Things are moving pretty slowly now. I've put together HR diagrams from the 2MASS data now, but they're very sketchy. The turnoff point is fairly clearly defined, but the main sequence continues on past it which is confusing. The red giant branch is also pretty wide which makes things harder. I'm also supposed to be finding the red giant clump, but it's not sticking out at all.
I did end up going through the list of all the stars and pull out about 20 that are good candidates for variable stars and have sent those on to Dr. Twarog to take a closer look at. Seven or eight of them probably had large errors due to being close to the edge of the frame where the CCD sensitivity isn't always consistent. But aside from that, there's a good possibility that we'll be adding to the number of known variable stars in NGC 7142 (currently 1).