It's time for a new set of transformation coefficients. I've been looking at the Landholt equatorial fields in VSX <http://www.aavso.org/standard-stars-vsp> which have photometry available to VPHOT. As my fov is rather small (~20 arcmin), many of these fields have only a few usable stars. I'm wondering how effective it would be to combine the photometry of several such fields into one analysis batch? Arne has recommended doing the transformations on different fields and averaging the results. Wouldn't combining the photometry from the different fields give the same (or similar) result?
If I can get some clear skies, I'll give it a try and report back but I would like to hear any caveats while I'm waiting for those rare skies.
Jim Roe [ROE]