Download presentation
Presentation is loading. Please wait.
Published byGeorge Watts Modified over 9 years ago
1
Today! From Earth’s Perspective: Celestial Motion: Stellar Motion Solar Motion Planetary Motion
2
Some stars and constellations Are circumpolar—never rise or set.
3
Constellation vs Asterism!
4
A constellation is one of 88 listed ‘states’ or regions in the sky: like Orion.
5
An asterism is not on the list Of 88, but forms a shape In the sky: like the Big Dipper, Part of the constellation Ursa Major.
6
Once you find the North Star, Turn around 180 degrees— The Ecliptic and the planets will be in the sky toward the South. Finding Planets :
7
Circumpolar Constellations at our Latitude.
8
The stars (at a given time of night) shift 1 degree a day Because the earth is orbiting the sun. Thus the sidereal day is 23 hours and 56 minutes: It is the time for a star to return to the same place In the sky.
9
seasons caused by tilt of earth’s axis, solstices--maximum and minimum light, equinoxes equal light on northern and southern hemisphere.
11
Solar motion: Mean solar day--24 hours by definition. Average return of sun to same angle relative to the horizon.
12
NOTES: Planetary motion: retrograde motion-retrograde motion--apparent backtracking of planets in sky from earth's perspective. inner planets--Me and Ve --stay within 'maximum elongation'. conjunction vs opposition
13
Mars going RETROGRADE: journeying backward against constellations.
14
Venus: always within 46 degrees of the sun— its MAXIMUM ELONGATION (Mercury within 26 degrees)
15
Mercury 8/30/02 Above Cloud Center w/ Venus Upper Left
16
Note conjunction and opposition as seen from the Earth.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.