CC Comae Berenices - 2019-03-28

[coatesg]

CC Com is a W UMa type eclipsing variable - these are low mass contact binaries that overflow their Roche lobes. I captured this light curve last night (28th Mar 2019). Each point is a single 40sec exposure through an Astrodon V filter, on my 350mm f4.6 Newt (using ST2000XM). Primary minimum (the second) has an interesting flat spot in my data - from other curves in the AAVSO database, this looks to be correct.

The variable apparently (recently) shows some variation in the timings of the minima vs the original calculated timings - here's the graph from the Krakow database going back over time. I need to read up on how to correctly determine the minimum, and then do the conversion back to HJD to compare this to my readings. 

[coatesg]

(Did also find V1117 Her at a minimum at around mag 14.8 compared to it's usual 12-13 at maximum)

[Dave Smith]

Lovely set of data. This one brings back memories. Many Moons ago I did the Open University practical course "Observing the Universe" in Majorca and this star we used as a team project introducing us to photometry using MaximDL on one of the nights.

Dave