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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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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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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): 61, 62
State: QuiescenceCG Dra can be very deceptive. Look at how different eclipse profiles are, separated by just 4 hours. Poor quality data, combined with flickering due to the bright spot on the accretion disk of the white dwarf makes the second eclipse appear almost symmetrical and much deeper than the first one. Wild flickering creates bumps in the orbital hump, sometimes right before the ingress (2nd eclipse). Random patterns due to the measurement uncertainty at the eclipse minimum (1st eclipse), then, removes or adds depth, and flickering at the egress (2nd eclipse) may occasionally play another joke. I think this is what is happening here. Two asymmetric eclipses with normal ~ 0.1 mag orbital hump (U/N/A), distorted by uncertainty and flickering, so they appear to be different.
A question: should I continue assigning eclipse types just as they appear on the light curve, like I did before, or should I compensate for these distortions due to poor quality data? There is more value in compensating, but if I do this, I’ll need to reclassify all poor-quality eclipses I’ve filed earlier (Whew…)
It would also be interesting to correlate FWHM with sigma. The night was pretty clear and dark. There was no extreme in temperatures. Why photometry quality suffered – I don’t know.
Max
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Eclipses No(s): 60
State: Quiescence
V/N/A. Intermittent clouds.Attachments:
Eclipses No(s): 59
State: QuiescenceCG Dra back to quiescent state with a typical U/N/A eclipse, normal ~ 0.1 mag orbital hump amplitude indicating a mix of accretion disk and bright spot components. Mediocre data quality due to the clouds. Roof was closed 9 times this night, so this was a good test of automatic telescope wake-up routines.
Max
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Eclipses No(s): 57, 58
State: Fading
A pair of U/N/A eclipses, normal orbital hump (albeit ~20% lower amplitude), asymmetric.Attachments:
Eclipses No(s): 55, 56
State: Fading
CG Dra is now fading after the bright outburst, reaching normal outburst luminosity. Two highly symmetric U/L/S-type eclipses signifying that the accretion disk is still bright, hot and ionized, concealing the bright spot.
MaxAttachments:
Eclipses No(s): 54
State: Bright outburst
U/L/S-type eclipse profile: U-shaped, low to none orbital hump, symmetric.Attachments:
