Here are a few CV target suggestions you might consider:
EI UMa - Intermediate Polar. Not much coverage so far this year. Runs as long as possible are most helpful. This is one of several IP’s that are known to flare. It’s running around 15m right now.
V667 Pup - Another IP with limited coverage so far this season. It is running between 14 and 14.5m.
V418 Gem - Evening object and in the latter part of its observing season so time series are particularly valuable to give a long baseline for this year’s data. 17th magnitude but with an 8 minute white dwarf spin rate, 2 minute exposures are not too long.
Walt and others - I’m curious if the spin period is evident in the AAVSO data on EI UMa, and if so, in what filters. If I remember correctly, the spin modulation in this IP was very blue (maybe only in U band at times?).
Hi Koji. I don’t know if we are able to see the white dwarf spin rate in our data. As you say, it is difficult in optical. Richard Sabo has been doing a bunch of IP white dwarf spin analysis for a paper that several of us are working on. He is better at that analysis than I am. I’ll ask him to take a look.
Just one person has submitted a time series on any of these three objects since I had posted this. (Thanks Ken Menzies for your EI UMa data!) I take that to mean many people have systems they are working on and are continuing those. I know that is the case for many. Great. It’s ideal if people have work they are already doing and not in need of suggested targets. Other thoughts though? What can I do to help observers?
Richard Sabo is on vacation so I did an analysis of the nine most recent sets of EI UMa data submitted to the AAVSO and get the periodogram below. The two highest power peaks are at periods of 0.008894 and 0.008974 days. The stronger of those two is close to the sideband period of 0.008978 that you note on your IP catalog webpage. I don’t see any clear evidence in this analysis of the actual WD spin period of 0.00858 days.
I realized later last night I had forgotten to convert the JD times for the data to HJD. I did that this evening and also included the new data submitted by Graham Darlington and now have the following periodogram. Still no indication of the direct white dwarf spin signal. One of the two peaks I reported last night around the reported sideband frequency has weakened and the strongest signal is the peak at 0.008973d. That’s 775.3s vs the reported sideband of 769.63s.
Here’s a further update. I spent some time learning how to use Peranso and have analyzed all the data submitted since October 24, 2025. The strongest signal in the graph below is at a period of 0.0089079 +/- 0.0000001 days which is statistically the same as the sideband signal reported to be 0.0089078 days. In units of seconds, this analysis finds the sideband signal to be 769.64s vs. the reported 769.63s. I still don’t see any clear evidence of the actual white dwarf spin period of 0.00858d = 741.6s unfortunately.
Thank you to the observers who have been working this star!
