sky subtraction

This guide will take you through the steps you need to do basic photometry. Photometry is useful for projects where you need to measure the amount of light coming from a star or other celestial object. These projects include open clusters, supernovae, planet transits and many others. You can do this with sample data available from the public archive, or with data from your own observations if you have an account. After doing this activity you should be able to:

* Use SalsaJ to measure the brightness of stars in an image