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I see the dilemma, Max (also shows rage pitfalls CV observers can get into with less than ideal data). If you can confidently and consistently compensate that would be the way to go (sorry!). In any case, it would be important to identify those eclipses where there is some kind of uncertainty in assignment of type.
Yep, I’ll use question mark.
Eclipses No(s): 63, 64, 65 (next day)
State: Quiescence
Profiles: U/N/A, U/N/A, V/N/AAttachments:
Eclipses No(s): 66
State: RisingAnother surprise from CG Draconis – a post-egress hump (PEH) during the very early rising stage of the outburst, combined with high orbital hump amplitude – a U/H/PEH type profile, seen first. There was an interruption in data right after the PEH peak, but we can still see it was rather narrow.
At this state the white dwarf’s accretion disk must still be dim and cold, or at least partially hot, as the bright spot is prominent, peaking at phase 0.85 when it’s directly facing Earth. Its amplitude almost reaches 0.2 mag, making it a “high” hump in my classification.
What normally follows is an asymmetric, slower egress, however, this time we have an opposite case, I think, caused by a PEH. peaking at approximately phase 1.1. This phase coincides with the emergence of the bright spot on the other side of the eclipse. This could signify that the diameter of the bright spot is bigger than the thickness of the accretion disk, or, perhaps, that the disk is unusually optically thin at this early stage of the outburst.
It would be really interesting to have some input on these speculations. Although I have only recorded two eclipses during the rising stage of the CG Dra outburst, I would expect asymmetric egress, with the bright spot concealed by the disk on the other side of the eclipse.
If the disk is so unusually transparent tonight, what suddenly caused it? We have seen no PEHs during previous eclipses after the bright outburst. If the bright spot is unusually large now, extending beyond the accretion disk, which is supported by the absence of the standstill on the egress, then does this signify an increased accretion rate? If so, what has suddenly caused it? We have seen that there was no PEH at all yesterday – the eclipse was asymmetric.
The more data is being collected, the more questions I have.
Max
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Addendum:
I have found a V-shaped counterpart to this U/H/PEH eclipse, observed once at quiescence on May 28. I have called it Sharp-V/H/HA back then – high orbital hump, highly asymmetric. (See attachment, tonight’s U/H/PEH on the left, the Sharp-V one on the right.) Looking at the phase plots, I see both profiles are very similar, so I will rename the May 28 profile to V/H/PEH.
Max
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Eclipses No(s): 67, 68
State: RisingU/N?/A + U/L/S eclipse. Two different profiles on the same night, although there is no clear cut line where eclipse becomes asymmetric in my system. The latter eclipse is still slightly asymmetric.
Max
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Eclipses No(s): 69, 70
State: Fading
Poor data quality. I assume poor transparency and occasional clouds, but difficult to say exactly why remotely.Attachments:
Back from the vacation. The telescope was collecting data, 2243 observations have been made for period August 14 to 23.
August 14, 2022, State: Quiescence
Eclipse No. 71, Profile: V/N/AAugust 15, 2022, State: Quiescence
Eclipse No. 72, Profile: V/N/A
Eclipse No. 73, Profile: V?/N/AAugust 17, 2022, State: Quiescence
Eclipse No. 74, Profile: ?/H/? – Intermittent data.August 18, 2022, State: Quiescence
Eclipse No. 75, Profile: U/N/A
Eclipse No. 76, Profile: U?/N/AAugust 19, 2022, State: Rising
Eclipse No. 77, Profile: U/L/S – Accretion disk becomes bright.August 20, 2022, State: Outburst
Eclipse No. 78, Profile: U/L?/SAugust 21, 2022, State: Outburst
Eclipse No. 79, Profile: U/L/PEH
Eclipse No. 80, Profile: U/L/PEH
Post-Egress Humps developed at the peak of the outburst, peaking at phase ~ 1.125.August 22, 2022, State: Fading
Eclipse No. 81, Profile: U/L/S (brightening at a late phase due to the overall fading)August 23, 2022, State: Fading
Eclipse No. 82, Profile: U/L/S (brightening at a late phase due to the overall fading)Max
Thanks, Jeremy! Good test for the autonomous operation. Looks like our scripts are now handling most of the software/hardware random bugs. At this point, I simply define the object, area of the sky and the A1 telescope wakes up, cools down, homes the mount, centers the focuser, slews, begins the imaging plan when the object is visible, etc – once the roof opens. The server in London data center pulls all the FITS in the morning, does photometry and I get e-mails with BAA/AAVSO report files. No interaction required whatsoever except for to produce the charts. Hopefully just a little more effort with the web UI interface and we can begin serving time for BAA on it.
I see that for some reason the most interesting curve from August 21 with PEHs has failed to upload. I’m attaching it here.
Max
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Very intermittent data will be uploaded during the next few days, won’t post charts.
MaxAttachments:
I had a look at the AAVSO curve, dominated by Max’s data of course (impressive). The last period 2459700 to present reminds me of an ER UMa star in that there are two bright outbursts with a series of smaller ones between. The brighter outbursts seem to be 70 days apart.
There are no TESS observations unfortunately.
Ive added it to my SLOOH watch list for Canary.
Stewart
With a screen shot
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Thank you, Stewart.
Eclipses No(s): 83
State: Quiescence
Got some poor quality data despite the clouds, U?/N?/A profile.Attachments:
Thank you, Jeremy! The mystery of CG Draconis has to be solved!
Eclipses No(s): 84, 85
State: Quiescence
U/N/A + ?/N/? eclipses, typical for quiescence. Post-egress hump peaking at phase ~ 1.2 on the first eclipse, coinciding with the reappearance of the bright spot on the other side of the eclipse.Attachments:
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