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James, this might be related to the ongoing VizieR/SIMBAD database issues I mentioned on another thread. It’s certainly preventing AAVSO from automatically downloading chart and sequence data.
Does the ZWO photometry programme state where it gets its data?Hello Connor,
have a look at the VSS Eclipsing Binary Handbook which is available online.
Section 4. “Which Eclipsing Binaries to Start With?” lists some EBs you could try.This would be a good start to test out your Seestar. Just keep in that the inbuilt photometry programme has some flaws which mean that its results might not be reliable. There is another forum thread running on that subject.
Jeremy
Hopefully someone can provide a chart, Mel.
The underlying problem is that AAVSO variable star plotter draws data from VizieR/SIMBAD. Both have been experiencing significant outages in the last few days. Apparently the former due to intense bot activity and the latter due to a global security breach at the U of Strasbourg which hosts it.Hello Connor,
In addition to Ian’s q’s, are you interested in visual photometry or digital? If the latter, there are some targets here to think about if you are starting out: https://britastro.org/vss/VSS_CCD_Target_list%20ed%204_20190723_V3.pdf
Jeremy
I am also hopeful that we shall see progress by the smart scope companies in producing easy to use photometry pipelines. But the key will be that they must make the methodology behind the pipeline available to all to scrutinise. At present, people are having to do trial and error experiments to understand what the ZWO software (in this case) is doing. And in doing so, stumble across basic issues like saturated star images.
And great to hear you plan to continue with the visual observing, Mel! As Andy Wilson noted, the number of VSS photometric observers is holding up well, but there is a slow decline in the number of visual observers in the mix. IThe continuity of the historical visual record is itself a scientific resource.
Great stuff, Steve.
There are people doing daytime imaging of the field of T CrB. Though I am not aware of anyone using a Seestar for that, ARne Henden is using a Newtonian stopped down to 50mm, a long focal length Seestar 50 🙂
Here is a discussion on daytime imaging: https://britastro.org/forums/topic/24-hour-monitoring-of-t-crb
Hello Steve,
Looking at both the BAA VSS and AAVSO data it has been brightenin g over the last 25-ish days, but it looks like part of the normal 226 day period modulation.
VSS LC from 1 Jan 26 attached.
Keep looking though – you are doing great work. I have lost it from my site.
Go well!
JeremyAttachments:
Apparently it has levelled off at mage 1.0 according to this ATel: https://www.astronomerstelegram.org/?read=18114
Christopher,
more and more people are using Seestars and other smart scopes for photometry effectively (e.g. David Conner has written about it in recent VSS Circulars). This is a good thing. However, as Andy pointed out, we do need to ensure the photometry is reliable. We know from Steve Knight’s extensive work on T CrB that at some point dodgy photometry was produced when software was updated – he spent a LOT of time digging into the reasons.
It also depends on what the photometry is subsequently used for. “Quick and dirty measurements” might have their place in some projects, for example detecting a nova eruption, but problems start when unreliable data are uploaded into databases from which the data are subsequently extracted for analysis. We need to ensure that the databases containing amateur photometry, like the VSS database, retain their high reputation in the astrophysics community, including by professional astronomers.
Go well!
JeremyI am actually OK with the term amateur astronomer and that is how I describe myself. “An amateur is a person who engages in an activity, sport, or art for pleasure, passion, or personal interest rather than for financial gain or as a profession” sums it up for me.
But whilst we are on the subject of terminology, one term I dislike is “citizen science”.
ATel 18097 today has an intriguing title: Extreme Velocity Gradients in the Atmosphere of Betelgeuse: Is Another Dimming Event Imminent?
It seems to be down, David. Maybe because it’s hosted in Russia?
I usually access via VSX, but that link is dead too.
VizieR has GCVS 5.1 data which are accessible.I’ve always been slightly irritated by calling T CrB “The Blaze Star” and had assumed it was a comparitively recent Americanism. Apologies to all Americans for my prejudice. It turns out I was wrong, it was first used in the Sept 15th 1869 edition of English Mechanic & Mirror of Science. I will now be using the term at every opportunity!
Many older atlases have it identified as Blaze Star.
But not to be confused with Blaze Starr: https://en.wikipedia.org/wiki/Blaze_Starr
Possible beryllium emission detected in UV: https://www.astronomerstelegram.org/?read=18073
Three of the authors have another paper on superoutbursts of YZ Cnc based on TESS photometry and long-baseline ground-based observations.
The ApJ accepted manuscript is available here.
Multiple Seestar T CrB light curve beginning July 4th 2024. This curve is derived from 397,667 (ish) exposures up to September 9th 2026. There are 264 data points here each derived from a stack of as much of the night as I can manage. Processed with Pixinsight and differential photometry with AstroImageJ. Exposures are 2-30 sec. Now investigating how my green channel magnitude matches V magnitude.
Good to see you persevering with this, Steve. Keep going!
I changed the title of this thread not Jodrell Bank NOT closed following the PM’s statement.
However, news emerged from the government yesterday that throws this into doubt. The article “Jodrell Bank’s e-Merlin network still faces closure in 2028” suggests that the govt still upholds the STFC funding reductions.
In an ApJ paper on ArXiv, Brad Schaefer analyses available data on V1405 Cas and concludes, among other things, V1405 Cas is not a Type Ia supernova progenitor.
V1405 is still mag ~13 and above quiescence.
This MNRAS submission on The First Multi-Messenger Nova: External Shocks, TeV Photons, and Neutrinos in the Next Eruption of T CrB takes another look at timescales for its eruption recurrence.
Taking various factors into consideration, the authors come up with a recurrence time-scale of Trec ≃ 80±12 yr.
However, they note that if substantial weight is instead assigned to the proposed historical eruptions of T CrB, and the 1217–1787 interval between eruptions is assumed to contain seven recurrence cycles, the resulting recurrence history implies a much narrower characteristic time-scale of ≃ 79–80 yr with a dispersion of only ∼ 1–2 yr. The latter is in line with Schaefer’s predictions.
We are now at T(last eruption) + 0.6 years and we keep looking…..
