My work – “work”, this is supposed to be amateur astronomy! – in variable star astronomy is mainly observational. I love being out under the sky, estimating variables using the time-tested tools of variabilists that’s been around since, well, Argelander’s days (not really, since I don’t use his step method, but never mind): maps with comp stars printed on paper, a 20 cm Newton reflector and a pair of 15×70 binoculars. Or, not as fun as visual observing but with the added possibility of going a lot fainter, remotely controlled telescopes with the FITS images analysed in Vphot.
So, I am an observational amateur. Statistics and Excel spreadsheets are not my forte, other people are much better at analysing large photometric datasets. For example, my Swedish variabilist colleague, Thomas Karlsson, juggles numbers and comes up with truly amazing results.
Still, I would like to do a bit of analysis. And that’s were VStar enters the picture. It is a great piece of software!
Great software should make the beginning user able to perform central tasks with a minimum of hassle but also have more advanced capabilities available, as the user gets more advanced.
For example, determining a time of maximum for a Mira variable is easily done in VStar; observations are imported from the AAVSO International Database, a polynomial curve is fitted, and the maximum of that function gives the time of max. Other datasets, not in AID, can of course be imported. There are many other powerful features in VStar, for the more advanced user.
Besides its many features and well-designed nature, VStar is free, in active development and cross-platform (which I like, being a Mac user – the world of amateur astronomy software is very Windowscentric). New features being developed or planned for future releases are visible at the project’s SourceForge page.
David Benn, the programmer behind this amazing program, keeps a well-written blog which, among other things, discuss features of VStar such as finding a Mira’s maximum.
If you are, like me, interested in beginning to learn analysing variable star data, a good starting point is VStar.