ASTR 106 observation summary, 4 December 2021, DMW

This is a BONUS light curve: it is not a lightcurve of our term-project target and should not be used in the analysis of that target's orbit or size. But to have been there still counts as observation attendance. 

As on our first night, we had thick cloud cover not captured by the forecast: this kept us from observing pre-transit baseline and ingress, and blotted out a few of our frames, notably during egress. But we got good data during the transit and a good post-transit baseline: we can see the depth of the transit and know the time of egress within a few minutes.

We also had pretty high winds, but the direction we were pointing the telescope minimized the effects of this. The temperature was 32 F when we started. There was no moon. The seeing varied around 2.7 arcseconds: worse than normal but not disasterously so.

We took 40 3-minute exposures with no autoguiding: the exposure time was short enough that the stellar images did not streak or broaden significantly due to drifts in telescope pointing. In processing, we rejected first few images due to latent images in the CCD from leaving a bright star on it for too long. We rejected nine more because clouds dimmed the stars by more than a factor of two. A TCS computer crash cost about one exposure's worth of time during egress, but that was while we had some clouds as well; the clouds were more of a problem than the crash. 

Data reduction during the observations by Hernan revealed the transit, but the light curve appeared to be tilted: signal appeared too large at earlier times and too small at later times. As we suggested during the observations, this tilt went away when we calibrated the data properly.