Lab 3

Motion of the Sun Student name: Ma. Cristina Nicole Mangente 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 1

 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 Constellatio n Name Right Ascension Declination Hours of Daylight Planets Near Sun 01/31/2023 Capricorn 20h58m13.60 s -17°10’01.8” 10h32m Saturn 02/25.2023 Aquarius 22h47m40.42 s -7°39’18.6” 11h26m Saturn 03/31/2023 Pisces 0h40m02.11s +°26’03.2” 12h31m Jupiter 04/30/2023 Aries 2h32m39.16s +14°59’43.1” 13h31m Jupiter 05/31/2023 Taurus 4h35m29.09s +22°00’58.2” 14h15m Mercury 06/30/2023 Gemini 6h39m47.25s +23°07’16.5 14h23m Mercury 07/01/2023 Cancer 8h44m36.20s +18°04’36.2” 13h51m Venus 08/01/2023 Leo 10h40m36.2s +8°22’18.8” 12h54m Venus 09/30/2023 Virgo 12h28m19.05 s -3°0458.3” 12h54m Venus 10/01/2023 Libra 14h24m30.37 s -14°20’20.1” 10h50m Mercury 11/01/2023 Scorpius 16h28m10.73 s -21°42’30.4” 10h05m Mars 12/01/2023 Sagittarius 18h44m47.03 s -23°02’22.5” 9h56m Mars  In which general direction on the celestial sphere (N, S, E, W) does the Sun move relative to the stars? The Sun moves along the eliptic, which is the apparent path of the Sun across the sky over the course of a year.  About how many days does it take for the Sun to make one trip around the ecliptic? It takes the Sun approxiamtey 365.25 days to make one trip around the ecliptic. 2