ASTRONOMY 322 Winter Quarter 2005     Name ________________________

1. Give the following info for Seattle on December 21:
 
a) Sidereal time at midnight (to nearest half hour): ______

b) Highest altitude of celestial equator:  ________

c) Highest altitude of ecliptic:  ________

d) RA and Dec of Sun: ______   ______

e) Altitude and Azimuth of sun at noon: ______  ______

f) Altitude of Polaris: _______

g) Highest altitude reached by Sirius (RA=7hr, Dec =-17deg): ______


2. Arcturus is a bright star near the Big Dipper (arc to Arcturus from
the handle). Its visual mag is -0.04 and its blue mag is 1.19. It's RA
is 14h15m and its Dec is +19deg11' (epoch 2000). Its parallax is 0.09
arcsec and its proper motion is 2.2 arcsec/yr. The BC is -0.8. Its
temperature is about 4100K.

a) Which hours will it be visible from Seattle tonight (assuming its 
clear, darkness is from 6pm to 7am and you can see stars in the sky
4 hrs east and west of the meridian)? from ______  to ______


b) What time will it reach its highest altitude? ______


c) What is the distance to Arcturus in pc? _____


d) What is its absolute visual mag? ____


e) What is its absolute bolometric mag?  _____


f) What is its luminosity? ___________ ergs/s



g) At what wavelength does it emit its maximum energy? ________Angstroms



h) What is its radius (in cm and solar radii)? _______cm   _________ Rsun



i) What is its tangential velocity? ________ km/s



j) From all the above, estimate its spectral and luminosity class. ________








3. The 10m Keck telescope is the largest ground-based optical telescope,
the APO 3.5m is the largest telescope UW which UW partly owns and the 2.4m
Hubble Space Telescope is the largest telescope in space.

a) QUANTITATIVELY compare the light gathering power and resolution
of the 3 telescopes (i.e. give numbers, don't just say one is bigger
than another but express as a number ratio Keck:APO:Hubble). For resolution, 
take into account both theoretical and
practical resolution, knowing Keck is on Mauna Kea at 14,000 ft and
APO is at 9000ft.

LGP:






Resolution:






b) If they had the same focal lengths, compare how much fainter Keck
could image a point source in a 1 hr integration with a CCD than could
APO and Hubble (ignore the resolution differences).

Keck can go ______mags fainter than APO and ______mags fainter than HST.





c) Give an example of the best kind of project that would take 
advantage of the unique aspects and the access to each telescope (remember
that APO is run remotely from UW).

Keck:




APO:




HST:


















4. Classify the 5 spectra on the following page and give your reason
for the classification in each case.

a)



b)



c)



d)



e)



f)



5. An eclipsing binary has an orbital period of 2.92days, a total eclipse
length of 18 hrs and totality lasts 4h, while the spectra indicate a relative
orbital speed of 200 km/s.

a) What are the relative radii of the two stars? R1/R2 = ________



b) What are the actual stellar diameters in km? D1 _______km  D2  __________km