 2019Sustainability,, 11,, xx FORFOR 2019 PEERPEER, 11 REVIEW,REVIEW x FOR PEER REVIEW 7 of 24 7 of 24

Figure 5. LocationFigure of the 5. examined Location ofvillages the examined around thevillages astronomical around the site. astronomical site. Figure 5. Location of the examined villages around the astronomical site. Figure 5. LocationFigure of 5. the Location examined of the villages examined around villages the astronomical around the astronomical site. site. Lighting inventoryLighting in theinventory nearby inarea the consists nearby mainlyarea consists of old, mainly unshielded, of old, or unshielded, semi-shielded or semi-shielded Lighting inventoryLighting ininventory the nearby in thearea nearby consists area mainly consists of old,mainly unshielded, of old, unshielded, or semi-shielded or semi-shielded luminairesLighting eitherluminaires inventory in their original either in the in form theirnearby using original area older consistsform technology using mainly older lamps of technology old, (high unshielded, pressure lamps (highmercury or semi-shielded pressure (HPM) mercury (HPM) luminairesluminaires eitherluminaireseitherluminaires inin theirtheir eithereither originaloriginal inin theirtheir formform originaloriginal usingusing formformolderolder using usingtechnologytechnology olderolder technologytechnologylampslamps (high(high lampslamps pressurepressure (high(high mercurymercury pressurepressure (HPM)(HPM) mercurymercury (HPM)(HPM) lamps)luminaires or retro-fitted eitherlamps) in ortheirwith retro-fitted originalLED lamps form with orusing LED comp older lampsact technologyfluorescent or comp act lampslamps fluorescent (high (CFL). pressure Alamps large mercury(CFL). number A (HPM) largeof number of lamps)lamps) oror retro-fittedretro-fittedlamps)lamps) oror retro-fittedretro-fittedwithwith LEDLED lampswithlampswith LEDLED oror compcomp lampslampsact oror fluorescent compcompact fluorescentlamps (CFL). lamps A large (CFL). number A large of number of luminaireslamps) or are retro-fitted luminairesdamaged; withtheyare damaged; areLED either lamps they non-functi or are comp eitheronalact non-functifluorescentor with significantonal lamps or with (CFL).damage significant A suchlarge as damagenumber broken such of as broken Sustainabilityluminairesluminaires2019 luminairesareluminairesare, 11 ,damaged;damaged; 5963 areare they theydamaged;damaged; areare eithereither theythey non-functinon-functi areare eithereitheronal non-functinon-functi or withonal significant or with damagesignificant such damage as broken such as broken7 of 24 protectiveluminaires covers, areprotective damaged;missing covers, sanded they missing areglasses, either sanded etc. non-functi This glasses, significantlyonal etc. or This with impacts significantly significant their operation impactsdamage their assuch luminaires operation as broken as luminaires protective covers,protective missing covers, sanded missing glasses, sanded etc. glasses, This significantly etc. This significantly impacts their impacts operation their as operation luminaires as luminaires andprotective distribution covers,and of distribution missinglight as sandedwell of aslight glasses, their as durabi welletc. This aslity theirsignificantly since durabi the manufacturlity impacts since their theer’s operationmanufactur Ingress asProtection er’sluminaires Ingress Protection and distributionand distribution of light as ofwell light as astheir well durabi as theirlitylity sincesincedurabi thethelitylity manufactur manufactursincesince thethe manufacturmanufacturer’s Ingresser’s Protection Ingress Protection Markingand distribution (IP rating)Marking ofis lightno(IP longer rating)as well valid. is asno their Thislonger leadsdurabi valid. tolity lightThis since sourcesleads the tomanufactur andlight luminaire sourceser’s Ingressandinternals luminaire Protection being internals being of lightMarking as well (IPMarking asrating) their (IPis durability no rating) longer is since valid.no longer the This manufacturer’s valid.leads Thisto light leads sources Ingress to light and Protection sources luminaire and Marking internalsluminaire (IPbeing internals rating) being is no exposedMarking to exterior(IPexposed rating) conditions isto noexterior longer and conditions frequentvalid. This lampand leads frequentreplacement, to light lamp sources typicallyreplacement, and withluminaire typicallylow-cost internals withand low-low-cost being and low- longerexposed valid. to This exposedexterior leads toconditions toexterior light conditions sourcesand frequent and and lamp luminaire frequent replacement, lamp internals replacement, typically being with exposedtypically low-cost towith exteriorand low-cost low- conditions and low- qualityexposed parts. to exteriorqualityA large parts. conditionsvariety A oflarge andluminaire–lamp varietyfrequent of lamp luminaire–lamp combinations replacement, werecombinationstypically observed, with were low-costleading observed, andto the low- leading to the quality parts.quality A large parts. variety A large of varietyluminaire–lamp of luminaire–lamp combinations combinations were observed, were leadingobserved, to leadingthe to the andconclusionquality frequent parts.that lampconclusion maintenance A replacement,large thatvariety was maintenance carriedof typically luminaire–lamp out was in with carriedan opportunistic low-costcombinations out in an and wayopportunistic were low-quality with observed,no particularway parts. withleading planno A particular largetobut the variety plan but of conclusion conclusionconclusionthat maintenance thatthat maintenancemaintenance was carried waswas out carriedcarriedin an opportunistic outout inin anan opportunisticopportunistic way with no wayway particular withwith nono plan particularparticular but planplan butbut luminaire–lampratherconclusion a day-by-day thatrather combinations maintenance approach. a day-by-day The was were approach.most carried observed, common out The in mostpub leadinganlic opportunisticcommon luminaire to the pub types conclusion licway luminaire in with the areano that types particular appear maintenance in the in planareaTable appearbut was carriedin Table rather a day-by-dayratherrather aa day-by-day day-by-dayapproach. The approach.approach. most common TheThe mostmost pub commoncommonliclic luminaireluminaire pubpubliclic typestypes luminaireluminaire inin thethe typestypes areaarea appearappearinin thethe areaarea inin TableTable appearappear inin TableTable out1. inrather an opportunistica day-by-day1. approach. way with The most no particular common pub planlic luminaire but rather types a day-by-dayin the area appear approach. in Table The most 1. 1. common public luminaire types in the area appear in Table1. Table 1. DesignationsTable and1. Designations map symbols and for map most symbols common for outdoor most common luminaires outdoor in the luminaires area. in the area. Table 1. Designations and map symbols for most common outdoor luminaires in the area. Table 1. DesignationsTable 1. Designations and map symbols and map for mostsymbols common for most outdoor common luminaires outdoor in luminaires the area. in the area. DesignatioTable 1.DesignatioDesignationsMap Luminaire andMap map symbolsLuminaire for most common outdoor luminaires in the area. DesignatioDesignatioMap MapLuminaire Luminaire Light Source Light Frequency Source Frequency Luminaire Photo Luminaire Photo n Symboln DescriptionSymbol DescriptionLight Source Light Frequency Source Frequency Luminaire Luminaire Photo Photo Designationn MapSymboln Symbol SymbolDescription Luminaire Description Description Light Source Frequency Luminaire Photo Mostly CFL Mostly CFL Mostly CFLMostly CFL “Dish”-type “Dish”-type“Dish”-typebut some Mostlybutbut CFLsomesome but L1 L1L1 “Dish”-type“Dish”-type but some butPrevalent some PrevalentPrevalent L1L1 L1 luminaire“Dish”-type luminaireluminaire luminaireLED (10–30 some LEDLED LED Prevalent (10–30(10–30 (10–30 PrevalentPrevalent luminaireluminaire luminaireLED (10–30 LED W) (10–30 W) W) W) W)

HPM HPMHPM (250– HPMLow (250– Low L2 L2 HPM HPMHPM (250–HPM (250–Low Low L2L2 L2 streetlightHPM streetlightstreetlight400 W). HPM (250–400frequency400 W). W). Lowfrequency frequency streetlight streetlightstreetlight400 W). 400frequencyfrequency W). frequencyfrequency

CFL retro- CFL retro- CFL retro-CFL retro- CFLfitted retro- fitted fittedfitted fittedfitted streetlightCFL retro-fittedstreetlightCFL (18–30 CFL Low(18–30 Low L3 L3 streetlight streetlightstreetlightCFL (18–30 CFL (18–30Low Low L3L3 L3 (formerstreetlight (former(former HPMW) CFLfrequency (18–30W) W) Lowfrequency frequency (former(former streetlight) (former(former W) W)frequencyfrequency frequencyfrequency HPM(former HPM W) frequency HPM HPM streetlight) streetlight) streetlight)streetlight)streetlight)

CFL street CFLCFL street (18–30 CFL Very(18–30 Very L4L4 L4 CFLCFL street street CFL lanterns streetCFL (18–30 CFLCFL (18–30 (18–30Very W) VeryVery frequent L4 L4 lanterns lanternsW) frequentW) frequent lanternslanterns lanternslanternsW) W)frequentfrequent frequentfrequent Sustainability 2019Sustainability,, 11,, xx FORFOR 2019 PEERPEER,, 11 REVIEWREVIEW,, xx FORFOR PEER PEER REVIEWREVIEW 8 of 24 8 of 24 Sustainability 2019Sustainability, 11, x FOR 2019 PEER, 11 REVIEW, x FOR PEER REVIEW 8 of 24 8 of 24

High High Sodium SodiumHigh HighHigh pressureLow Low L5L5 L5 SodiumSodium streetlightsSodiumpressure pressureLow LowLow frequency L5 L5 streetlights streetlightspressure pressuresodiumfrequencyfrequency frequency streetlights streetlightssodium sodiumfrequency frequency sodium sodium

Halogen Halogen L6L6 L6 HalogenHalogen floodlightsHalogenHalogen Halogen Frequent Frequent Frequent L6 L6 floodlightsfloodlights floodlightsfloodlightsHalogen HalogenFrequent Frequent floodlights floodlights

Metal halideMetal halide Low Low L7L7 L7 MetalMetal halide halideMetal floodlightsMetal halide halide Metal Metal halide halideLow LowLow frequency L7 L7 floodlightsfloodlights floodlightsfloodlightsMetal halide Metal frequencyfrequency halide frequencyfrequency floodlights floodlights frequency frequency

LED LED Low Low L8 L8 LED LED LED LEDLow Low L8L8 L8 floodlightsLED floodlights floodlightsLED LEDLEDfrequency Lowfrequency frequency floodlights floodlights frequency frequency

Abbreviations:Abbreviations: CFL, compact CFL, fluorescent compact lamps; fluorescent LED, light-emitting lamps; LED, light-emitting diode; HPM, highdiode; pressure HPM, high mercury. pressure mercury. Abbreviations:Abbreviations:Abbreviations: CFL, compact CFL, compact CFL, fluorescent compact fluorescent lamps; fluorescent lamps;LED, light-emitting lamps; LED, light-emittingLED, light-emitting diode; HPM, diode; highdiode; HPM, pressure HPM, high high pressuremercury. pressure mercury. mercury. Agios PetrosAgios is the Petrosclosest is village the closest to the village astronom to theicalical astronom sitesite andand icalmostlymostly site servesservesand mostly asas aa locallocal serves shoppingshopping as a local shopping Agios PetrosAgios is the Petros closest is village the closest to the village astronom to theical astronom site and icalmostly site servesand mostly as a local serves shopping as a local shopping and entertainmentand entertainment center. Lighting center. in LightingAgios Petr inos Agios is predominantly Petros is predominantly of two types—the of two dish-typetypes—the dish-type and entertainmentand entertainment center. Lighting center. in LightingAgios Petr inos Agios is predominantly Petros is predominantly of two types—the of two dish-typetypes—the dish-type luminaireluminaire (L1)(L1)luminaire andand mercurymercury (L1) and streetlightsstreetlights mercury (L2)—while(L2)—whilestreetlights (L2)—whileaa numbernumber ofof a streetlightsstreetlightsnumber of havehavestreetlights beenbeen retrofittedretrofitted have been retrofitted luminaire (L1)luminaire and mercury (L1) and streetlights mercury (L2)—whilestreetlights (L2)—whilea number of a streetlightsnumber of havestreetlights been retrofitted have been retrofitted with CFL lamps.with DetailsCFL lamps. on the Details lighting on inventorythe lighting of inventory Agios Petros of Agios are given Petros in areFigure given 6 and in Figure Table 62. and Table 2. with CFL lamps.with DetailsCFL lamps. on the Details lighting on theinventory lighting of inventory Agios Petros of Agios are given Petros in areFigure given 6 and in Figure Table 62. and Table 2. InIn Karyes,Karyes, mostlymostlyIn Karyes, “dish”-type“dish”-type mostly “dish”-typeluminairesluminaires andand luminaires lantlanterns and are lantinstallederns are (Figure installed 7). Figures (Figure 8–10 7). Figures present 8–10 present In Karyes, mostlyIn Karyes, “dish”-type mostly “dish”-typeluminaires and luminaires lanterns and are lantinstallederns are (Figure installed 7). Figures (Figure 8–10 7). Figures present 8–10 present thethe lightinglighting inventoryinventorythe lighting forfor inventory thethe restrest ofof for thethe the examinedexamined rest of the vivi llages.examinedllages. ItIt mustmust villages. bebe notednoted It must thatthat be forfor noted thethe totaltotal that examinedexaminedfor the total examined the lighting inventorythe lighting for inventory the rest of for the the examined rest of the vi llages.examined It must villages. be noted It must that be for noted the total that examinedfor the total examined area the privatearea outdoor the private lighting outdoor was lighting minimal. was minimal. area the privatearea outdoor the private lighting outdoor was lighting minimal. was minimal.

Figure 6. LightingFigure inventory 6. Lighting map inventory in Agios mapPetros. in Agios Petros. Figure 6. LightingFigure inventory 6. Lighting map inventory in Agios mapPetros. in Agios Petros. Sustainability 2019, 11, x FOR PEER REVIEW 8 of 24

High Sodium Low L5 pressure streetlights frequency sodium

Halogen L6 Halogen Frequent floodlights

Metal halide Low L7 Metal halide floodlights frequency

LED Low L8 LED floodlights frequency

Sustainability 2019, 11, 5963 8 of 24 Abbreviations: CFL, compact fluorescent lamps; LED, light-emitting diode; HPM, high pressure mercury.

Agios Petros isis thethe closestclosest villagevillage toto thethe astronomicalastronomical sitesite andand mostlymostly servesservesas asa a local local shopping shopping and entertainmententertainment center.center. Lighting in AgiosAgios PetrosPetros isis predominantlypredominantly ofof twotwo types—thetypes—the dish-typedish-type luminaireluminaire (L1)(L1) andand mercurymercury streetlightsstreetlights (L2)—while(L2)—while aa numbernumber ofof streetlightsstreetlights havehave beenbeen retrofitted retrofitted withwith CFLCFL lamps.lamps. Details on the lighting inventory of Agios Petros are given in Figure6 6 and and TableTable2 .2. In Karyes,Karyes, mostlymostly “dish”-type “dish”-type luminaires luminaires and and lanterns lanterns are are installed installed (Figure (Figure7). Figures 7). Figures8–10 present8–10 present the lightingthe lighting inventory inventory for for the the rest rest of theof the examined examined villages. villages. It mustIt must be be noted noted that that for for the the total total examined examined area the private outdooroutdoor lightinglighting waswas minimal.minimal.

Sustainability 2019, 11, x FOR PEER REVIEW 9 of 24 FigureFigure 6.6. LightingLighting inventoryinventory mapmap inin AgiosAgios Petros.Petros.

FigureFigure 7. 7.Lighting Lighting inventoryinventory mapmap inin Karyes.Karyes.

Figure 8. Lighting inventory map in Kastanitsa. Sustainability 2019, 11, x FOR PEER REVIEW 9 of 24

Sustainability 2019, 11, 5963 9 of 24 Figure 7. Lighting inventory map in Karyes.

Sustainability 2019, 11, x FOR PEER FigureREVIEWFigure 8.8. Lighting Lighting inventoryinventory mapmap inin Kastanitsa.Kastanitsa. 10 of 24

FigureFigure 9.9. LightingLighting inventoryinventory mapmap inin Vamvakou.Vamvakou.

Table 2. Outdoor lighting installed power inventory of the examined villages.

Outdoor Lighting Outdoor Lighting Outdoor Village Population Installed Power Installed Power per Luminaires per (kW) Resident (W/person) Resident Agios 717 15 21 0.23 Petros Karyes 926 7.5 8 0.20 Kastanitsa 175 5.7 32.8 0.92 Vamvakou 88 4.9 55.5 0.88 Varvitsa 118 3.8 32.5 0.91 Total 2024 39.8 19.65 0.34

Figure 10. Lighting inventory map in Varvitsa.

Table 2. Outdoor lighting installed power inventory of the examined villages.

Outdoor Lighting Outdoor Lighting Outdoor Village Population Installed Power Installed Power per Luminaires per (kW) Resident (W/person) Resident Agios Petros 717 15 21 0.23 Karyes 926 7.5 8 0.20 Kastanitsa 175 5.7 32.8 0.92 Vamvakou 88 4.9 55.5 0.88 Varvitsa 118 3.8 32.5 0.91 Total 2024 39.8 19.65 0.34

3.2. Lighting Measurements and Calculations Sample measurements of most common lamps were made in order to achieve the following: • Verify light source type and color temperature when these were not readily apparent Sustainability 2019, 11, x FOR PEER REVIEW 10 of 24

Sustainability 2019, 11, 5963 10 of 24 Figure 9. Lighting inventory map in Vamvakou.

FigureFigure 10.10. LightingLighting inventoryinventory mapmap inin Varvitsa.Varvitsa.

3.2. Lighting MeasurementsTable 2. Outdoor and Calculations lighting installed power inventory of the examined villages.

Sample measurements ofOutdoor most common Lighting lamps wereOutdoor made in Lighting order to achieve the following:Outdoor Village Population Installed Power Installed Power per Luminaires per Verify light source type and color temperature when these were not readily apparent • (kW) Resident (W/person) Resident Verify what the true spectrum of light sources were vs. the manufacturer’s correlated •Agios Petros 717 15 21 0.23 color temperature Karyes 926 7.5 8 0.20 Assess the impact of light sources on light pollution which is more pronounced when emitting • Kastanitsa 175 5.7 32.8 0.92 large amounts of blue light Vamvakou 88 4.9 55.5 0.88 3.2.1.Varvitsa Luminance and118 Illuminance Measurements 3.8 for the Most Prevalent 32.5 Luminaire Type 0.91 Total 2024 39.8 19.65 0.34 A number of measurements regarding luminance (cd/m2) and illuminance (lx) were performed in3.2. order Lighting to assessMeasurements the performance and Calculations of luminaires. It was particularly interesting to measure the performance of the prevalent dish-type luminaires in their typical CFL version. Measurements for the “dish”-typeSample luminaires measurements are provided of most common in Table3 .lamps were made in order to achieve the following: • Verify light source type and color temperature when these were not readily apparent Table 3. On-site luminance (cd/m2) and illuminance (lx) measurements for the dish-type luminaire.

Parameter Measured Value Maximum luminance (under the CFL luminaire) 0.3 cd/m2 Minimum luminance (between two consecutive CFL luminaires) 0.03 cd/m2 Maximum illuminance at street level of CFL luminaire 2.4 lx Minimum illuminance at street level of CFL luminaire 0.2 lx Maximum illuminance at street level of LED luminaire 9.7 lx Minimum illuminance at street level of LED luminaire 0.4 lx

3.2.2. Spectral and Color Temperature The spectral characteristics and color performance of the most prevalent lamp types (LED, CFL, and HPM lamps) are shown in Figure 11. Sustainability 2019, 11, x FOR PEER REVIEW 11 of 24

• Verify what the true spectrum of light sources were vs. the manufacturer’s correlated color temperature • Assess the impact of light sources on light pollution which is more pronounced when emitting large amounts of blue light

3.2.1. Luminance and Illuminance Measurements for the Most Prevalent Luminaire Type

A number of measurements regarding luminance (cd/m2) and illuminance (lx) were performed in order to assess the performance of luminaires. It was particularly interesting to measure the performance of the prevalent dish-type luminaires in their typical CFL version. Measurements for the “dish”-type luminaires are provided in Table 3.

Table 3. On-site luminance (cd/m2) and illuminance (lx) measurements for the dish-type luminaire. Parameter Measured Value Maximum luminance (under the CFL luminaire) 0.3 cd/m2 Minimum luminance (between two consecutive CFL luminaires) 0.03 cd/m2 Maximum illuminance at street level of CFL luminaire 2.4 lx Minimum illuminance at street level of CFL luminaire 0.2 lx Maximum illuminance at street level of LED luminaire 9.7 lx Minimum illuminance at street level of LED luminaire 0.4 lx

3.2.2. Spectral and Color Temperature

SustainabilityThe spectral2019, 11characteristics, 5963 and color performance of the most prevalent lamp types (LED,11 of CFL, 24 and HPM lamps) are shown in Figure 11.

(a) (b)

(c) (d)

FigureFigure 11. 11. (a)( a2700) 2700 K KLED LED lamp lamp spectrum; spectrum; ( (bb)) 5500 5500 K CFLCFL lamplamp spectrum;spectrum; ( c()c 4000) 4000 K K LED LED lamp lamp spectrum;spectrum; (d) ( d5000) 5000 K KHPM HPM lamp lamp spectrum. spectrum.

Many of the installed lamps had a rich blue color in their spectrum resulting in high values of correlated color temperature (CCT) while the color rendering index (CRI; Ra8) values were above 80 for the eight corresponding colors (Figure 11b–d). However, the light intensity of the sources was low, resulting in lower lighting levels (Table3) than the corresponding ones indicated from EN 13201-2 [ 50]. As shown in Figure 11a, existing lamps were replaced by newer LED lamps with a lower content of blue color (380–500 nm). Education of public authorities was essential for selecting warmer CCT (Figure 11a) rather than neutral CCT (Figure 11b). In the future, there will be a wider selection of LED lamps according to the appropriate CCT and CRI values [18,51,52].

3.2.3. G-Index Calculated Values Table4 along with Figures 12 and 13 show the calculated values of G-index [ 24,53] in compare with the limit values concerning ecologically sensitive areas and the areas near the optical astronomy observatory areas as these have been adapted from EU technical guides [24]. Sustainability 2019, 11, x FOR PEER REVIEW 12 of 24

Many of the installed lamps had a rich blue color in their spectrum resulting in high values of correlated color temperature (CCT) while the color rendering index (CRI; Ra8) values were above 80 for the eight corresponding colors (Figure 11b–d). However, the light intensity of the sources was low, resulting in lower lighting levels (Table 3) than the corresponding ones indicated from EN 13201-2 [50]. As shown in Figure 11a, existing lamps were replaced by newer LED lamps with a lower content of blue color (380–500 nm). Education of public authorities was essential for selecting warmer CCT (Figure 11a) rather than neutral CCT (Figure 11b). In the future, there will be a wider selection of LED lamps according to the appropriate CCT and CRI values [18,51,52].

3.2.3. G-Index Calculated Values Table 4 along with Figures 12 and 13 show the calculated values of G-index [24,53] in compare with the limit values concerning ecologically sensitive areas and the areas near the optical astronomy observatory areas as these have been adapted from EU technical guides [24]. Sustainability 2019, 11, 5963 12 of 24 Table 4. Measured and calculated values depending the lamp types installed in the examined area.

TableSpectrum 4. Measured and Area calculated values Index dependingG * Q (%) the lamp* CCT types (K) installed CRI in the Lamp examined Type area. S1 Agios Petros 1.91 17 2678 82 LED Spectrum Area Index G * Q (%) * CCT (K) CRI Lamp Type S2 Agios Petros 0.74 51 5237 73 CFL S3S1 Agios Agios Petros Petros 1.910.92 17 43 2678 4181 84 82 LED LED S4S2 Agios Agios Petros Petros 0.740.75 51 55 52375300 80 73 CFL CFL S3 Agios Petros 0.92 43 4181 84 LED S5 Agios Petros 2.00 16 2667 82 LED S4 Agios Petros 0.75 55 5300 80 CFL S6S5 Agios Agios Petros Petros 2.000.74 16 50 26675010 78 82 CFL LED S7S6 Vamvakou Agios Petros 0.740.51 50 63 50106063 77 78 CFL CFL S8S7 Vamvakou Vamvakou 0.510.54 63 61 60633689 40 77 HPM CFL S9S8 Vamvakou Vamvakou 0.540.44 61 66 36894098 33 40 HPM HPM S10S9 VamvakouKaryes − 0.440.03 103 66 40985167 55 33 HPM HPM S10 Karyes 0.03 103 5167 55 HPM S11 Karyes −−0.26 127 6546 57 HPM S11 Karyes 0.26 127 6546 57 HPM S12 Varvitsa −0.88 44 4242 82 LED S12 Varvitsa 0.88 44 4242 82 LED S13S13 Varvitsa Varvitsa 0.140.14 8888 42564256 39 HPM HPM S14S14 Varvitsa Varvitsa 1.051.05 3838 40724072 80 LED LED S15S15 Varvitsa Varvitsa 1.061.06 3838 40654065 80 LED LED S16S16 Varvitsa Varvitsa 1.071.07 3737 40584058 80 LED LED S17S17 Kastanitsa Kastanitsa 1.061.06 38 38 40634063 80 LED LED S18 Kastanitsa 1.09 37 4056 80 LED S18 Kastanitsa 1.09 37 4056 80 LED S19 Kastanitsa 1.10 36 4043 81 LED S19 Kastanitsa 1.10 36 4043 81 LED * Calculated values according Galadi-Enriquez research [24,53]. Abbreviations: CCT, correlated color temperature; CRI:* Calculated color rendering values index. according Galadi-Enriquez research [24,53]. Abbreviations: CCT, correlated color temperature; CRI: color rendering index.

Figure 12. Values of G-index derived from the measured spectrum of the lamp types across the Figure 12. Values of G-index derived from the measured spectrum of the lamp types across the examined area. Sustainabilityexamined 2019 area., 11, x FOR PEER REVIEW 13 of 24

FigureFigure 13. 13.Measured Measured CCTCCT ofof the lamp type typess across across the the examined examined area. area.

3.2.4. Identifying Lighting Malpractices in Villages The Caryatid monument in the village of Karyes (Figure 14a) is a prominent example of energy waste and over-illumination. The monument was built in 1983 and is a copy of part of the Erechtheion temple in the Acropolis. Some historians suggest that the female figures of the Erechtheion represented the punishment of the women of Karyes, who were condemned to slavery after betraying Athens by siding with Persia in the Greco-Persian Wars. The caryatid monument is located on a small hill at the edge of the village. At night it is illuminated with three high-intensity metal-halide floodlights (Figure 14b). The monument is marble-white, and the excessive illumination is apparent just by visual inspection. It must be noted that the hill where the monument is located is not illuminated so luminance of surroundings is very low. Measurements were taken in order to investigate the actual illumination levels; they are listed in Table 5. Measurements confirm the visual impression since 200 lx is a high value of illuminance for a monument located in a dark area. Another interesting observation comes by comparing the installed power for lighting in the village of Karyes which is 2.6 kW with the value of 2 kW of the monument. Data reveal that the power spent on lighting a single monument is of the same order of magnitude as the power spent for lighting the main streetlights in Karyes (“dish”-type luminaires).

(a) (b)

Figure 14. (a) The Caryatid monument in Karyes. (b) High-intensity floodlights excessively illuminate the Caryatid monument.

Table 5. Caryatid monument measurements. Caryatid Monument Measurements Sustainability 2019, 11, x FOR PEER REVIEW 13 of 24

Sustainability 2019, 11, 5963 13 of 24 Figure 13. Measured CCT of the lamp types across the examined area.

3.2.4.3.2.4. Identifying Identifying Lighting Lighting Malpractices Malpractices in in Villages Villages TheThe Caryatid monument in the village of Karyes (Figure 1414a)a) is a prominentprominent exampleexample ofof energyenergy waste and over-illumination. The monument waswas builtbuilt inin 19831983 andand isis aa copy ofof part ofof the Erechtheion templetemple inin the the Acropolis. Acropolis. Some Some historians historians suggest suggest that the that female the figuresfemale of figures the Erechtheion of the Erechtheion represented representedthe punishment the punishment of the women of ofthe Karyes, women who of Karyes were condemned, who were condemned to slavery after to slavery betraying after Athens betraying by Athenssiding withby siding Persia with in thePersia Greco-Persian in the Greco-Persian Wars. The Wars. caryatid The caryatid monument monument is located is located on a small on a hill small at hillthe edgeat the of edge the village. of the Atvillage. night At it is night illuminated it is illuminated with three high-intensitywith three high-intensity metal-halide metal-halide floodlights floodlights(Figure 14b). (Figure The monument14b). The monument is marble-white, is marble-white, and the excessiveand the excessive illumination illumination is apparent is apparent just by justvisual by inspection. visual inspection. It must beIt notedmust thatbe noted the hill that where thethe hill monument where the is monument located is not is illuminatedlocated is not so illuminatedluminance of so surroundings luminance of is verysurroundings low. Measurements is very low. were Measurements taken in order were to investigate taken in the order actual to investigateillumination the levels; actual they illumination are listed in levels; Table 5they. Measurements are listed in Table confirm 5. theMeasurements visual impression confirm since the 200visual lx impressionis a high value since of 200 illuminance lx is a high for value a monument of illuminan locatedce for in a darkmonument area. Another located interestingin a dark area. observation Another interestingcomes by comparing observation the comes installed by comparing power for the lighting instal inled the power village for oflighting Karyes in which the village is 2.6 of kW Karyes with whichthe value is 2.6 of kW 2 kW with of thethe monument.value of 2 kW Data of the reveal monument. that the powerData reveal spent that on lightingthe power a single spent monumenton lighting ais single of the monument same order is of of magnitude the same asorder the powerof magnitude spent for as lightingthe power the spent main streetlightsfor lighting inthe Karyes main streetlights(“dish”-type in luminaires). Karyes (“dish”-type luminaires).

(a) (b)

FigureFigure 14. 14. ((aa)) The The Caryatid Caryatid monument monument in in Karyes. Karyes. ( (bb)) High-intensity High-intensity floodlights floodlights excessivelyexcessively illuminateilluminate thethe Caryatid Caryatid monument. monument.

Table 5.5. Caryatid monument measurements. CaryatidCaryatid Monument Monument MeasurementsMeasurements Illuminance at the surface of the monument (lx) 200 Luminance towards the monument (cd/m2) 50 Correlated color temperature (K) 6000 Color index (Ra) 58

4. Light Pollution Sources and Measurements Light pollution does not only originate locally but also propagates from far away, even hundreds of kilometers afar. By recording the direction from which distant light pollution originates it is possible to assess its sources and take appropriate measures. Especially in very dark sites, light pollution is more likely to originate from adjacent highways or large cities than nearby small villages, although this is not a rule and should in any case be demonstrated by measurements. Sustainability 2019, 11, 5963 14 of 24

4.1. Skyglow Measurements Using Wide Field Photography The easiest way to record the direction of skyglow origin is to use wide-field photography of the horizon. This records the so-called light domes that originate from distant skyglow sources. A wide-field photograph of the same exposure should be taken for all four cardinal points, one centered in each. These photos can then be used to calculate the azimuth of the skyglow origin and using a map it can be related to a major city or road. All the measurements were taken from the astronomical site at mount Parnon near the alpine refuge. In order to trace the source of light pollution that affects the astronomical site, wide-field photographs were taken centered on the four cardinal points. The equipment used was:

Canon T4i DSLR camera • Samyang 8 mm fisheye lens • Manfrotto Compact Advanced aluminum tripod with 3-way head • This combination provided a field of view of approximately 140 degrees that allowed for easy comparison of illumination in different directions. Of course, all four photographs were taken using the same settings, as they appear in Table6.

Table 6. Camera settings for measurement of light pollution (applied to all following photos).

Setting Value Aperture f/3.5 Exposure 30 s ISO 800 sensitivity

The pictures presented (Figures 15 and 16) were not modified in any other way except linear brightness enhancement for better presentation of the result. This linear enhancement does not affect the relative brightness of different pixels (as non-linear processing would). The camera was leveled horizontally using the tripod spirit level and was towards the cardinal points using a compass. Due to the existence of vegetation as well as uneven ground, photos need to be compared at the same celestial altitude in order for comparison of light pollution. This was achieved with the help of visible stars whose altitude could be calculated for the known place, date, and time. In order to compare small differences in brightness, measurements were not performed visually but rather a tool was used to calculate pixel values. Pixel values are counted in analog to digital units (ADUs) and their value ranges from 0 (total black) to 214 which is the maximum pixel value (due to the sensor being 14-bit) and the point where the sensor pixel is completely saturated (total white). Measurements of pixel values were not performed at single pixels in order to avoid faint stars, hot pixels, and other artifacts. Instead, the average of a 21 21 pixel matrix was measured using the × software Nebulosity. A sample screenshot of the process is shown in Figure 15. Sustainability 2019, 11, x FOR PEER REVIEW 15 of 24

Sustainability 2019, 11, 5963 15 of 24 Sustainability 2019, 11, x FOR PEER REVIEW 15 of 24

Figure 15. Calculating pixel values which correspond to brightness using the Nebulosity software [54].

The condition of the night sky illumination at the astronomical site looking towards the cardinal orientations is shown in Figure 16. The measurements are in pixel values (ADUs). The light pollution towards the north (N) is increased. East (E) is significantly darker with a pixel value of 9000 ADUs while the south (S) has a pixel value of 8000 ADUs. The south gets brighter towards the west (W). Measurements show that NE presents the highest values (11,000 ADUs), N the second highest (10,000 ADUs), while NW is significantly (9500 ADUs) darker. Complete measurements appear in Figure 17. By overlaying the cardinal points over a wide map of the area (Figure 18a), it is obvious that peaks in light pollution are due to the influence of the local nearby cities of Tripoli and Sparti. Furthermore, by overlaying the cardinal points over a narrow map of the area (Figure 18b), there is not a particular conclusion as to the influence of local villages in the visible light pollution because orientation of villages largely coincides with those of large cities which are expected to significantly contribute to local skyglow. FigureFigure 15. 15. CalculatingCalculating pixel pixel values values which which correspond correspond to br brightnessightness using the Nebulosity softwaresoftware [[54].54].

The condition of the night sky illumination at the astronomical site looking towards the cardinal orientations is shown in Figure 16. The measurements are in pixel values (ADUs). The light pollution towards the north (N) is increased. East (E) is significantly darker with a pixel value of 9000 ADUs while the south (S) has a pixel value of 8000 ADUs. The south gets brighter towards the west (W). Measurements show that NE presents the highest values (11,000 ADUs), N the second highest (10,000 ADUs), while NW is significantly (9500 ADUs) darker. Complete measurements appear in Figure 17. By overlaying the cardinal points over a wide map of the area (Figure 18a), it is obvious that peaks in light pollution are due to the influence of the local nearby cities of Tripoli and Sparti. Furthermore, by overlaying the cardinal points(a) over a narrow map of the area (Figure 18b),(b there) is not a particular conclusion as to the influence of local villages in the visible light pollution because orientation of villages largely coincides with those of large cities which are expected to significantly contribute to local skyglow.

(c) (d)

Figure 16. Light pollution towards the cardinal orientations: (a) north, (b) east, (c), south, and (d) West.

The condition of the night sky illumination at the astronomical site looking towards the cardinal (a) (b) orientations is shown in Figure 16. The measurements are in pixel values (ADUs). The light pollution towards the north (N) is increased. East (E) is significantly darker with a pixel value of 9000 ADUs while the south (S) has a pixel value of 8000 ADUs. The south gets brighter towards the west (W). Measurements show that NE presents the highest values (11,000 ADUs), N the second highest (10,000 ADUs), while NW is significantly (9500 ADUs) darker. Complete measurements appear in Figure 17. By overlaying the cardinal points over a wide map of the area (Figure 18a), it is obvious that peaks in light pollution are due to the influence of the local nearby cities of Tripoli and Sparti. Furthermore, by overlaying the cardinal points over a narrow map of the area (Figure 18b), there is

(c) (d) Sustainability 2019, 11, 5963 16 of 24

Sustainability 2019, 11, x FOR PEER REVIEW 16 of 24 Sustainabilitynot a particular 2019, 11 conclusion, x FOR PEER asREVIEW to the influence of local villages in the visible light pollution because 16 of 24 Figure 16. Light pollution towards the cardinal orientations: (a) north, (b) east, (c), south, and (d) West. orientation of villages largely coincides with those of large cities which are expected to significantly Figure 16. Light pollution towards the cardinal orientations: (a) north, (b) east, (c), south, and (d) West. contribute to local skyglow.

Figure 17. Summary of photographic brightness measurements per direction in pixel values (analog Figure 17. Summary of photographic brightness measurements per direction in pixel values (analog to toFigure digital 17. units, Summary ADUs) of for photographic each cardinal brightness point as indicatedmeasurements by the per embe directiondded image in pixel in thevalues center. (analog digital units, ADUs) for each cardinal point as indicated by the embedded image in the center. to digital units, ADUs) for each cardinal point as indicated by the embedded image in the center.

(a) (b) (a) (b) FigureFigure 18. 18. CardinalCardinal points points centered centered on on the the ( (aa)) astronomical astronomical site site (wide map) and ( b) village map. Figure 18. Cardinal points centered on the (a) astronomical site (wide map) and (b) village map. 4.2.4.2. Sky Sky Brightness Brightness Measurements Measurements Using Using SQM SQM Equipment Equipment 4.2. SkyTheThe Brightness sky sky at thethe Measurements centercenter ofof the the area Usingarea of of interestSQM interest Equipment was was assessed assessed using using a Unihedron a Unihedron SQM-L SQM-L instrument instrument [55]. The SQM device is small, portable, and economical. It consists of a photometer, visual filter, display, [55]. TheThe skySQM at devicethe center is small, of the portable,area of interest and economical. was assessed It consistsusing a Unihedronof a photometer, SQM-L visual instrument filter, and electronics to perform the measurement. Each measurement takes a few seconds and displays the display,[55]. The and SQM electronics device is tosmall, perform portable, the measurem and economical.ent. Each It measurementconsists of a photometer,takes a few secondsvisual filter, and sky brightness in visual magnitudes per square arc second. This method has been used globally for dark displaysdisplay, andthe skyelectronics brightness to performin visual themagnitudes measurem peent.r square Each arcmeasurement second. This takes method a few has seconds been used and sky surveys. For measurements to be taken, the instrument was fixed to a tripod containing a bubble globallydisplays forthe darksky brightness sky surveys. in visualFor measurements magnitudes pe tor besquare taken, arc the second. instrument This method was fixed has to been a tripod used level, so it can point to zenith when fixed perpendicularly. The manufacturer suggests discarding the containingglobally for a darkbubble sky level, surveys. so it For can measurements point to zenith to when be taken, fixed the perpendicularly. instrument was The fixed manufacturer to a tripod first couple of measurements as the sensor is having a “cold start” [56]. As a result, measurements suggestscontaining discarding a bubble thelevel, first so couple it can ofpoint measurements to zenith when as the fixed sensor perpendicularly. is having a “cold The start” manufacturer [56]. As a were recorded after the third measurement. Information found in previous surveys [43,44] suggest result,suggests measurements discarding the were first recordedcouple of aftermeasurements the third measurement.as the sensor is Information having a “cold found start” in [56].previous As a that the accuracy of the instrument is high on the first decimal digit and lower on the second. This was surveysresult, measurements [43,44] suggest were that therecorded accuracy after of thethe inst thirdrument measurement. is high on theInformation first decimal found digit in and previous lower confirmed as successive readings from the instrument, with no factors changing in the meantime, onsurveys the second. [43,44] suggestThis was that confirmed the accuracy as ofsuccessive the instrument readings is high from on the the instrument,first decimal with digit noand factors lower showed variability in the second digit. As a result, three successive measurements of the same area changingon the second. in the This meantime, was confirmed showed asvariability successive in thereadings second from digit. the As instrument, a result, threewith successiveno factors were averaged and rounded to nearest 0.05 each time. The zenithal measurement of the astronomical measurementschanging in the of meantime,the same area showed were variabilityaveraged and in therounded second to nearestdigit. As 0.05 a result,each time. three The successive zenithal site in Parnon averaged at 21.55 visual magnitudes per square arc second. The site was also assessed measurementmeasurements of of the the astronomical same area were site averagedin Parnon and averaged rounded at 21.55 to nearest visual 0.05 magnitudes each time. per The square zenithal arc second.measurement The site of wasthe astronomical also assessed site visually in Parnon based averaged on the Bortle at 21.55 scale. visual According magnitudes to Bortle’s per square original arc second. The site was also assessed visually based on the Bortle scale. According to Bortle’s original Sustainability 2019, 11, 5963 17 of 24

Sustainabilityvisually based 2019, on11, x the FOR Bortle PEER REVIEW scale. According to Bortle’s original scale description [57], the area 17 of of the 24 astronomical site was judged to be of class 3. More specifically, the following are examples of Bortle’s scaledescription description that were[57], foundthe area to of match the astronomical (Figure 19): site was judged to be of class 3. More specifically, the following are examples of Bortle’s description that were found to match (Figure 19): Some indication of light pollution along the horizon but dark overhead • • SomeThe Milky indication Way appearsof light pollution complex along the horizon but dark overhead • • TheM22 Milky object Way visible appears with thecomplex naked eye •• M22Objects object such visible as telescopes with the becomenaked eye vaguely apparent at a distance of 10 m. •• Objects such as telescopes become vaguely apparent at a distance of 10 m.

Figure 19. AA simulation simulation of Bortle’s classes by skyglow project [58]. [58]. 4.3. Identifying Light Pollution Sources: Qualitative Tripoli Lighting Survey 4.3. Identifying Light Pollution Sources: Qualitative Tripoli Lighting Survey The largest city that is closest to the area of interest is Tripoli. With a population of 31,000, Tripoli The largest city that is closest to the area of interest is Tripoli. With a population of 31,000, Tripoli is an important commercial hub for the whole area and the capital of Peloponnese. Conducting a is an important commercial hub for the whole area and the capital of Peloponnese. Conducting a full- full-scale survey in Tripoli was outside the scope of this research work, however a sample qualitative scale survey in Tripoli was outside the scope of this research work, however a sample qualitative survey in parts of the city provided some useful information on the lighting installation of the city. survey in parts of the city provided some useful information on the lighting installation of the city. A A walkthrough of the city was performed, and photographs of the most common streetlights were walkthrough of the city was performed, and photographs of the most common streetlights were taken. taken. The main observations made were the following: The main observations made were the following: The city of Tripoli still uses older technology lighting (high pressure sodium and mercury lamps) •• The city of Tripoli still uses older technology lighting (high pressure sodium and mercury lamps) forfor most most of of its its streetlights streetlights (Figure (Figure 20a,b).20a,b). Lack of maintenance is evident with many luminaires in bad condition with missing parts •• Lack of maintenance is evident with many luminaires in bad condition with missing parts (Figure 20c).(Figure 20c). • SomeSome lighting lighting malpractices exist such as upward floodlightsfloodlights with reflectors,reflectors, whichwhich supposedlysupposedly • havehave superior superior aesthetics aesthetics but but actually actually contribute significantly significantly to light pollution (Figure 2020d).d).

AsAs a a result, result, it it is is expected expected that that the the city city of of Tripoli Tripoli will soon be in need of an upgrade for its lighting installation.installation. It It is is important important that that this this upgrade upgrade will will ta takeke place in a way that will decrease levels ofof lightlight pollutionpollution and and the the possible possible founding of a dark sky park in the vicinity would be a significantsignificant factorfactor toto pushpush for for dark dark sky sky friendly friendly lighting. lighting.

(a) (b) Sustainability 2019, 11, x FOR PEER REVIEW 17 of 24

scale description [57], the area of the astronomical site was judged to be of class 3. More specifically, the following are examples of Bortle’s description that were found to match (Figure 19): • Some indication of light pollution along the horizon but dark overhead • The Milky Way appears complex • M22 object visible with the naked eye • Objects such as telescopes become vaguely apparent at a distance of 10 m.

Figure 19. A simulation of Bortle’s classes by skyglow project [58].

4.3. Identifying Light Pollution Sources: Qualitative Tripoli Lighting Survey The largest city that is closest to the area of interest is Tripoli. With a population of 31,000, Tripoli is an important commercial hub for the whole area and the capital of Peloponnese. Conducting a full- scale survey in Tripoli was outside the scope of this research work, however a sample qualitative survey in parts of the city provided some useful information on the lighting installation of the city. A walkthrough of the city was performed, and photographs of the most common streetlights were taken. The main observations made were the following: • The city of Tripoli still uses older technology lighting (high pressure sodium and mercury lamps) for most of its streetlights (Figure 20a,b). • Lack of maintenance is evident with many luminaires in bad condition with missing parts (Figure 20c). • Some lighting malpractices exist such as upward floodlights with reflectors, which supposedly have superior aesthetics but actually contribute significantly to light pollution (Figure 20d). As a result, it is expected that the city of Tripoli will soon be in need of an upgrade for its lighting installation. It is important that this upgrade will take place in a way that will decrease levels of light Sustainabilitypollution2019 and, 11, the 5963 possible founding of a dark sky park in the vicinity would be a significant18 factor of 24 to push for dark sky friendly lighting.

Sustainability 2019, 11, x FOR PEER(a REVIEW) (b) 18 of 24

(c) (d)

FigureFigure 20. 20.(a) (Higha) High pressure pressure sodium sodium streetlights streetlights and and (b) ( band) and high high pressure pressure mercury mercury lamps lamps installed installed in in Tripoli.Tripoli. (c) (Luminairec) Luminaire with with former former high high pressure pressure mercur mercuryy lamps lamps turned turned into into CFL CFL with with plastic plastic covers covers missingmissing and and (d)( dand) and floodlights floodlights aiming aiming upwards upwards with with reflec reflectorstors for for reflecting reflecting ba backck the the light light causing causing increasedincreased light light pollution. pollution.

5. Discussion5. Discussion TheThe size size of ofthe the area area to tobe beprotected protected is isa very a very significant significant factor factor that that affects affects other other steps steps of of the the applicationapplication including including the the lighting lighting inventory survey.survey. As As a minimum,a minimum, part part of the of areathe thatarea willthat be will selected be selectedshould should belong belong to an alreadyto an already designated designated area (naturalarea (natural protection protection or astronomical or astronomical site). site). Large Large areas areaspresent present management management diffi cultiesdifficulties while while small small areas mayareas not may make not their make case their as acase site as worthy a site ofworthy protection. of protection.Local geography Local geography should be should taken intobe taken account into (such account as mountains, (such as mountains, lakes, etc.) lakes, as well etc.) as as settlements. well as settlements.However, However, the existence the ofexistence settlement of settlement is in no way is in incompatible. no way incompatible. Also, a very Also, important a very important factor to be factortaken to intobe taken account into is account legal status is legal and status whether and more whether than more one localthan governmentone local government entity is involved entity is in involvedthe area. in Everythe area. protected Every protected site should site have should a clear have scope a clear of protectionscope of protection that can typicallythat can typically be of natural be of protectionnatural protection or astronomical or astronom significance.ical significance. Sites can haveSites acan mixed have scope, a mixed which scope, is often which the is case, often but the one case,scope but mayone scope be considered may be considered primary and primary will be an usedd will for be most used of for the most publicity. of the publicity. ByBy examining examining the theNatura Natura 2000 2000protected protected area over arealaid overlaid onto a detailed onto a detailed light pollution light pollution map (Figure map 21a),(Figure it is evident21a), it isthat evident the whole that the area whole is located area is in located a dark inblue a dark zone blue meaning zone meaning it has appropriate it has appropriate skies. Therefore,skies. Therefore, all the protected all the protected area is a candidate area is a candidate area concerning area concerning the astronomy the astronomy aspect in respect aspect in to respectdark skies.to dark However, skies. However,astronomical astronomical activities activities in the ar inea the are area largely are largely confined confined to the to thelocation location of ofthe the astronomicalastronomical site. site. The The on-site on-site light light (luminance, (luminance, illu illuminance,minance, light light spectrum, spectrum, etc.) etc.) and and light light pollution pollution measurementsmeasurements (skyglow, (skyglow, sky sky brightness, brightness, etc.) etc.) verify verify the the corresponding corresponding result. result. In Inorder order to tostudy study the the geographicalgeographical location location of of the variousvarious zones, zones, we we overlaid overlaid a detailed a detailed map ofmap the zonesof the with zones the with astronomy the astronomyobserving observing site as noted site with as noted a red with dot (Figure a red dot 21b). (Figure It is obvious 21b). It that is obvious the astronomical that the astronomical site lies well insidesite lies well inside the Natura 2000 area but just outside the 3.IV protected area. The 3.IV protected area is protected due to rare endemic flora of the Parnon ridge. Furthermore, the single absolute protection area (2.Ι) is not very far away from the astronomical site and lies close to the Malevi monastery which is economically connected to the surveyed area around Agios Petros village. This area is extremely important due to the forests of Juniperus drupacea, a species of juniper native to the Eastern Mediterranean that grows on rocky sites from 800 to 1700 m altitude. According to Greek Law 121D/1980 this area has been declared a conserved natural monument. Thus, an area that encompasses the astronomical site, part of region 3.IV, and all of region 2.I is proposed as the basis for the first phase of declaring a dark sky park. The reasons are as follows: • It is a relatively small area that will be easier to manage initially, and all parts belong to the same zone of financial influence. • It comprises two different protection scopes (flora and astronomy) which make for a significant portfolio. • It comprises the especially important 2.I zone. Sustainability 2019, 11, 5963 19 of 24

the Natura 2000 area but just outside the 3.IV protected area. The 3.IV protected area is protected due to rare endemic flora of the Parnon ridge. Furthermore, the single absolute protection area (2.I) is not very far away from the astronomical site and lies close to the Malevi monastery which is economically connected to the surveyed area around Agios Petros village. This area is extremely important due to the forests of Juniperus drupacea, a species of juniper native to the Eastern Mediterranean that grows on rocky sites from 800 to 1700 m altitude. According to Greek Law 121D/1980 this area has been declared a conserved natural monument. Thus, an area that encompasses the astronomical site, part of region 3.IV, and all of region 2.I is proposed as the basis for the first phase of declaring a dark sky park. The reasons are as follows: It is a relatively small area that will be easier to manage initially, and all parts belong to the same • zone of financial influence. SustainabilityIt comprises 2019, 11, x FOR two PEER diff REVIEWerent protection scopes (flora and astronomy) which make 19 for of 24 a • Sustainabilitysignificant 2019, 11 portfolio., x FOR PEER REVIEW 19 of 24 • It is the area closest to light pollution sources (large cities and highways), therefore it is of more It comprises the especially important 2.I zone. • imminent danger. • ItIt is the area closest to light pollution sources (large(large cities and highways), therefore itit isis ofof moremore • Finally,imminentimminent the danger. danger. proposed area appears in the large dotted circle in Figure 22. Finally,Finally, the proposed area appears in the large dotted circlecircle inin FigureFigure 2222..

(a) (b) Figure 21. (a) The Natura 2000 protected(a) area (black outline) overlaid over a detailed( blight) pollution mapFigureFigure of 21. Parnon ((aa)) The The area Natura Natura and ( b2000 ) Natura protected 2000 border area (black map outline)outlin in detaile) overlaid with astronomy overover aa detaileddetailed site noted lightlight by pollutionpollution the red dot.mapmap of Parnon areaarea andand ( b(b)) Natura Natura 2000 2000 border border map map in in detail detail with with astronomy astronomy site site noted noted by the by redthe dot. red dot.

Figure 22. ProposedProposed area area to to be be included included in th thee initial dark sky park procedure. Figure 22. Proposed area to be included in the initial dark sky park procedure. LastLast but but not not least, an important factor in the long-term success and sustainabilitysustainability of aa plannedplanned dark sky park will be a plan of environmental education programs that will include light pollution dark Lastsky parkbut not will least, be a anplan important of environmental factor in the education long-term programs success thatand willsustainability include light of a pollution planned anddark dark sky skies.park willCitizens be a andplan visitors of environmental should be in educationformed about programs the importance that will ofinclude protecting light dark pollution skies and darkthe suggested skies. Citizens measures and visitorsto prev entshould light be pollution. informed Protected about the areaimportance management of protecting agencies dark already skies carryand the out suggested daytime educationmeasures activitiesto prevent and light it ispollution. proposed Protected that such area programs management expand agencies to include already night activitiescarry out daytimesuch as telescopeeducation observationsactivities and and it is prlearningoposed the that constellations. such programs Especially expand to in include the case night of visitorsactivities from such urban as telescope areas, the observations view of truly and dark learning skies hasthe beenconstellations. very effective Especially in raising in theawareness case of aboutvisitors the from protection urban areas, of night the viewskies. ofThe truly already dark skiesexisting has astronomical been very effective activities in raisingin mount awareness Parnon shouldabout the be encouragedprotection of and night aimed skies. to takeThe alreadythe form existing of astrotourism astronomical which activities can assist in inmount the financial Parnon sustainabilityshould be encouraged of the area. and Local aimed authorities to take the and form businesses of astrotourism can expect which financial can assist gains in fromthe financial people visitingsustainability the area of notthe only area. for Local its daytime authorities beauty and but businesses also for its can dark expect skies. financial It is expected gains thatfrom financial people motivesvisiting thewill area urge not local only authorities for its daytime and businesses beauty but to also participate for its dark in the skies. night It issky expected protection that effort. financial motives will urge local authorities and businesses to participate in the night sky protection effort. 6. Conclusions 6. ConclusionsLight pollution poses a significant threat to our health, the dark skies, and the natural environment.Light pollution This fact poses is backed a significant by extensive threat rese toarch our in thehealth, fields the of medarkdicine, skies, astronomy, and the andnatural the environment. This fact is backed by extensive research in the fields of medicine, astronomy, and the Sustainability 2019, 11, 5963 20 of 24 and dark skies. Citizens and visitors should be informed about the importance of protecting dark skies and the suggested measures to prevent light pollution. Protected area management agencies already carry out daytime education activities and it is proposed that such programs expand to include night activities such as telescope observations and learning the constellations. Especially in the case of visitors from urban areas, the view of truly dark skies has been very effective in raising awareness about the protection of night skies. The already existing astronomical activities in mount Parnon should be encouraged and aimed to take the form of astrotourism which can assist in the financial sustainability of the area. Local authorities and businesses can expect financial gains from people visiting the area not only for its daytime beauty but also for its dark skies. It is expected that financial motives will urge local authorities and businesses to participate in the night sky protection effort.

6. Conclusions Light pollution poses a significant threat to our health, the dark skies, and the natural environment. This fact is backed by extensive research in the fields of medicine, astronomy, and the environmental sciences [59–67]. It is imperative to push for measures against light pollution because research regarding its impact on human health has helped make headlines worldwide. The imminent switch to LED lighting for most of the exterior lighting globally needs to take place in a way that reduces light pollution using full-cutoff luminaires of proper luminous intensity and warm, if not amber, color temperature [24]. Greece has not yet made a complete LED transition, which makes the next few years particularly crucial regarding the course of light pollution and whether it will significantly increase or not. The IDA’s Dark Dky Place (and more importantly park) program [30] is a very successful international program that has helped protect areas from light pollution as well as communicated the need for dark sky protection to the public all around the world. A dark sky park designation has helped protected areas around the world push for measures against light pollution which is not easy as proven by the experience of dark sky activists worldwide. This program would ideally suit the characteristics of Greece with its rich natural environment and darker skies as compared to most of Europe. Mount Parnon was identified as an ideal place for the establishment of Greece’s first dark sky park using on-site measurements and lighting equipment survey. Mount Parnon is an extremely important area as a significant natural reserve as well as a significant astronomical site. Regarding astronomy, mount Parnon has been a hub of Greek amateur astronomers for the last couple of decades. It has proven suitable for astronomical observations and is widely known all over Greece thanks to the three annual amateur astronomer gatherings that have been organized there. Skies in Parnon are as dark as one can possibly have in Europe. As a natural site, the flora of mount Parnon is extremely important and at least one area is of critical importance while areas for the protection of both fauna and flora exist. These factors prove not only its suitability but also its importance for conservation while the fact that the site is already popular lays an important foundation regarding the sustainability of a potential dark sky park. Current measurements show that mount Parnon is a very dark site (SQM measurements of 21.55 mag/arcsec2) but its proximity to large cities and important highways as well as small communities with significant tourist potential pose a threat to its dark skies. Light pollution is already prominent near the horizon and global experience has shown that this level of light pollution tends to increase. Existing lighting installations both in the nearby area as well as nearby cities are old, unmaintained, and with no sign of any plan. Furthermore, the spectrum of existing luminaires is not appropriate as the G-index failed significantly compared to the newly defined lower limits [24]. Outdoor luminaires used in the area aim a significant percentage of light towards the sky, however the relatively small number of villages and lack of streetlights in between villages limit current levels of light pollution. General lighting levels were low, with minimum private lighting. However, a malpractice was identified (Karyes monument), and actions should be performed in order to minimize the light levels and re-aim the luminaires. It is expected that lighting installations will soon be retrofitted or upgraded, possibly to Sustainability 2019, 11, 5963 21 of 24

LED, because they are old and this process is imminent all over the country. Retrofitting or upgrading should take place in a way that reduces light pollution visible in the horizon and avoids a possibly catastrophic switch to blue-rich LEDs which, as shown by research, significantly increase the levels of skyglow. High energy costs due to light design mistakes can significantly assist in convincing a proper lighting upgrade since the lighting survey detected that lighting of specific installations such as artefacts consume significantly more power than they should. Dark skies of equal status to Parnon have been identified in Greek mountains in Central Greece and West Macedonia. A number of important astronomical sites already exist in Greece as well as a number of protected areas all around the country either as Natura 2000 sites or sites of national protection. It is expected that many areas in Greece will prove to have similar suitability to Parnon and should endeavor to achieve a dark sky park designation. Mount Parnon, as the most prominent example, should have an application filed with the IDA in the coming years. A successful outcome will pave the way for more dark sky places to follow. In order for a successful application to be filed, the proper steps need to be taken. These include forming a consortium of organizations based around a management agency and the Greek chapter of the International Dark Sky Association with participation of the supporting organizations identified in this work (local astronomy clubs, mountaineering clubs, cultural clubs, businesses, etc.). The consortium should prepare an application file, a significant part of which can be based on this work since it is a requirement of the IDA process (lighting inventory, geographical borders, protection scope, proposed lighting changes, identified partners, outreach plan, etc.).

Author Contributions: Conceptualization, A.P.; methodology, A.P. and L.T.D.; measurements, A.P. and L.T.D.; formal analysis, A.P.; investigation, A.P.; data curation, A.P.; writing—original draft preparation, A.P.; writing—review and editing, A.P. and L.T.D.; visualization, A.P.; supervision, L.T.D. Funding: This research received no external funding. Conflicts of Interest: The authors declare no conflicts of interest.

Abbreviations—List of Abbreviations and Acronyms

CCT correlated color temperature IR infrared CFL compact fluorescent lamp LED light emitting diode DSLR digital single lens reflex EU European Union HPM high pressure mercury lamp SCI sites of community importance SPA special protected area IDA International Dark Sky Association SQM sky quality meter

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