1. Stars and Constellations Physics 113 Goderya Chapter(s): 2 Learning Outcome:

2. Constellations In ancient times, constellations only referred to the brightest stars that appeared to form groups, representing mythological figures.

3. Finding objects in the sky Constellations Source: Jodrell Bank Observatory

4. Finding objects in the sky Orion Nebula Source: Jodrell Bank Observatory

5. Constellations (2) Today, constellations are well-defined regions on the sky, irrespective of the presence or absence of bright stars in those regions.

6. Apparent view The stars of a constellation only appear to be close to one another Usually, this is only a projection effect. The stars of a constellation may be located at very different distances from us.

7. Star Names Stars are named by a Greek letter (  ) according to their relative brightness within a given constellation + the possessive form of the name of the constellation: Orion Betelgeuze Rigel Betelgeuse =  Orionis Rigel =  Orionis

8. Circumpolar Constellations

9. Non Circumpolar Constellations

10. Constellation of the Zodiac Due to Earth’s revolution around the sun, the sun appears to move through the zodiacal constellations.

11. Constellations from Different Places (SLIDESHOW MODE ONLY)

12. Stellarium http://www.stellarium.org Go download it if you have a computer at home. Its Free http://www.stellarium.org Source: Jodrell Bank Observatory Screen from STELLARIUM (A freeware software)

13. Angles in Astronomy Angles – Circle = 360º =2π radians – Two Perpendicular lines = 90º – 1º = 60 ‘ (arc minutes) – 1‘ = 60 " (arc seconds) – 1 radian = 360x60x60/2π = 206265 " – Sun & Moon Diameter = 0.5º = 30 “ – Extended fist = 5º

14. Angles in Astronomy

15. Small Angle Formula Example for Moon