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Planet Positions: 1 Planet Positions
Planet Positions: 1 Planet Positions As the planets orbit the Sun, they move around the celestial sphere, staying close to the plane of the ecliptic. As seen from the Earth, the angle between the Sun and a planet -- called the elongation -- constantly changes. We can identify a few special configurations of the planets -- those positions where the elongation is particularly noteworthy. The inferior planets -- those which orbit closer INFERIOR PLANETS to the Sun than Earth does -- have configurations as shown: SC At both superior conjunction (SC) and inferior conjunction (IC), the planet is in line with the Earth and Sun and has an elongation of 0°. At greatest elongation, the planet reaches its IC maximum separation from the Sun, a value GEE GWE dependent on the size of the planet's orbit. At greatest eastern elongation (GEE), the planet lies east of the Sun and trails it across the sky, while at greatest western elongation (GWE), the planet lies west of the Sun, leading it across the sky. Best viewing for inferior planets is generally at greatest elongation, when the planet is as far from SUPERIOR PLANETS the Sun as it can get and thus in the darkest sky possible. C The superior planets -- those orbiting outside of Earth's orbit -- have configurations as shown: A planet at conjunction (C) is lined up with the Sun and has an elongation of 0°, while a planet at opposition (O) lies in the opposite direction from the Sun, at an elongation of 180°. EQ WQ Planets at quadrature have elongations of 90°. -
Sun Tool Options
Sun Study Tools Sophomore Architecture Studio: Lighting Lecture 1: • Introduction to Daylight (part 1) • Survey of the Color Spectrum • Making Light • Controlling Light Lecture 2: • Daylight (part 2) • Design Tools to study Solar Design • Architectural Applications Lecture 3: • Light in Architecture • Lighting Design Strategies Sun Tool Options 1. Paper and Pencil 2. Build a Model 3. Use a Computer The first step to any of these options is to define…. Where is the site? 1 2 Sun Study Tools North Latitude and Longitude South Longitude Latitude Longitude Sun Study Tools North America Latitude 3 United States e ud tit La Sun Study Tools New York 72w 44n 42n Site Location The site location is specified by a latitude l and a longitude L. Latitudes and longitudes may be found in any standard atlas or almanac. Chart shows the latitudes and longitudes of some North American cities. Conventions used in expressing latitudes are: Positive = northern hemisphere Negative = southern hemisphere Conventions used in expressing longitudes are: Positive = west of prime meridian (Greenwich, United Kingdom) Latitude and Longitude of Some North American Cities Negative = east of prime meridian 4 Sun Study Tools Solar Path Suns Position The position of the sun is specified by the solar altitude and solar azimuth and is a function of site latitude, solar time, and solar declination. 5 Sun Study Tools Suns Position The rotation of the earth about its axis, as well as its revolution about the sun, produces an apparent motion of the sun with respect to any point on the altitude earth's surface. The position of the sun with respect to such a point is expressed in terms of two angles: azimuth The sun's position in terms of solar altitude (a ) and azimuth (a ) solar azimuth, which is the t s with respect to the cardinal points of the compass. -
Equatorial and Cartesian Coordinates • Consider the Unit Sphere (“Unit”: I.E
Coordinate Transforms Equatorial and Cartesian Coordinates • Consider the unit sphere (“unit”: i.e. declination the distance from the center of the (δ) sphere to its surface is r = 1) • Then the equatorial coordinates Equator can be transformed into Cartesian coordinates: right ascension (α) – x = cos(α) cos(δ) – y = sin(α) cos(δ) z x – z = sin(δ) y • It can be much easier to use Cartesian coordinates for some manipulations of geometry in the sky Equatorial and Cartesian Coordinates • Consider the unit sphere (“unit”: i.e. the distance y x = Rcosα from the center of the y = Rsinα α R sphere to its surface is r = 1) x Right • Then the equatorial Ascension (α) coordinates can be transformed into Cartesian coordinates: declination (δ) – x = cos(α)cos(δ) z r = 1 – y = sin(α)cos(δ) δ R = rcosδ R – z = sin(δ) z = rsinδ Precession • Because the Earth is not a perfect sphere, it wobbles as it spins around its axis • This effect is known as precession • The equatorial coordinate system relies on the idea that the Earth rotates such that only Right Ascension, and not declination, is a time-dependent coordinate The effects of Precession • Currently, the star Polaris is the North Star (it lies roughly above the Earth’s North Pole at δ = 90oN) • But, over the course of about 26,000 years a variety of different points in the sky will truly be at δ = 90oN • The declination coordinate is time-dependent albeit on very long timescales • A precise astronomical coordinate system must account for this effect Equatorial coordinates and equinoxes • To account -
Lecture 6: Where Is the Sun?
4.430 Daylighting Massachusetts Institute of Technology Christoph Reinhart Department of Architecture 4.430 Where is the sun? Building Technology Program Goals for This Week Where is the sun? Designing Static Shading Systems MIT 4.430 Daylighting, Instructor C Reinhart 1 1 MISC Meeting on group projects Reduce HDR image size via pfilt –x 800 –y 550 filne_name_large.pic > filename_small>.pic Note: pfilt is a Radiance program. You can find further info on pfilt by googeling: “pfilt Radiance” MIT 4.430 Daylighting, Instructor C Reinhart 2 2 Daylight Factor Hand Calculation Mean Daylight Factor according to Lynes Reinhart & LoVerso, Lighting Research & Technology (2010) Move into the building, design the facade openings, room dimensions and depth of the daylit area. Determine the required glazing area using the Lynes formula. A glazing = required glazing area A total = overall interior surface area (not floor area!) R mean = area-weighted mean surface reflectance vis = visual transmittance of glazing units = sun angle 3 ‘Validation’ of Daylight Factor Formula Reinhart & LoVerso, Lighting Research & Technology (2010) Graph of mean daylighting factor according to Lynes formula v. Radiance removed due to copyright restrictions. Source: Figure 5 in Reinhart, C. F., and V. R. M. LoVerso. "A Rules of Thumb Based Design Sequence for Diffuse Daylight." Lighting Research and Technology 42, no. 1 (2010): 7-32. Comparison to Radiance simulations for 2304 spaces. Quality control for simulations. LEED 2.2 Glazing Factor Formula Graph of mean daylighting factor according to LEED 2.2 v. Radiance removed due to copyright restrictions. Source: Figure 11 in Reinhart, C. F., and V. -
Solar Photovoltaic (PV) Site Assessment
Solar Photovoltaic (PV) Site Assessment Item Type text; Book Authors Franklin, Ed Publisher College of Agriculture, University of Arizona (Tucson, AZ) Download date 29/09/2021 11:10:49 Item License http://creativecommons.org/licenses/by-nc-sa/4.0/ Link to Item http://hdl.handle.net/10150/625447 az1697 August 2017 Solar Photovoltaic (PV) Site Assessment Dr. Ed Franklin Introduction An important consideration when installing a solar photovoltaic (PV) array for residential, commercial, or agricultural operations is determining the suitability of the site. A roof-top location for a residential application may have fewer options due to limited space (roof size), type of roofing material (such as a sloped shingle, or a flat roof), the orientation (south, east, or west), and roof-mounted structures such as vent pipe, chimney, heating & cooling units. A location with open space may utilize a ground-mount system or pole-mount system. Determining the physical location of a solar PV array is a critical step to optimize energy output performance of the system. The ideal location is where solar modules are exposed to full sunshine from sun up to sun down without worry about shade cast on the modules from trees, power poles, guide wires, vent pipes, or nearby buildings, or the changing location of the sun. In the Northern Hemisphere, solar PV arrays are oriented to the south toward the Equator. Over the course of a calendar year, the sun’s altitude (height) in the sky changes. For example, during the month of June, the sun reaches its highest point in the sky on June 21 at 12:00 noon (summer solstice), and the sun Figure 1. -
The Solar Resource
CHAPTER 7 THE SOLAR RESOURCE To design and analyze solar systems, we need to know how much sunlight is available. A fairly straightforward, though complicated-looking, set of equations can be used to predict where the sun is in the sky at any time of day for any location on earth, as well as the solar intensity (or insolation: incident solar Radiation) on a clear day. To determine average daily insolation under the com- bination of clear and cloudy conditions that exist at any site we need to start with long-term measurements of sunlight hitting a horizontal surface. Another set of equations can then be used to estimate the insolation on collector surfaces that are not flat on the ground. 7.1 THE SOLAR SPECTRUM The source of insolation is, of course, the sun—that gigantic, 1.4 million kilo- meter diameter, thermonuclear furnace fusing hydrogen atoms into helium. The resulting loss of mass is converted into about 3.8 × 1020 MW of electromagnetic energy that radiates outward from the surface into space. Every object emits radiant energy in an amount that is a function of its tem- perature. The usual way to describe how much radiation an object emits is to compare it to a theoretical abstraction called a blackbody. A blackbody is defined to be a perfect emitter as well as a perfect absorber. As a perfect emitter, it radiates more energy per unit of surface area than any real object at the same temperature. As a perfect absorber, it absorbs all radiation that impinges upon it; that is, none Renewable and Efficient Electric Power Systems. -
3. Calculating Solar Angles
3. Calculating Solar Angles These equations should be used keeping all of the angles in radians even though with some of the equations it does not matter whether degrees or radians are used. 3.1. Declination Angle The declination angle is described in figure 1.5 and 1.6. The equation used to calculate the declination angle in radians on any given day is: 284 + n / = 23.45 sin2 (3.1) 180 365.25 where: / GHFOLQDWLRQDQJOH UDGV n = the day number, such that n = 1 on the 1st January. Figure 3.1: The variation in the declination angle throughout the year. The declination angle is the same for the whole globe on any given day. Figure 3.1 shows the change in the declination angle throughout a year. Because the period of the Earth's complete revolution around the Sun does not coincide exactly with the calendar year the declination varies slightly on the same day from year to year. 3.2. The Hour Angle The hour angle is described in figure 1.6 and it is positive during the morning, reduces to zero at solar noon and becomes increasingly negative as the afternoon progresses. Two equations can be used to calculate the hour angle when various angles are knoZQ QRWHWKDW/FKDQJHVIURPGD\WR GD\DQG.DQG$FKDQJHZLWKWLPHWKURXJKRXWWKHGD\ . cos sin A Z sin & = − (3.2) cos/ sin . − sin /sin & sin & = (3.3) cos/cos& where: & WKHKRXUDQJOH . WKHDOWLWXGHDQJOH AZ= the solar azimuth angle; / WKHGHFOLQDWLRQDQJOH & = observer's latitude. Note that at solar noon the hour angle equals zero and since the hour angle changes at 15° per hour it is a simple matter to calculate the hour angle at any time of day. -
Using the SFA Star Charts and Understanding the Equatorial Coordinate System
Using the SFA Star Charts and Understanding the Equatorial Coordinate System SFA Star Charts created by Dan Bruton of Stephen F. Austin State University Notes written by Don Carona of Texas A&M University Last Updated: August 17, 2020 The SFA Star Charts are four separate charts. Chart 1 is for the north celestial region and chart 4 is for the south celestial region. These notes refer to the equatorial charts, which are charts 2 & 3 combined to form one long chart. The star charts are based on the Equatorial Coordinate System, which consists of right ascension (RA), declination (DEC) and hour angle (HA). From the northern hemisphere, the equatorial charts can be used when facing south, east or west. At the bottom of the chart, you’ll notice a series of twenty-four numbers followed by the letter “h”, representing “hours”. These hour marks are right ascension (RA), which is the equivalent of celestial longitude. The same point on the 360 degree celestial sphere passes overhead every 24 hours, making each hour of right ascension equal to 1/24th of a circle, or 15 degrees. Each degree of sky, therefore, moves past a stationary point in four minutes. Each hour of right ascension moves past a stationary point in one hour. Every tick mark between the hour marks on the equatorial charts is equal to 5 minutes. Right ascension is noted in ( h ) hours, ( m ) minutes, and ( s ) seconds. The bright star, Antares, in the constellation Scorpius. is located at RA 16h 29m 30s. At the left and right edges of the chart, you will find numbers marked in degrees (°) and being either positive (+) or negative(-). -
NOAA Technical Memorandum ERL ARL-94
NOAA Technical Memorandum ERL ARL-94 THE NOAA SOLAR EPHEMERIS PROGRAM Albion D. Taylor Air Resources Laboratories Silver Spring, Maryland January 1981 NOAA 'Technical Memorandum ERL ARL-94 THE NOAA SOLAR EPHEMERlS PROGRAM Albion D. Taylor Air Resources Laboratories Silver Spring, Maryland January 1981 NOTICE The Environmental Research Laboratories do not approve, recommend, or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to the Environmental Research Laboratories or to this publication furnished by the Environmental Research Laboratories in any advertising or sales promotion which would indicate or imply that the Environmental Research Laboratories approve, recommend, or endorse any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this Environmental Research Laboratories publication. Abstract A system of FORTRAN language computer programs is presented which have the ability to locate the sun at arbitrary times. On demand, the programs will return the distance and direction to the sun, either as seen by an observer at an arbitrary location on the Earth, or in a stan- dard astronomic coordinate system. For one century before or after the year 1960, the program is expected to have an accuracy of 30 seconds 5 of arc (2 seconds of time) in angular position, and 7 10 A.U. in distance. A non-standard algorithm is used which minimizes the number of trigonometric evaluations involved in the computations. 1 The NOAA Solar Ephemeris Program Albion D. Taylor National Oceanic and Atmospheric Administration Air Resources Laboratories Silver Spring, MD January 1981 Contents 1 Introduction 3 2 Use of the Solar Ephemeris Subroutines 3 3 Astronomical Terminology and Coordinate Systems 5 4 Computation Methods for the NOAA Solar Ephemeris 11 5 References 16 A Program Listings 17 A.1 SOLEFM . -
Coordination for Sun Location When Planning a PV System, It Is Crucial To
Coordination for Sun location When planning a PV system, it is crucial to know at any given time the position of the Sun in the sky as seen from the location of the solar system. In today's lecture we will introduce two coordinates systems that we will use to locate the sun in the sky. First the geographic and then the celestial coordinate systems. There are several web applications that you can use for finding the path of the sun. For example, these pictures are obtained from Wolfram Alpha and you can see the zenith view of the observer during the solstice of winter and summer in Delft, which represents the lowest and the highest path drawn by the sun during the year. Indeed, the maximum altitude of the sun which will be introduced in the next slides increases from almost 15 degrees to 61 and so also the daylight the duration becomes more than the double. Note that the sun apex during the day will have very important implication in case the PV system is embedded in a landscape with obstacles. As we shall see in the following lecture, finding the position of the Sun above a solar panel situated on the earth is not a trivial trigonometric problem. Before breaking the procedure in small steps in order to solve such problem, let's learn some important terms. To begin we shall consider a panel as a surface tangent to the earth crust so it is just lying on the surface. Later on we will tilt it in order to optimize its yield. -
Astrocalc4r: Software to Calculate Solar Zenith Angle
Northeast Fisheries Science Center Reference Document 11-14 AstroCalc4R: Software to Calculate Solar Zenith Angle; Time at sunrise, Local Noon, and Sunset; and Photosynthetically Available Radiation Based on Date, Time, and Location by Larry Jacobson, Alan Seaver, and Jiashen Tang August 2011 Recent Issues in This Series 10-15 Bluefish 2010 Stock Assessment Update, by GR Shepherd and J Nieland. July 2010. 10-16 Stock Assessment of Scup for 2010, by M Terceiro. July 2010. 10-17 50th Northeast Regional Stock Assessment Workshop (50th SAW) Assessment Report, by Northeast Fisheries Science Center. August 2010. 10-18 An Updated Spatial Pattern Analysis for the Gulf of Maine-Georges Bank Atlantic Herring Complex During 1963-2009, by JJ Deroba. August 2010. 10-19 International Workshop on Bioextractive Technologies for Nutrient Remediation Summary Report, by JM Rose, M Tedesco, GH Wikfors, C Yarish. August 2010. 10-20 Northeast Fisheries Science Center publications, reports, abstracts, and web documents for calendar year 2009, by A Toran. September 2010. 10-21 12th Flatfish Biology Conference 2010 Program and Abstracts, by Conference Steering Committee. October 2010. 10-22 Update on Harbor Porpoise Take Reduction Plan Monitoring Initiatives: Compliance and Consequential Bycatch Rates from June 2008 through May 2009, by CD Orphanides. November 2010. 11-01 51st Northeast Regional Stock Assessment Workshop (51st SAW): Assessment Summary Report, by Northeast Fisheries Science Center. January 2011. 11-02 51st Northeast Regional Stock Assessment Workshop (51st SAW): Assessment Report, by Northeast Fisheries Science Center. March 2011. 11-03 Preliminary Summer 2010 Regional Abundance Estimate of Loggerhead Turtles (Caretta caretta) in Northwestern Atlantic Ocean Continental Shelf Waters, by the Northeast Fisheries Science Center and the Southeast Fisheries Science Center. -
Solar Hour Angle ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved
ECE 333 – GREEN ELECTRIC ENERGY 12. The Solar Energy Resource George Gross Department of Electrical and Computer Engineering University of Illinois at Urbana–Champaign ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved. 1 SOLAR ENERGY Solar energy is the most abundant renewable energy source and is considered to be very clean Solar energy is harnessed for many applications, including electricity generation, lighting and steam and hot water production ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved. 2 Page 1 SOLAR RESOURCE LECTURE The solar energy source Extraterrestrial solar irradiation Analysis of solar position in the sky and its application to the determination of optimal tilt angle design for a solar panel sun path diagram for shading analysis solar time and civil time relationship ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved. 3 UNDERLYING BASIS: THE SUN IS A LIMITLESS ENERGY SOURCE .files.wordpress.com/2012/11 johnosullivan Source : http://Source ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved. 4 Page 2 SOLAR ENERGY The thermonuclear reactions, as the hydrogen atoms fuse together to form helium in the sun, are the source of solar energy In every second, roughly 4 billion kg of mass are converted into energy, as described by Einstein’s famous mass–energy equation This immense energy generated is huge so as to keep the sun at very high temperatures at all times ECE 333 © 2002 – 2018 George Gross, University of Illinois at Urbana-Champaign, All Rights Reserved.