The early twiflats are probably worthless.

Source SPT-CL2135-5726 has the wrong name in the FITS header.

The early data of SDS2034+0001 is a focus curve; the later data 
should be useful for photometric standards.  Focus curve was
found to have changed by 9 mm compared to April, possibly as a result
of installing an ADC on Clay.

Seeing was not the best --- mostly around 1 arcsec, sometimes worse.

Some of the SDSS0432 files are bad --- contrails, loss of tracking