AAVSO Alert Notice 767 announces an observing campaign beginning immediately on the "propeller" cataclysmic variable CSS_J024048.5+195227 in support of HST observations. Please see the notice for details and observing instructions.
There are threads for this campaign under the following forums:
Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Thanks for your interest in observing J0240. Generally, CCDs have a lower sensitivity in U
than in B. So B is a better filter for getting a good cadence for a time series.
I was planning to get a time series on J0240 tonight using Notre Dame's campus telescope.
I've had good data with unfiltered CCD observations using 20-second exposures and letting that run for hours. The orbital period is 7.5 hours, so you have to be lucky to catch an eclipse of the flaring region. But we predict one will occur during the HST visit. That eclipse will be centered on February 3 at 2:07 UT.
Unfortunately, the clouds are coming in earlier than forecast. They portend a foot of snow for South Bend on Wednesday/Thursday.
I hope you all have better luck with the weather!
Ran in C filter last night (very clear) for 2.5 hours down to 30 degrees. Guessed at 30 sec exposure for my 12.5". SNR was just above 5 by luck!
157 comp had a STD of 0.06 mag. Target had an STD of 0.272 so there was some real variation. Hint at sinusoid with full amplitude of 0.7 mag over 2.5 hr run plus some flickering?? No eclipse.
Data is in AID.
Unfortunately, Wed/Thu will be cloudy! ;-(
The data from last night sounds good. There is a variation on the binary orbital timescale caused by the football shape of the secondary star. Usually the flaring overwhelms that secondary variation.
Just submitted our CV measurements of CSS_J024048.5+195227 from last night and a while ago (Feb 2-3, 2022) to AAVSO Webobs as for our data contribution for this campaign.
Aldrin B. Gabuya
Al Sadeem Astronomy Observatory (OAAA)
Abu Dhabi, UAE