Question

2. Distances of Globular Clusters. (a) If we assume that a globular cluster 5 minutes of arc in diameter is actually 25 pc in diameter, how far away is it? Hint: Use the small angle formula from the previous homework.

(b) Suppose this globular cluster is in the direction of the galactic bulge (note that this is different from saying it’s in the direction of the galactic center). Sketch an edge-on view of the galaxy and use the sun’s position in the galaxy to indicate the approximate position of this globular cluster.

Answer 1

2. (a) Small-angle formula is given by:

where the angular diameter is in seconds of arc.