Distance to the Center of the Galaxy

Measuring the Angular Sizes of the Globular Clusters

You will note right away that the apparent angular diameter of these clusters is definitely NOT the same! When you click on each image, you will bring up a new window with a larger view of the cluster. The first thing you must decide when making these measurements is, "What exactly am I supposed to measure?" or, "Where am I suppose to click? The cluster just seems to gradually fade into the star field!" Decide on your criteria for measuring; for example, "just the dark-center part," or "about half-way out to where it seems to end," or "all the way out as far as I can trace stars that appear to be part of the cluster." Just remember, it is going to be harder and harder to see the extent of any given cluster the farther away it is from us.

NGC 6121	NGC 6440	NGC 6496	NGC 6522
NGC 6528	NGC 6544	NGC 6553	NGC 6558
NGC 6569	NGC 6624	NGC 6652	NGC 6656
NGC 6681	NGC 6715	NGC 6723	NGC 6809

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