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After a 2-week pause caused by a patch of bad weather, loss of power supply and Internet connectivity at the observatory – all at the same time…
Eclipses No(s): 92
State: Rising
Appears to be U/L/S eclipse, similar to the previous one (#91), just skewed due to rising magnitude. Old epoch is far off the minima, needs revisiting.Max
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In outburst, ~ 0.15 mag flickering.
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Unfortunately, the weather has been really horrible all these days… Managed to get a few data points here and there, but not enough to build a curve, so I haven’t been posting. Tonight the clouds have interrupted the session only early in the morning – so good data.
Eclipses No(s): 91
State: Rising
Typical accretion disk-dominated U/L/S eclipse. We need a new period/epoch analysis, as the old one appears to be inaccurate.Max
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Robin,
Incredible result! I wish there would be a workshop or something showing how this was done – from observation to processing.
Max
Eclipses No(s): 90
State: Fading
U/L/S eclipse, PEH has disappeared.Attachments:
Gianni, I am afraid I will be unable to understand Italian – but looking forward to an article in English. 🙂
Eclipses No(s): 88, 89
State: FadingTwo U/L/PEH + U/L/PEH eclipses. Accretion disk fading in brightness. There are two short post-egress brightenings of the same profile on both eclipses, peaking at exactly phase 1.14, so this is likely a PEH feature and not a flickering artifact. This is easily seen on the phase plot as post-egress magnitudes are a little different and one PEH appears to be on the top of another one. The bright spot appears to be compact or partially obscured by something, as it is not a smooth hump.
Max
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Eclipses No(s): 87
State: FadingSurprising curve today on the way down – broad U-shaped profile, highly asymmetric, no orbital hump. Very extended post-egress brightening all the way from phase ~ 1.15 to 1.50 – almost as if the bright spot is on the wrong side of the eclipse. Assuming this can be called a post-egress hump, except that it is a very broad one, this curve can probably be classified as U/L/PEH. We have seen this profile during the fade on June 30th except that back then the PEH was much narrower.
What causes such variation of minima shapes – this “U” is extremely broad – bright and very extended accretion disk?
Wild speculation, again, on the magnetic theme. Can CG Dra’s WD magnetic field switch on and off, sometimes turning the system to something resembling a polar? The patchy stream of material can block the bright spot at phase ~ 0.8, resulting in lower ingress flux, compared to egress. This U/L/PEH curve is somewhat similar to HU Aqr and SDSS J093537.46+161950.8 which Hardy et al. (2017) describe as a “typical polar.”
Seeing overall was very good tonight – there are interesting flickering oscillations towards the end of the curve. Note some fast flickering episodes reach close to 0.2 mag in amplitude.
Max
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Gianni, it would be interesting to read more about your atmosphere project. If sky pollution is an issue then a lot of projects are to be done in the solar system, including automating observations of the solar photosphere and chromosphere, nightly monitoring of the planets and the Moon, and so on. Lots of inspiration in the BAA Journal.
Eclipses No(s): 86
State: OutburstV/L/S-type eclipse (V-shaped, low or none orbital hump, symmetric), expected for the outburst. I find this state to be the most interesting, as almost every light curve is unique. Very good data quality with check star sigma ~ 0.016 mag, revealing the flickering dynamics. Interesting “fading” wave after the egress.
Max
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Gianni, it is getting more and more difficult indeed. Where I live (Bortle 8-9) I can barely see anything at all, yet still visual astronomy is possible with a night vision device. Even through a small refractor it is possible to see Markarian’s chain, M1 and other wonders via IR-filtered view, so not everything is lost. I don’t think I would manage to collect these 20K+ observations had not the telescope been fully automated. Building “robotic” observatory was really the key for me, so the telescope might as well be somewhere else under the dark and steady skies, as I don’t touch the hardware at this point. The romance of having hands-on hardware experience is lost, but this allowed me focus on data pipelines, processing and, also, trying to understand the physical nature of the star, which is more intriguing than messing with the hardware for me. I think if you’re really after building light curves then accessing a remote observatory is a plus.
Max
Alas, not yet. Even sunny Spain has weather.
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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:
Thank you, Stewart.
Eclipses No(s): 83
State: Quiescence
Got some poor quality data despite the clouds, U?/N?/A profile.Attachments:
Very intermittent data will be uploaded during the next few days, won’t post charts.
MaxAttachments:
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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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
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:
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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By the way, for some reason the BAA site keeps logging me out – I have to log in every day and grant permissions to be able to post. Quite inconvenient. Sorry if this is irrelevant to the member areas problem.
Max
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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