Measuring absolute brightness is hard. It would be good to compare the measurement error is in brightness of a reference star of about the same magnitude and d

Measuring absolute brightness is hard. It would be good to compare the measurement error is in brightness of a reference star of about the same magnitude and distance(and even perhaps a known variable star) to the observed changes in this star. In the lab under ideal conditions with ideal light sources, it's pretty common for there to be >2.5% error in these types of measurements. For those used to dB unit, this is a ~0.1dB change. In optics, it's very easy to introduce error at this level.