1. 10 full moons fit within 5 degrees (the moon is 0.5 degree across). Since the sun and moon have the same angular size (remember a total eclipse of the sun --- they are the same size !) 10 suns would also fit across 5 degrees.
2. Number of arcsec in 360 degrees is 360 x 60 x 60 = 1,296,000 (quite a lot !). Recall there are 60 arcmins in 1 degree and 60 arcsecs in one arcmin.
3. 10 degrees. Try to remember the "handy angles" : finger=1 degree; three fingers=5 degrees; fist=10 degrees; index-pinky=15 degrees; outstreached hand=20 degrees.
4. False. The dipper is an ASTERISM --- only a part of the constellation of Ursa Major
5. Canis Major; Ursa Minor; Auriga. You should know these by now from the labs.
6. First magnitude star is brightest (recall, smaller magnitude numbers are brighter).
7. Difference is 10 magnitudes. Recall that 5 magnitudes is a factor of 100 in brightness. So 10000=100x100 is 5+5=10 magnitudes different.
8. False. Gamma rays are at the shortest wavelength end of the EM spectrum. Recall the sequence : Radio, Microwave, infra-red, optical, untra-violet, x-rays, gamma rays.
9. X-ray; Gamma-ray; Ultra-violet; Far infra-red.
10. nano means 10-9 or one billionth. Recall : micro=10-6 milli=10-3; kilo=103; mega=106; giga=109.
11. I cant do sketches on the web easily : look at figure c in appendix C on page 122 of the manual. The important parts are : the thin corrector lens; the primary concave mirror (with a hole in it); the secondary convex mirror up in the center of the corrector lens; the eyepiece behind the primary.
12. The longer the focal length of the eyepiece the SMALLER the magnification and the LARGER the field of view.
13. A 4 meter mirror at f/8 has an effective focal length of 4x8=32 meters. (Recall, f-ratio is the ratio of the focal length of the element to its diameter). To get a magnification of x100 we need an eyepiece with a focal length of 1/100 x 32 meters = 0.32 meters = 32 centimeters. (Recall, magnification is the focal length of the primary divided by the focal length of the eyepiece).
14. 16 inch telescope has 4 times the collecting area of a 8 inch telescope (16/8 = 2 squared). The faintest stars can therefore be 4 times fainter. This corresponds to a difference in magnitudes of 2.5xLog(4) = 1.5 magnitudes. So the limiting magnitude is 14 + 1.5 = 15.5.
15. False. The zodiac constellations are grouped around the ECLIPTIC, not the equator.
16. False. The point overhead is the zenith. (The NCP is only overhead for an observer standing at the north geographic pole).
17. Meridian : great circle passing through the NCP and the zenith, it cuts the horizon due north and due south. Zenith: the point directly overhead. Horizon Plane : the tangent plane to the earth at the observer's location. Transit : the moment when an object crosses the meridian (moves from the eastern hemisphere into the western hemisphere; Synodic vs Sidereal : the synodic period is the period between two consecutive similar phases or positions of a planet or sun in the sky. The sidereal period is the time between two consecutive alignments with the same star --- it is the true orbit or rotation period.
18. The altitude of a transiting object (SALT) = 90-Lat+Dec. So we want this to equal 90 (directly overhead). so 90-Lat+Dec=90, so Lat=Dec. Now the Dec of the mid-summer sun is +23.5 so the latitude in question is +23.5. This is also called the Tropic of Cancer.
19. 11 pm EST (Use your star wheels to do this).
20. Cassiopeia is circumpolar in Charlottesville. It is the only one sufficiently far north to be within 38 degrees of the NCP so that it never sets.
21. The Equator. At latitude zero, the circumpolar zones have NO size, and so there is no region of the celestial sphere that is permanently below the horizon.
22. On March 21 the sun is at the vernal equinox, moving from the southern celestial hemisphere into the northern celestial hemisphere.
23. Dec of the sun is largest on June 21, the summer solstice, when it has a value of +23.5 degrees.
24. a) Altitude of NCP is 38 degrees (ie the latitude). b) altitude of the celestial equator is 52 degrees (ie 90-lat). c) 14 degrees because the altitude on the meridian is 90-Lat+dec = 90-38+(-38) = 14.