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This 10 page Class Notes was uploaded by Ashlee Heaney on Wednesday September 30, 2015. The Class Notes belongs to ASTR 104 at Western Kentucky University taught by Staff in Fall. Since its upload, it has received 16 views. For similar materials see /class/216701/astr-104-western-kentucky-university in Astronomy at Western Kentucky University.
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Date Created: 09/30/15
Average Declination of the Sun Date 01 Jan 02 Jan Declination Date Declination e ecllnatlon Date DecllllathII Dat D 22 8 06 Jul 22 7 158 07 Jul 22 6 04 May 161 08 Jul 22 4 05 May 164 09 Jul 22 3 06 May 167 10 Jul 22 2 07 May 169 11 Jul 221 08 May 172 12 Jul 21 9 09 May 175 13 Jul 21 8 10 May 177 14Jul 216 11 May 180 15 Jul 215 12May 182 16 Jul 213 13May 185 17 Jul 21 1 14May 187 18 Jul 210 15May 190 19 Jul 208 16 May 192 20 Jul 20 6 17 May 194 21 Jul 20 4 18 May 196 22 Jul 20 2 19 May 198 23 Jul 20 0 20 May 201 24 Jul 19 8 21 May 203 25 Jul 19 6 22 May 205 26 Jul 19 3 23 May 207 27 Jul 191 24 May 201 28 Jul 18 9 25 May 210 29 Jul 181 26 May 212 30 Jul 18 4 27 May 214 31 Jul 18 O 28 May 215 01 Aug 17 9 29 May 21 02 Aug 171 30 May 211 03 Aug 17 4 31 May 22 O 04 Aug 171 01 Jun 221 05 Aug 16 9 02 Jun 222 06 Aug 16 6 03 Jun 22 4 07 Aug 16 3 04 Jun 22 5 08 Aug 16 0 05 Jun 22 6 09 Aug 15 8 06 Jun 22 10Aug 15 5 07 Jun 228 11 Aug 15 0 08 Jun 229 12Aug 149 09Jun 230 13Aug 146 10Jun 230 14mg 142 11Jun 231 15Aug 131 12 Jun 232 16Aug 136 13 Jun 232 17mg 133 14Jun 233 18Aug 130 15Jun 233 19Aug 127 16Jun 234 20 Aug 123 17Jun 234 21mg 120 18Jun 234 22 Aug 117 19Jun 234 23 Aug 113 20 Jun 234 24 Aug 11 0 21 Jun 234 25 Aug 10 6 22 Jun 234 26 Aug 10 3 23 Jun 23 4 27 Aug 09 9 24 Jun 23 4 28 Aug 09 6 25 Jun 23 4 29 Aug 09 2 26 Jun 23 3 30 Aug 08 9 27 Jun 23 3 31 Aug 08 1 28 Jun 233 01 sep 08 1 29 Jun 232 02 sep 07 8 30 Jun 231 03 sep 07 4 01 Jul 231 04 sep 071 02 Jul 23 O 05 sep 03 Jul 22 9 04 Jul Date Declination Date Declination Notes on Time and Astronomy Measuring Days by the Sun Apparent Solar Time This is also called Sundial Time This is time measured by the actual motion of the Sun across the sky as seen from your location Noon occurs when the sun reaches the local meridian Locations east of you have an apparent time that is later than yours western location have an apparent time that is earlier than yours Since the orbit of the Sun is not a perfect circle the rate of Apparent Solar Time varies through the year Local Mean Solar Time LMT LMT is time based of the motion of a fictional average or mean Sun Using the average motion of the Sun keeps the rate of LMT constant LMT varies from Apparent Solar Time by up to 16 min at certain times of the year The LMT of the Greenwich meridian is called Universal Time UT Standard Time This is time measured by time zones The Earth is divided into 24 zones Each zone is 15 degrees of longitude wide Every clock in the same zone keeps the LMT for the meridian in the middle of the zone The time zone for the western half of Kentucky is the S zone also known as the Central Time Zone The middle of the Central Time Zone is longitude 90 degrees west The Central Time Zone is 6 hours behind UT Daylight Savings Time The idea behind daylight savings time is to advance Standard Time by one hour to give more daylight to the end of the day Areas that use Daylight Savings Time begin using it at 2 am on the first Sunday in April and return to Standard Time at 2 am on the last Sunday in October International Date Line Standard Time advances by one hour per zone as you travel east and goes back one hour for each zone you travel west A traveler could travel far enough to go into yesterday or move into tomorrow To keep this from happening the Earth has an International Date Line Any person crossing it from east to west gains one day Crossing the line from west to east causes you to lose one day Julian days measuring the number of days between any two days can be extremely difficult For this reason the date January 1 4713 BC was designated as Julian day Number 1 Each day since then has been given a consecutive number increasing by one each day Beyond the Day The In many The traditional first day of the week was once Sunday The civil calendar now starts with Monday Lunar Month Also called a Synodic Month It is the time it takes for the Moon to go through a full range of phases A Lunar Month is about 295 days long Some societies arrange calendars to have alternating Lunar Months of 29 and 80 days Many cultures define the Lunar Month to start on the first day a Crescent Moon can be seen Lunar Year Some calendars try to match the Lunar Month with the Solar year by making a year of 12 Lunar Months A year of 12 Lunar Months is only 854 days long The Islamic calendar ignores the difference The Jewish calendar mixes short years with extra long years to keep the calendar more or less matched with the seasons Tropical Year A Tropical Year is the time it takes for the Sun to travel from one Vernal Equinox to the The Gregorian Julian and other Lunar and Solar calendars use a predetermined system of days and weeks adjusted by various intercalary days to keep the calendar in step with the annual motion of the Sun The Gregorian Calendar leap day in February every 4 years is an intercalary day The Names of the Stars Naming stars is an enormous task Even without a telescope the eye can see thousands stars Several ways exist to name stars Traditional Names Many bright stars have names given to them in the past Most of these names are Arabic Vega Capella Betelgeuse and Sadr are examples of traditional Arabic names Fewer than 1000 stars have such names Bayer System One way to name stars is to use a system In the early seventeenth century the astronomer Johann Bayer created such a system He gave the brightest star i each constellation a name consisting of the greek letter at alpha followed by the genitive form the constellation name the genitive form is equivalent to the possessive case in English Other stars receive names in order of brightness going down the greek alphabet The Bayer system gives clues to a stars brightness and location Unfortunately it Greek alphabet only has 24 letters Flamsteed System In the early eighteenth century John Flamsteed devised a new naming system that could name large numbers of stars he gave each star a number start with the westernmost star in each constellation This system could name stars in large numbers Catalog Names Several large catalogs of stars exist These catalogs gives stars numbers The Bonner Durchmusterung gives stars BD numbers Stars with HD numbers come from the Henry Draper Catalogue The Smithsonian Astrophysical Observatory Star catalog uses SAO number while the Hubble Space Telescope Guide Star catalog gives stars HGC numbers All these systems are in use This makes it possible for the same star to have several names The star Dubhe in Ursa Major can also be called Alpha Ursa Majoris and 50 Ursa Major depending on the method used Buying a Star Several organizations exist that will sell the privilege of naming a star for yourself or a friend These organizations provide a certificate and in many cases a map showing the star None of these organizations has any official status with astronomers NASA or the government The Doppler Effect The apparent frequency of a wave is affected by the motion of the source of the wave or the observer If the source and observer are approaching the wave seems to have a higher frequency and shorter wavelength If the source and observer are receding the wave seems to have a lower frequency and longer wavelength Wien s Law As the temperature of a blackbody increases the dominant frequency of it s radiation ml increase also Kirchhoff 3 Laws Law 1 A hot opaque body such as a hot dense gas or a warm solid produces a continuous spectrum a complete rainbow of colors without any spectral lines Law 2 A hot thin gas produces an emission bright line spectrum a series of bright spectral lines against a dark or dim background Law 3 A cool transparent gas in front of a source of a continuous spectrum produces an absorption dark line spectrum a series of dark spectral lines among the colors of the continuous spectrum These dark lines correspond to the locations of the the emission lin the cool gas would produce under the conditions of the second law see above A blackbody is an ideal object that absorbs all frequencies of light completely Fleal blackbodies do not exist But the law basically holds true for all objects Base relescqzemramanan me mm oqacm Lens CumEx H nccmmg ugh Eyepece H AL lt ngmesdunm Vuwswze lt vewaxpmsHEm awgeswzs ass am 2 Haggai 2 mumancAmua mn a Nbs pa mmance Vuwswze a DMmHmmaKem awgessz me Hellele Newlmlzn sum Oqecnva Mum OuncavE 55mm my 3 nccmmg ugh An Eyeuece a 2539s wesdunm andhgm 2 NncmcmancabeHamn 2 Raquuescdhmannn a Easytn akew gggms A Nts peummancem Bust Compound Telescope EyEplcce UDJIBC UVE Mirror lfjuncave 39 r r ff I ifquot 3J0 aq lnwmmgg Light r 4 quot S e m n Clary M 1 HT r H jv39pe rim 1 tr 1 I Advantages Disadvantages WAGON l Less Expensive than refractor No chromatic aberration Easy to make in large sizes Eyepiece in rear Short for the focal length 1 Secondary affects resolution and light 2 Requires collimation 3 large secondary may hinder resolution NOTE Other types of similar reflecting telescopes Schmidt Cassegrain Maksuktov and others mount the secondary mirror in the middle of a corrector plate The plate acts as a lens These telescopes are called Compound Telescopes Other Information 1 01wa Magnification provided by the eyepiece Magnification Focal Length of ObjectiveFocal Length of Eyepiece Magnification dims image and magnifies optical problems Realistic limit about 2 X per mm or 50 X per inch of aperture Telescopes can use invisible radiation radio IR X Ray Gamma etc Radio telescopes are reflecting telescopes Tracking the Sun Plot the position of the Sun for each day you have data Use each graph to find the elevation of the Sun at Local Noon local noon occurs when the Sun has its highest elevation NOT at the clock time 12 noon for each date Name Latitude 900 Local Noon Elevation of the Sun Declination of the Sun ClassDate Date Location Solar Declination Solar Altitude Calculated latitude 7am 8am 9am 10am 11 am Noon 1 pm 2pm 3pm 4pm 5pm Date Location Solar Declination Solar Altitude Calculated latitude 900 800 700 600 Grading Format 5 pt Data and Graph 10 pt Latitude 10 pt 7am 8am 9am 10am 11 am Noon 1 pm 2pm 3pm 4pm 5pm