Waiting for T CrB aka the Blaze star

[Nik271]

The variable star event of the year will be the eruption of T Corona Borealis, predicted sometime between now and September.  Barring a galactic supernova this one is as good as it gets for us visual observers - from magnitude 10 to magnitute 2 for a few brief days. With the sorry weather we have this year I expect I will be clouded for the main event and so used a brief spell of clear sky tonight to shoot several images of Corona Borealis with my Canon 250D. Just for the record to compare before and after.

20 x 3 second frames, no tracking, stacked in DSS. 

Edited May 28 by Nik271

[josefk]

i have every intention of making a similar "before" empty sketch @Nik271 for the same before and after comparison/satisfaction myself (weather willing) 👍

[lunator]

I am wait with some anticipation for this. I have only looked at this area with Binos recently but I hope to get a look t it through the scope soon. 

Cheers

Ian 

[jjohnson3803]

Somebody somewhere (BAA variable section maybe?) was predicting early November 2025 for it to blow.  At least I think they wrote 2025; I'll have to look for the reference.

Probably best to keep monitoring it though.

 

 

[Nik271]

It was revised for 2024 based on dipping of the light curve:

https://www.aavso.org/news/t-crb-pre-eruption-dip

[bomberbaz]

I accidentally deleted my spectroscopic image of the red giant that surrounds the white dwarf. It was very dim and to get a spectrum using lo-spec grating and a 150 quattro required binning which is not generally recommended for spectroscopy but I am very much looking forward to the WD going boom

If I get chance I am going to grab some new (pre-boom) data and will happily post up my results for anyone interested.  

An FYI it has actually DIMMED as part of it's pre-eruption cycle and according to AVVSO this is higher than previously recorded. Maybe improved equipment and recording methods!  A lot of the stuff gets involved and starts to go above my head if I am honest.  Link below, worth a read.

Announcing T CrB pre-eruption dip | aavso

EDIT, sorry only just realised Nik has already posted link, sorry.

Anyway, currently ~ mag 10 but will be around the same (or brighter maybe) than polaris upon the WD erupting.

Light the fuse and stand well back.

Steve

Edited May 29 by bomberbaz

[Paul M]

It isn't entirely lost on me that my Allsky camera is, perhaps, well suited to recording the brightening of T CrB. The overnight timelapse could potentially capture the main event if the timing is right, not to mention the weather!

Edited May 29 by Paul M

[bomberbaz]

13 minutes ago, Paul M said:

It isn't entirely lost on me that my Allsky camera is, perhaps, well suited to recording the brightening of T CrB. The overnight timelapse could potentially capture the main event if the timing is right, not to mention the weather!

 

Definitely make sure it is in your sky area of interest Paul.  I have no doubt that if you manage to capture the eruption it will be of some scientific interest to some organisations. 

[Geoff Lister]

Last night T CrB was still about magnitude 10. Epsilon CrB is about magnitude 4

Geoff

[Nik271]

Imagine the moment as it brightens some night, it's supposed to be very quick. It will be awesome to see that!

[Paul M]

1 hour ago, Nik271 said:

Imagine the moment as it brightens some night, it's supposed to be very quick. It will be awesome to see that!

Yes, someone, somewhere will land lucky! I do wonder if the roughly 2 frames per minute of my allsky camera will miss much of the action, assuming it happens in our night and it's clear?

[lukebl]

Much as I’d love to see this event, I’m wondering what the real evidence is that it’s about to ‘blow’.

Given that there have only been two previous reliably-observed outbursts, 80 years apart, can we really be sure that the next one will also be 80 years on? Two events is hardly a reliable statistic sample. Maybe the next one will be 100, 200 or 800 years later?

Just wondering.

[JeremyS]

2 hours ago, lukebl said:

Much as I’d love to see this event, I’m wondering what the real evidence is that it’s about to ‘blow’.

Given that there have only been two previous reliably-observed outbursts, 80 years apart, can we really be sure that the next one will also be 80 years on? Two events is hardly a reliable statistic sample. Maybe the next one will be 100, 200 or 800 years later?

Just wondering.

Both times there was a pre-eruption dip when the star faded by about a mag in the year before. It now appears to be in such a dip. Also the spectrum has changed. But, indeed it might not repeat exactly this time round.

This is a bit dated now, but this is something I wrote last year about observing T CrB:

https://britastro.org/section_news_item/get-set-for-the-next-eruption-of-the-recurrent-nova-t-coronae-borealis

[jjohnson3803]

Took a quick look with my binos last night, just in case.  

 

 

[Paul M]

I'm starting to hope that T CrB holds it's horses until late August. The last week in August, as the Moon is between last quarter and new, so rising late on, the nights will be drawing in again and CrB will still be relatively accessible. I'm not sure how long the main thrust of the brightening will take, but hopefully it'll start just as the sky darkens so I can capture it nicely. Just need some clear skies!

I've been playing with allsky camera settings, including binning 2x2, it gives a brighter image and much smaller file size. Meaning I can get three frames per minute, as opposed to just 2 un binned frames. Unfortunately the binned images are much less pleasing to the eye and the lower resolution doesn't led itself to zooming in on a small region.

It'll exquisite in 1x1 anyway...

 

 

 

 

[josefk]

I achieved the easy bit last night - a "before" observation and sketch of the FOV with T CrB located and "matched" to the magnitude of one or two field stars and clearly dimmer than one or two other field stars so i'm all set :-).  

PS - i'm totally rubbish at comparing magnitudes!  "obviously brighter", "obviously dimmer" and "about the same" is as scientific as it gets...

[josefk]

tidied sketch from last night with key (for me) comparison stars for the future...

and the "asterism" that locks me in and the key "magnitude companions" highlighted:

All four of those nearby stars looked the same to me so i clearly have no discernment between mag10.1 and mag11.3. hahaha.

Fingers crossed now for opportunities for a "during" observation later.

[Nik271]

I looked at TCrB last night at about midnight and estimated it at between 10.1 and 10.5. To my eyes it was brighter than the double of 10.8-10.6 magnitude stars south east of it.

Intriguingly the B band magnitude observations from AAVSO have dropped down to mag 12, so the dimming continues. Eruption should be soon... Hoping for a long clear spell!

[bomberbaz]

Has anyone gone and lit the fuse yet, for those oldies thaat remember this is like waiting for your dad on bonfire night!

[Ags]

I really hope my grandson comes over here with my star analyser really soon!

[Nik271]

I looked for T CrB last night in the twilight, could not see it as the sky was still too bright. I could see down to mag 8 stars around epsilon CrB so the wait continues.

[Mr Spock]

Not had a look at this yet. Just ran myself a chart off AAVSO chart plotter though. 3° is perfect for the 4".

I've modified this so you can't copy it (copyright) - go to the AAVSO website to get one. Link is on the chart 

[JeremyS]

Here’s something about the last eruption in 1946 I wrote, published yesterday: https://iopscience.iop.org/article/10.3847/2515-5172/ad566b

[MalcolmP]

On 12/06/2024 at 23:18, bomberbaz said:

Has anyone gone and lit the fuse yet, for those oldies thaat remember this is like waiting for your dad on bonfire night!

I had a good view last night (14-15June) for a short time before clouds and rain ended the party.
Sadly the blue touch paper got soggy and I was unable to light it for you

While waiting :- I have been watching the approach of (2)Pallas which is now just 1deg ENE of T CrB  ( I posted a Stellarium track of the event somewhere on the forum  a short time ago, I'll edit in a link when I find it !) EDIT: https://stargazerslounge.com/topic/422548-asteroid-2pallas-in-hercules-with-a-dslr-fixed-on-a-tripod/

Here, midnight1415, is a stack of 2sec subs using a Canon 60d+135mm lens. Yellow marks Pallas last night, green arrow where it will be tonight. (shh,, dont tell the cloudgods )

An interesting** colour effect when I import the DSS autosave .FIT into ASTAP for platesolving
( **Anyone remember the constellation portraits by Akira Fujii in S&T a long time ago ?)

 

 

Edited June 16 by MalcolmP

[Nik271]

TCrB looked dimmer to me last night (1am UT 18/06). It seemed similar in brightness to the 10.6 comparison star which 15 arcmins north of it on the AAVSO chart.

Forgot to look for Pallas though :-(

Edited Tuesday at 09:58 by Nik271