This forum thread is for posts about T CrB when the outburst occurs (predicted for 2024). Be sure you are logged in to your AAVSO web account to post to this forum. If you don't have an AAVSO web account, see below.
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Submitting observations
Be sure you are logged in to your AAVSO account and have an AAVSO observer code before submitting observations.
- If you have optical observations (visual, photometry) to report, submit them to the AAVSO International Database (AID) using WebObs.
- If you have spectroscopic observations, submit them to the AAVSO Spectroscopic Database (AVSpec). Note that there is an observer validation process which you must complete before you submit the spectra of your choice. Further information and documentation can be found here. We strongly recommend you complete this process as soon as possible so you will not be delayed in submitting T CrB spectra.
Questions? Contact us at <aavso@aavso.org>.
Many thanks, and good observing,
Elizabeth O. Waagen, AAVSO HQ
From my images this morning in BVR it appears that T CrB is almost 2 mags brighter than my last observations on 2/1/24. Even though my images appear ok and my photometry appears ok the last observation posted was 10.0 Vis about what it has been in V and 2 hours after my observation. The previous digital mag was 2.5 hours before my observation at 10.061V. I am getting 9.120B (err 0.15), 8.279V(err 0.14), 7.868R(err 0.005). I have not submitted these to Webobs yet. I am hoping that someone where T CrB is visible can confirm.
Barbara(HBB)
Barbara,
This quite exciting. Could you please double check your images and reduction? There is a visual observation about 0.1 day later that contradicts these measurements. I've also reached out to the visual observer with a similar request.
Thank you!
Brian Kloppenborg
Looks like it may be a false alarm. When I checked the star that I imaged after T CrB in B,V,R, the avg. ADU for the star was about the same in each filter so it appears that even though the filter wheel was reporting the filter I selected, it actually was not moving to the proper filter. The V and R ADU was identical and the B ADU was reading a lot brighter. So chalk this up to mechanical error but Keep Looking Up!
Barbara
I’d like to thank…
Barbara,
I’d like to thank you for both reporting these observations and taking the time to thoroughly check your work. Had this been the real event, your timely report would have been critical in mobilizing astronomers worldwide to monitor this truly once-in-a-lifetime event.
For the record, I’ve had many stuck filter wheels during my career and they always lead to some serious head scratching. If your filters are dirty, you can often pick them out by looking for dust rings in the images. However, if your filters are clean, it gets a lot more difficult. Could you tell us a bit more about what you did to figure this out?
Have a great weekend!
Brian
Confirm false alarm
https://www.cloudynights.com/topic/909460-recurring-nova-t-cbr/?p=13240750
Robin
When I measured the magnitude of the star after I imaged T CrB, 3C 273, I saw that the magnitude was off compared to other observations in WebObs. I had imaged in multiple filters and confirmed that the ADU on a comp star in that image was the same in all filters. I returned to my T CrB images and measured the comp star in B,V,R and found that the ADU was the same across all filters. I compared this to my last "normal T CrB" images from 2/1/24. The ADU in Blue was about half that of the V filer.
It helped that I had not only multi-filter observations but also multiple images in each filter. My routine is to take 4-5 images in each filter, perform photometry on every image, and then report the average magnitude. It would have been difficult to detect the problem if I only had one image in one filter.
Another thing that can be learned from this problem is how to rapidly report the outburst. It should be submitted to WebObs and posted to this forum so that email notifications can be sent to those who subscribe to this particular forum thread. I recommend that those who are monitoring T CrB subscribe to this thread.
Barbara
Could someone at HQ remove the extreme error at
2460407.39581 <15.562
It is obviously an error and with so many T CrB observations in the db it takes a long time rescale the plot to remove it from the plot window. Thanks much.
Jim (DEY)
Could someone at HQ remove the extreme error at
2460407.39581 <15.562
It is obviously an error and with so many T CrB observations in the db it takes a long time rescale the plot to remove it from the plot window. Thanks much.
Jim (DEY)
Hi Jim,
We appreciate your letting us know about the discrepant T CrB observation. It has been flagged so it will not show in the light curve generator, and I have contacted the observer so it may be corrected.
Please let HQ know directly (aavso@aavso.org) about discrepant observations found in the light curves instead of via the forum. Thanks!
Good observing,
Elizabeth
The T CrB sequence has been revised.
It is important that you update your charts as soon as possible, so everybody is using the same charts when the star goes into outburst.
We have created customized charts and they are available at:
https://www.aavso.org/tcrb-charts-photometry-tables
The A-scale chart we created includes the stars that we have selected as the best ones to be used when the star gets brighter than 8.8 mag.
When it is fainter than 8th magnitude you can use the B-scale chart we recommend.
If the star gets fainter than 10.7. or if you need a deeper chart, we recommend the D scale chart that we linked.
Good observing!
The magazine article about T CrB caught my attention early this year and I decided to give variable star photometry a try. I’ve imaged T CrB at every opportunity since late February as I’ve attempted to understand and improve my techniques and confidence in the accuracy of my data.
Since the sequence has changed, would it proper to go back and rerun all the past data using the new sequence?
Thanks!
The 102 comparison star that had been removed from the B and D scale charts has been restored as of 16 July 2024. Charts and Photometry Tables reflecting this revision are available from this page: https://www.aavso.org/tcrb-charts-photometry-tables
They may also be created using the AAVSO Variable Star Plotter (VSP).
Please be sure you are using the latest charts for T CrB. Also, please be sure to read the notes in the Photometry Table for each scale chart - they are very important!
Many thanks, and good observing,
Elizabeth Waagen, AAVSO HQ
T CrB AAVSO pre-made charts and information on comparison stars, as well as information on making your own customized charts, may be found here: https://www.aavso.org/tcrb-charts-photometry-tables
When the AAVSO forums switch to the new version later in September, a notice will be posted in this thread giving the new URL.
Many thanks, and good observing,
Elizabeth O. Waagen, AAVSO HQ