Lab 3 GOOD

Motion of the Sun Student name: Alana Firman Goal : To study the motion of the Sun and to learn about the zodiacal constellations. The Ecliptic The Sun has two different apparent motions through the sky. Once each day it rises in the eastern part of the sky, crosses the observer’s local Celestial Meridian at midday, then sets in the western part. The average time between two consecutive meridian crossings (transits) of the Sun is defined to be 24 hours and 0 minutes, or one mean solar day. The exact points where the Sun rises and sets vary with the seasons. We’ll study that effect in another project. The Sun’s other apparent motion is slower. The Earth orbits the sun every 365.256 days. As viewed from the Sun, this motion carries Earth eastward relative to the background stars (in the sky, east is the direction of increasing right ascension). From our point of view, the Sun appears to circle the Earth, also moving eastward relative to the background stars. The path of the Sun’s apparent motion on the celestial sphere is called the ecliptic . Since once around the ecliptic equals 360°, the Sun appears to move slightly less than 1° per day (or almost 180° per half year). Thus, stars that happen to be next to the sun in the daytime sky in December, and therefore cannot be seen will be visible at night in June, when the Sun is in the opposite part of the sky! This apparent motion of the Sun relative to the stars also means that stars rise about 4 minutes earlier each night. The ecliptic is divided into 12 constellations called the zodiacal constellations. The Sun passes though these constellations at the approximate rate of one per month, so they are convenient for roughly describing the sun’s location on the celestial sphere. According to astrologers, the position of the Sun and planets among the zodiacal constellations at the time of your birth determined your future. Tracking the sun We want to watch the sun’s motion around the ecliptic over a period of one year. To get started execute the following  Click on the GROUND icon in the horizontal menu  Set the date to the 1 st day of this semester second month and the time to 22 pm  Click on the search icon in the vertical menu and type in the Sun  Center the sun using the CENTER icon on the horizontal menu bar  Click on the constellation line and labels  Record the required information in result 1 in the table below

 Now increase the time speed by clicking on the fast forward icon in the horizontal menu bar a couple of times until you get to the next month and record the information until you are done with the whole year. Result 1: The Sun’s motion Date Constellation Name Right Ascension Declination Hours of Daylight Planets Near Sun 2/1/24 Capricorn 21h01m25.75s -16 degrees 56’36.3” 17h 16m Saturn, mercury, venus 3/1/24 Aquarius 22h54m14.63s -6 degrees 59’57.8” 17h 42m Saturn 4/1/24 Pisces 0h47m44.60s +5 degrees 7’20.s” 19h06m Venus, Mercury 5/1/24 Aries 2h39m9.49s +15 degrees 31’51.6” 19h39m Jupiter, Venus 6/1/24 Taurus 4h42m48.87s +22 degrees15’5.8” 19h51m Jupiter, Mercury, Venus 7/1/34 Gemini 6h47m11.18s +22 degrees 44’9.4” 20h00m Venus, Mercury 8/1/24 Cancer 8h51m33.19s +17 degrees 37’13.0” 19h45m Venus 9/1/24 Leo 10h47m6.88s +7 degrees 43’6” 19h10m Mercury 10/1/24 Virgo 12h35m46.33s -3 degrees 46’46.1” 18h29m Mercury 11/1/24 Libra 14h31m12.58s -14 degrees 54’40.4” 17h52m Mercury 12/1/24 Oph 16h35m57.98s -22 degrees 2’05.0” 16h37m Mercury 1/1/24 Sagittarius 18h49m23.70s -22 degrees 57’11.5” 16h48m Mars  In which general direction on the celestial sphere (N, S, E, W) does the Sun move relative to the stars? The sun moves closer and away from North (N).  About how many days does it take for the Sun to make one trip around the ecliptic? 25 days.