T CrB Time Sensitive Alerts Forum thread

Affiliation
American Association of Variable Star Observers (AAVSO)
Wed, 09/06/2023 - 18:22

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

 

Affiliation
American Association of Variable Star Observers (AAVSO)
? T CrB Brightening

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)

Affiliation
American Association of Variable Star Observers (AAVSO)
Please double check observations

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

Affiliation
American Association of Variable Star Observers (AAVSO)
False Alarm!

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

Affiliation
American Association of Variable Star Observers (AAVSO)
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

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Filter Problem

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