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@ SOUTHWEST FOREST SERVICE Forest and R U. S.DEPARTMENT OF AGRICULTURE P.0. BOX 245, BERKELEY, CALIFORNIA 94701 Experime Computation of times of sunrise, sunset, and twilight in or near mountainous terrain Bill 6. Ryan Times of sunrise and sunset at specific mountain- ous locations often are important influences on for- estry operations. The change of heating of slopes and terrain at sunrise and sunset affects temperature, air density, and wind. The times of the changes in heat- ing are related to the times of reversal of slope and valley flows, surfacing of strong winds aloft, and the USDA Forest Service penetration inland of the sea breeze. The times when Research NO& PSW- 322 these meteorological reactions occur must be known 1977 if we are to predict fire behavior, smolce dispersion and trajectory, fallout patterns of airborne seeding and spraying, and prescribed burn results. ICnowledge of times of different levels of illumination, such as the beginning and ending of twilight, is necessary for scheduling operations or recreational endeavors that require natural light. The times of sunrise, sunset, and twilight at any particular location depend on such factors as latitude, longitude, time of year, elevation, and heights of the surrounding terrain. Use of the tables (such as The 1 Air Almanac1) to determine times is inconvenient Ryan, Bill C. because each table is applicable to only one location. 1977. Computation of times of sunrise, sunset, and hvilight in or near mountainous tersain. USDA Different tables are needed for each location and Forest Serv. Res. Note PSW-322, 4 p. Pacific corrections must then be made to the tables to ac- Southwest Forest and Range Exp. -
ESSENTIALS of METEOROLOGY (7Th Ed.) GLOSSARY
ESSENTIALS OF METEOROLOGY (7th ed.) GLOSSARY Chapter 1 Aerosols Tiny suspended solid particles (dust, smoke, etc.) or liquid droplets that enter the atmosphere from either natural or human (anthropogenic) sources, such as the burning of fossil fuels. Sulfur-containing fossil fuels, such as coal, produce sulfate aerosols. Air density The ratio of the mass of a substance to the volume occupied by it. Air density is usually expressed as g/cm3 or kg/m3. Also See Density. Air pressure The pressure exerted by the mass of air above a given point, usually expressed in millibars (mb), inches of (atmospheric mercury (Hg) or in hectopascals (hPa). pressure) Atmosphere The envelope of gases that surround a planet and are held to it by the planet's gravitational attraction. The earth's atmosphere is mainly nitrogen and oxygen. Carbon dioxide (CO2) A colorless, odorless gas whose concentration is about 0.039 percent (390 ppm) in a volume of air near sea level. It is a selective absorber of infrared radiation and, consequently, it is important in the earth's atmospheric greenhouse effect. Solid CO2 is called dry ice. Climate The accumulation of daily and seasonal weather events over a long period of time. Front The transition zone between two distinct air masses. Hurricane A tropical cyclone having winds in excess of 64 knots (74 mi/hr). Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Mesosphere The atmospheric layer between the stratosphere and the thermosphere. -
The Golden Hour Refers to the Hour Before Sunset and After Sunrise
TheThe GoldenGolden HourHour The Golden Hour refers to the hour before sunset and after sunrise. Photographers agree that some of the very best times of day to take photos are during these hours. During the Golden Hours, the atmosphere is often permeated with breathtaking light that adds ambiance and interest to any scene. There can be spectacular variations of colors and hues ranging from subtle to dramatic. Even simple subjects take on an added glow. During the Golden Hours, take photos when the opportunity presents itself because light changes quickly and then fades away. 07:14:09 a.m. 07:15:48 a.m. Photographed about 60 seconds after previous photo. The look of a scene can vary greatly when taken at different times of the day. Scene photographed midday Scene photographed early morning SampleSample GoldenGolden HourHour photosphotos Top Tips for taking photos during the Golden Hours Arrive on the scene early to take test shots and adjust camera settings. Set camera to matrix or center-weighted metering. Use small apertures for maximizing depth-of-field. Select the lowest possible ISO. Set white balance to daylight or sunny day. When lighting is low, use a tripod with either a timed shutter release (self-timer) or a shutter release cable or remote. Taking photos during the Golden Hours When photographing the sun Don't stare into the sun, or hold the camera lens towards it for a very long time. Meter for the sky but don't include the sun itself. Composition tips: The horizon line should be above or below the center of the scene. -
Exploring Solar Cycle Influences on Polar Plasma Convection
Comparison of Terrestrial and Martian TEC at Dawn and Dusk during Solstices Angeline G. Burrell1 Beatriz Sanchez-Cano2, Mark Lester2, Russell Stoneback1, Olivier Witasse3, Marco Cartacci4 1Center for Space Sciences, University of Texas at Dallas 2Radio and Space Plasma Physics, University of Leicester 3European Space Agency, ESTEC – Scientific Support Office 4Istituto Nazionale di Astrofisica, Istituto di Astrofisica e Planetologia Spaziali 52nd ESLAB Symposium Outline • Motivation • Data and analysis – TEC sources – Data selection – Linear fitting • Results – Martian variations – Terrestrial variations – Similarities and differences • Conclusions Motivation • The Earth and Mars are arguably the most similar of the solar planets - They are both inner, rocky planets - They have similar axial tilts - They both have ionospheres that are formed primarily through EUV and X- ray radiation • Planetary differences can provide physical insights Total Electron Content (TEC) • The Global Positioning System • The Mars Advanced Radar for (GPS) measures TEC globally Subsurface and Ionosphere using a network of satellites and Sounding (MARSIS) measures ground receivers the TEC between the Martian • MIT Haystack provides calibrated surface and Mars Express TEC measurements • Mars Express has an inclination - Available from 1999 onward of 86.9˚ and a period of 7h, - Includes all open ground and allowing observations of all space-based sources locations and times - Specified with a 1˚ latitude by 1˚ • TEC is available for solar zenith longitude resolution with error estimates angles (SZA) greater than 75˚ Picardi and Sorge (2000), In: Proc. SPIE. Eighth International Rideout and Coster (2006) doi:10.1007/s10291-006-0029-5, 2006. Conference on Ground Penetrating Radar, vol. 4084, pp. 624–629. -
Insider Tips
It’s no secret that North Lake Tahoe has some of the most gorgeous sunsets on the west coast, but did you know that winter is actually the best time to watch the sunset? The shoreline of North Lake Tahoe is the perfect place to watch the sky light up, so follow along and get your cameras ready! What Is It? Fun Facts Year-round, North Lake Tahoe is home to the most awe- • Alpenglow happens when light is reflected off airborne inspiring sunsets featuring breathtaking cotton candy colored precipitation and ice crystals in the lower atmosphere skies. In winter, the signature snowy scenery and glittering and technically is only visible after sunset or before waters add even more beauty to the region’s sunsets for a sunrise. The term “alpenglow” dates back to 19th can’t-miss viewing experience. century Germany to describe this unique phenomenon. Where Can I Find It? If You Like This, You’ll Love: North Lake Tahoe’s beaches are some of the best places to Other great spots for winter lakeside sunsets in North Lake catch stunning sunsets in the winter, from Commons Beach Tahoe include: in Tahoe City to The Hyatt Regency Lake Tahoe’s beach in • Hidden Beach in Incline Village Incline Village and everywhere in between. • Donner Summit in Truckee Because sunsets happen earlier during winter months, these beaches also offer the perfect jumping off point to enjoy • Moon Dunes Beach in Tahoe Vista dinner during or after a sunset. Try these different restaurants • Speedboat Beach in Crystal Bay for the perfect post-sunset meal: In Tahoe City and Commons Beach Insider Tips • Christy Hill, Sunnyside Restaurant & Lodge, Jake’s On • Because the sun goes down earlier in the winter, visitors The Lake, or Wolfdale’s Cuisine Unique can enjoy the sunset before, or during, dinner without In Kings Beach and Carnelian Bay having to stay up late. -
Planit! User Guide
ALL-IN-ONE PLANNING APP FOR LANDSCAPE PHOTOGRAPHERS QUICK USER GUIDES The Sun and the Moon Rise and Set The Rise and Set page shows the 1 time of the sunrise, sunset, moonrise, and moonset on a day as A sunrise always happens before a The azimuth of the Sun or the well as their azimuth. Moon is shown as thick color sunset on the same day. However, on lines on the map . some days, the moonset could take place before the moonrise within the Confused about which line same day. On those days, we might 3 means what? Just look at the show either the next day’s moonset or colors of the icons and lines. the previous day’s moonrise Within the app, everything depending on the current time. In any related to the Sun is in orange. case, the left one is always moonrise Everything related to the Moon and the right one is always moonset. is in blue. Sunrise: a lighter orange Sunset: a darker orange Moonrise: a lighter blue 2 Moonset: a darker blue 4 You may see a little superscript “+1” or “1-” to some of the moonrise or moonset times. The “+1” or “1-” sign means the event happens on the next day or the previous day, respectively. Perpetual Day and Perpetual Night This is a very short day ( If further north, there is no Sometimes there is no sunrise only 2 hours) in Iceland. sunrise or sunset. or sunset for a given day. It is called the perpetual day when the Sun never sets, or perpetual night when the Sun never rises. -
Atmospheric Refraction
International Young Naturalists’ Tournament 4. Sunset Serbian team Regional Center For Talented Youth 4. Sunset The visible Sun disk touches the horizon and after a particular time interval disappears behind the horizon. What is the duration of this time interval? Explain the optical phenomena observed during a sunset. SUNSET Sunset (sundown) - daily disappearance of the Sun below the western horizon, as a result of Earth's rotation In astronomy : the time of sunset - moment when the trailing edge of the Sun's disk disappears below the horizon ANGULAR VELOCITY OF THE SUN • angularthe angle speed by which for one an complete object spins rotation in a certain is given time as: - its rotation rate t = 23h 54 min 4s ANGULAR VELOCITY - orthogonal component- ω ϕ DURATION OF SUNSET •equation for the duration of sunset: DURATION OF SUNSET • The fastest sunset at the time of the equinoxes (March 21 and September 23 • The slowest sunset at the time of solstice (around 21 June and 21 December) DURATION OF SUNSET • The fastest sunset - 2 minutes 47 sec • The slowest sunset - 3 min 23 sec • At the equator, between 128 and 142 sec (2 min. 8 sec and 2 min. 22 sec) DURATION OF SUNSET City Duration of sunset Latitude Beijing 167 s 39.92° Belgrade 183.6 s 44.82° Paris 198 s 48.86° London 209.3 s 51.51° Moscow 231.5 s 55.75 ° Light scattering Reflection Refraction LIGHT SCATTERING • caused by small particles and molecules in the atmosphere • scattered rays go off in many directions RAYLEIGH SCATTERING • Rayleigh scattering - elastic scattering of light • Blue light from the sun is scattered more than red LAW OF REFLECTION DIFFUSE REFLECTION • It occurs when a rough surface causes reflected rays to travel in different directions ATMOSPHERIC REFRACTION • the shift in apparent direction of a celestial object caused by the refraction of light rays as they pass through Earth’s atmosphere MORE OPTICAL PHENOMENA Twilight Wedge Belt of Venus Earth’s shadow Afterglow Alpenglow CONCLUSION During the sunset: 1. -
The Blue Hour‐ by Dennis Arculeo
THE April 2019 May 16th‐ End of Year Compeon Building G Sung Harbor 8 PM th May 4 ‐ Model Shoot ‐ Mayr Studio ‐ Staten Island Camera Club Meet‐Up reserve a seat @: hps://www.meetup.com/ Staten‐Island‐camera‐club/events/259170884/ spaces are limited. May 16th‐ End of Year Compeon ‐ Harbor Room 8:00PM Image of the Year Selecon ‐ Judge Al Brown. June 6th - Annual Awards Dinner - Real Madrid Restaurant - All are welcome - Bring a Friend - Paid Reservation is a must! June 8th Saturday Governors House Meet‐Up reserve a seat @: reserve a seat @: hps://www.meetup.com/Staten‐Island‐camera‐ club/events/ spaces are limited. Well, the End of Year Compeon is almost here. On that For those who aended in the past the menu is the same. night we will decide the Images of the Year. So come on down on May 16th.. Color and Mono Digital Images and You can secure your reservaon with a $45.00 per person pay‐ Prints will compete for the coveted awards in each of their ment on May 16that this month’s End of the Year Compe‐ respecve categories. You can enter any 4 Color or Mono on. Please bring a check payable to Staten Island Camera Club. Digital and or Print that you competed with this season. If you are not aending the End of Year Compeon, but would Here is the low down on the Awards Dinner being held on like to aend the dinner please mail your check to: Thursday June 6th, 2019. Barbara M. Hoffman at 323 Stobe Avenue, SI, NY 10306. -
When the Earth Was Young in This Issue
WESTCHESTER AMATEUR ASTRONOMERS August 2014 Illustration Credit: Simone Marchi (SwRI), SSERVI, NASA When the Earth Was Young Four billion years ago, our Solar System was a dangerous shooting gallery of large and dangerous rocks and ice chunks. Recent examination of lunar and Earth bombardment data in- In This Issue . dicate that the entire surface of the Earth underwent piecemeal upheavals, creating a battered world with no remaining famil- pg. 2 Events For August iar landmasses. The rain of devastation made it difficult for pg. 3 Almanac any life to survive. Oceans thought to have formed during this pg. 4 Into the Belly of the Beast: The epoch would boil away after particularly heavy impacts, only to reform again. The above artist's illustration depicts how ATLAS Detector Earth might have looked during this epoch, with circular im- pg. 10 The Invisible Shield of our Sun pact features dotting the daylight side, and hot lava flows visi- ble in the night. Credit: APOD SERVING THE ASTRONOMY COMMUNITY SINCE 1986 1 WESTCHESTER AMATEUR ASTRONOMERS August 2014 Events for August 2014 Kopernik AstroFest 2014 WAA Lectures This event will be held at the Kopernik Observatory Lienhard Lecture Hall, & Science Education Center – Vestal, NY on Octo- th th Pace University Pleasantville, NY ber 24 and 25 , 2014. Presented by the The Ko- As usual, there will be no WAA lecture for the month pernik Astronomical Society, the Astrofest will fea- of August. Our Lecture series will resume on Septem- ture astronomy workshops, solar viewing, observa- ber 12th. During the Fall we have tentatively scheduled tory tours and speakers from the amateur and pro- presentations by Victor Miller on the Galileo Jupiter fessional communities as well as observing at night. -
Photography Glossary
PHOTOGRAPHY GLOSSARY This photography terms glossary is what you’ll need to know in order to become a walking encyclopedia and learn how to take amazing and effective photographs. Please take advantage of it Aperture Aperture is the opening through which light passes through the lens to enter the camera. Its size can be modified to control how much light reaches the sensor or negative film. The diameter of the aperture, also known as the F-stop, affects the exposure and depth of field. Blue Hour Blue hour is the short period of time before sunrise or after sunset when the sun is just below the horizon. Indirect sunlight is evenly diffused and takes on a blue shade. The duration on the blue hour varies depending on the location, but generally lasts less than an hour. Candid candid is a portrait taken while the subject is not posing. This can be achieved either by capturing a subject unaware of the photographer’s presence or by introducing motion and surprising the model during a photoshoot. This kind of portrait photography is highly popular in street photography and is becoming more relevant in formal environments such as weddings. Composition Composition is the manner in which elements are positioned within a photo. It is considered one of the most important components of an image, as it allows the photographer to guide the viewer’s eye across the image towards the main subject. Contrast Contrast defines the range of tonal difference between the shadows and lights of an image. As the contrast becomes higher it emphasizes these variations, resulting in stronger textures and colors. -
Mary W. Helms Source: Anthropos, Bd
Before the Dawn. Monks and the Night in Late Antiquity and Early Medieval Europe Author(s): Mary W. Helms Source: Anthropos, Bd. 99, H. 1. (2004), pp. 177-191 Published by: Anthropos Institute Stable URL: http://www.jstor.org/stable/40466312 . Accessed: 29/07/2013 13:48 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Anthropos Institute is collaborating with JSTOR to digitize, preserve and extend access to Anthropos. http://www.jstor.org This content downloaded from 152.13.249.96 on Mon, 29 Jul 2013 13:48:56 PM All use subject to JSTOR Terms and Conditions H Anthropos IT] 99.2004:177-191 Beforethe Dawn Monksand theNight in Late Antiquityand EarlyMedieval Europe MaryW. Helms Abstract.- Early European monkswere preoccupiedwith the and withformal rules and especiallyritual that night.They were quintessentialmen of the dark,for nocturns, definedand activatedfundamental tenets of faith by fartheir longest liturgical office, was conductedeach night, offices. in the blacknessof unlitchurches. In so monks throughcarefully organized liturgical virtually doing these not only rituallyanticipated the coming of the dawn but Foremostamong ideologicallycharged also, and especially,engaged withthe primordialcosmological monasticsettings and liturgical presentations were darknessthat preceded the original creation of Genesis. -
Night Photography December 2011
Night Photography December 2011 Max Lyons http://www.tawbaware.com Agenda ● Photography at different times of night ● Moon ● Stars ● Software and technology ● Tips, Tricks and Equipment Blue Hour ● Blue Hour: “The period of twilight each morning and evening where there is neither full daylight nor complete darkness. The time is considered special because of the quality of the light at this time of day." 35 minutes after sunset, sun about 7 degrees below horizon Twilight ● Twilight: “the period between sunset and sunrise during which there is natural light provided by the upper atmosphere, which receives direct sunlight and scatters part of it towards the earth's surface" Credit: Why Not a Duck / Wikimedia Commons Light After The Sun Sets ● Civil Twilight: Sun is 0 to 6 degrees below horizon ● Nautical Twilight: Sun is 6 to 12 degrees below horizon ● Astronomical Twilight: Sun is 12-18 degrees below horizon ● Night: Sun is more than 18 degrees below horizon Blue Hour ● Some of the best “sunset” shots happen after most of the photographers have packed up their gear and gone home! Top: 1 minute before sunset, sun on horizon Bottom: 30 minutes after sunset, sun about 6 degrees below horizon Blue Hour ● If conditions are right, clouds “light up” just after sunset 10 minutes after sunset, sun about 2 degrees below horizon Blue Hour ● Clouds take on pink glow just after sunset 10 minutes after sunset, sun about 2 degrees below horizon Blue Hour ● Twilight provides even, soft illumination...and the opportunity for longer exposures 15 minutes after sunset, sun about 3.5 degrees below horizon ISO 100, F11, 2 seconds Blue Hour ● Great time to shoot objects illuminated by artificial light: buildings, statues, monuments, etc.