I spent the morning facilitating Moustakas's use of astrometry.net in a science project. He is stacking U-band images into a mosaic. We only needed to adjust two things. (1) We needed to insert a cosmic-ray rejection step into his pipeline. We hacked something together but also thought about how we might insert that into astrometry.net as a standard option. (2) We had to split his multi-extension FITS files into individual images. This is clearly not optimal, but the multi-extension files require a lot of technical infrastructure (tying together the tangent points for multiple arrays on the same focal plane, and fitting or solving multiple images simultaneously) that so far has been off the critical path.