Well done. Iris is a good choice. Maybe try taking a time series of a known variable star to give you a data set as a test. A good test is a SXPHE type star. They have a fast variation over about an hour.
A list of them is here
http://www.aavso.org/vsx/index.php?view=results.submit2
A good example in the evening sky now would be V0462 Hya or KZ Hya