Phys 102 Astronomy Name ____________________Key POSITIONS OF THE PLANETS PLANETARY POSITIONS WITH RESPECT TO THE SUN: Use appendix 11 in the Field Guide for February 15, 2006 to complete the following table: Planetary Atlas Object Elongation Constellation Longitude Chart # Sol () 327° 0° 32 Cap/Aqr boundary Mercury (☿) 341° 341°-327°=14° E 32 Aquarius Venus(♀) 289° 327°-289°=38° W 42 Sagittarius Mars (♂) 59° (360°+59°)-327°=92° E 10/23 Taurus Jupiter (♃) 228° 327°-228°=98° E 28/40 Libra Saturn (♄) 126° (360°+126°)-327°=159° E 13/25 Cancer PLANETARY POSITIONS IN THE SKY The digram below shows an observer looking south at sunset. From the planetary longitude of the sun and planets abovee, show where the planets will be in the observer’s sky (some may be below the horizon). Discuss how these positions correspond to the times the planets will be visible to this observer (eg. after sunset, before sunrise or most of the night). Sun’s PL + 90° _______57° m Observer’s meridian Come look t for the planets y with me! Sun’s PL ± 180° Sun’s PL _______147° E observer Sun setting on W _______327° looking western horizon south v j Sun’s PL - 90°: _______237° Planets in the Sky Solution.doc 2/13/2006 PLANETARY POSITIONS IN THE SOLAR SYSTEM A view of the solar system as seen FROM ABOVE THE NORTH ECLIPTIC POLE with the sun in the center is shown below. The line from the Earth ( ) to the sun () represents the planetary longitude of the sun. For each of the five visible planets, 1) Center a protractor on the Earth, measure the elongation angle from the sun's longitude. 2) Use a ruler to determine where this crosses the orbit of the planet you're plotting, and mark the planet's position on its orbit. Special Note: Can you be certain where Mercury and Venus are in their orbits? How many positions for each planet are possible? What information will help you figure this out? 3) Describe the planetary configuration position of each planet. Sol’s Planetary Longitude: __________ 327° Eastern Elongation Western Elongation Venus: Mercury: 327°-289° 341°-327° = 38° W = 14° E Saturn: (360+126)°-327° = 159° E Mars (360+59)°-327° Jupiter: = 92° E 327°-228° = 98° W y v m j Center protractor t on Earth! .