This weeks light curve is of the star CRTS J032905.5+305924. It is a member of the NGC1333 star forming region, according to the parallax from Gaia, which places it at a distance of 307pc. This target region is one of the two fields in Perseus, which are now starting to be visible in the morning again. Hence, the first of the Winter targets are now available to have a first look after their tour behind the Sun.

The light curve (we do show the V, R, and I-Band measurements) looks very unremarkable. It shows only a very small scatter, that might be explainable with the normal noise in the measurements. However, there are three data points (one in each filter) that show the object dimmer at JD=2458019. These are not measurement errors, but show a real dimming. The object is actually a known eclipsing binary with a period of 17.2421 days.

Our data shows, how hard it is to find eclipsing binaries with such long, or even longer periods. Despite the fact that we have about 100 data points per filter over the last 4.5 years, we have detected the eclipse only once. In the entire observing period there have been about 100 eclipses. However, given the period is more or less a quarter day plus 17 days, and we typically observe the target an integer number of days apart, realistically we would probably only be able to detect every 4th eclipse. This leaves only 25 to be detectable for us. This is one in 70 days for our observing period. So it is not surprising to have only one detection with 100 observations.