Calculate distance between stars in a globular cluster?

[caesarborgia2]

Would it be possible to calculate the approximate distance between stars in a globular cluster by doing something simple like this:

Approximate distance to a cluster: 25,000 Ly
Two stars in the cluster just barely resolved in my telescope (resolution about 1 arcsec)

Therefore: 2pi (25,000)/60*60*360

equals approximately 0.12Ly, or about 0.037pc?

Thanks.

 

[Chronos]

that is pretty much how its done. scientists try to find variable stars wth fairly well known properties [standard candles] and muddle their way from there.