Homework Question Set 6 -- Due Nov 6


Here is a table which gives the coordinates of a random sample of globular clusters. The table gives the astronomer's name for the cluster, its right ascension (in hours and minutes), its declination (in degrees and minutes), and its distance (in kiloparcsecs). A quick glance reveals that the clusters are all over the sky, but they're not evenly distributed over the sky.
Name   R.A. Declination Dist (kpc) Name   R.A. Declination Dist (kpc)
47 Tuc 00 h 22 m -72 deg 21' 4.6 M 92 17 h 16 m +43 deg 12' 7.8
NGC 362 01 h 02 m -71 deg 07' 9.0 NGC 6352 17 h 22 m -48 deg 26' 5.4
Pal 2 04 h 46 m +31 deg 23' 35.0 NGC 6362 17 h 27 m  -67 deg 01 7.1
NGC 1851 05 h 12 m -40 deg 05' 10.8 M 14 17 h 35 m -03 deg 15' 10.2
NGC 2802 09 h 11 m -64 deg 39' 9.2 NGC 6440 17 h 46 m -20 deg 21' 3.7
NGC 3201 10 h 17 m -46 deg 09' 5.0 NGC 6496 17 h 56 m -44 deg 13' 9.0
NGC 4372 12 h 23 m -72 deg 24' 4.9 NGC 6528 18 h 02 m -30 deg 04' 7.3
Omega Cen 13 h 24 m -47 deg 03' 5.2 NGC 6553 18 h 06 m -25 deg 56' 5.9
M 5 15 h 16 m +02 deg 16' 7.6 NGC 6624 18 h 21 m -30 deg 23' 8.5
M 80 16 h 14 m -22 deg 52' 8.3 NGC 6642 18 h 28 m -23 deg 30' 6.2
M 4 16 h 21 m -26 deg 24' 2.1 NGC 6712 18 h 50 m -08 deg 47' 7.6
M 107 16 h 30 m -12 deg 57' 5.9 NGC 6752 19 h 06 m -60 deg 04' 4.2
M 13 16 h 40 m +36 deg 33' 7.2 M 55 19 h 37 m -31 deg 03' 5.2
M 10 16 h 54 m -04 deg 02' 4.4 M 15 21 h 28 m +11 deg 57' 9.4
M 19 16 h 59 m -26 deg 11' 10.6 M 30 21 h 38 m -23 deg 25' 8.2

1) The diagram below represents a pole-on view of Earth from outside the Milky Way Galaxy. Earth is at the center, the lines show the various directions of right ascension, and each circle represents a distance of 1 kiloparsec from the Earth. Plot the right ascensions versus the distance of each globular cluster in the list. What is the approximate right ascension of the Galactic Center?
3 hours         6 hours         9 hours         12 hours         15 hours         18 hours         21 hours        


2) Below is another diagram which takes a view from above the equator. Again, Earth is at the center, and each circle represents a distance of 1 kiloparsec, but this time, the directions are degrees of declination. Plot the globular cluster declinations against their distance. What is the declination of the Galactic center?
+90 degrees         +60 degrees         +30 degrees         0 degrees         -30 degrees         -60 degrees         -90 degrees        


3) According to the data given above, what is the approximate distance to the Galactic Center?
1 kpc         3 kpc         5 kpc         7 kpc         9 kpc        


4) In the direction of what constellation does the Galactic center lie?
Pegasus     Cetus     Orion     Sagittarius   Cancer     Leo     Virgo     Libra     Capricorn     Hercules     Aquila    


5) Is the Galactic Center best viewed from the Northern or Southern hemisphere of the Earth?
Northern hemisphere     Southern hemisphere     Both hemispheres can see the Galactic center equally well.