fitting a line, associating stars

I spent a long time on the phone with Lang today discussing various matters but in particular our objective function for matching stars between an image and a catalog. This objective function is necessary to write down in advance of us declaring success (or anything else) in our plan to nail tweak next week. (Tweak is the part of Astrometry.net that measures detailed focal-plane distortions.)

I also dusted off our document about fitting a straight line to data. Part of my reminiscing about Roweis has brought me back to this subject and I promised myself I would finish that up. It could be a useful document and I learned that it is very close. I started to mark up what we have.