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March 2021 Supernova thread

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#1 alanjgreen

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Posted 03 March 2021 - 08:30 AM

I was out last night (before the big moon came up) to try to spot some supernovae while the sky was dark.

 

I had mixed results...

 

1. First up was SN2021dap in PGC020072

dap.jpg

 

2. Next it was SNAT2021cwc in UGC3502

cwc.jpg

 

3. SNAT2021blu in UGC5829 was a fail

 

4. SN2021J in NGC4414 was a success. It still bright and easy to see.

 

5. SN2021biz in NGC4227 was a fail

 

6. SN2020qmp in UGC7125 was a fail too.

 

The last two were severely affected by the brightening eastern sky that they were sitting in, so we wait for the next clear night to try again!

 

Alan


Edited by alanjgreen, 03 March 2021 - 08:32 AM.

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#2 timokarhula

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Posted 05 March 2021 - 09:34 AM

I had not seen SN2021J in NGC4414 this winter until last night.  I was surprised to find out that SN2021J was still a direct vision object with my 12-inch and 300x.  The galaxy had a double nucleus with the supernova as the fainter component, four arc-seconds south of the true nucleus.

 

/Timo Karhula


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#3 Dave Mitsky

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Posted 05 March 2021 - 04:30 PM

I haven't been checking on current supernovae for the past couple of months and will have to give SN2021J a try, possibly tonight. 



#4 Dave Mitsky

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Posted 06 March 2021 - 12:50 AM

Well, despite some of the forecasts, it was far from clear here tonight but it was cold and windy.



#5 alanjgreen

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Posted 17 March 2021 - 09:47 AM

I have managed a couple of sessions this week (on 13th and 16th March).

 

13.1  On the 13th, I was able to view SN2021bbz in PGC036639 for the first time... I saw a double core but could not separate the dots. The 18.2mm eyepiece performed best on this target with my Night Vision device.

bbz.jpg

 

13.2  I also observed (not for the first time) SNAT2021J in NGC4414.

 

13.3  I was unable to find SN2021biz in NGC4227, I have had several attempts at this one without success.

 

13.4  I also successfully viewed SNAT2021K in PGC048870 (not for the first time).

 

16.1  On the 16th, I observed SNAT2021J in NGC4414(once again).

 

16.2  I had a harder time viewing SN2021bbz in PGC036639, the conditions were not as good.

 

16.3 I managed to get occasional glimpses of SN2021bbm in NGC2959 (new one for me) but it was a tough one for sure. The 35mm eyepiece performed best on this target with my Night Vision device.

bbm.jpg

 

16.4  I got a flash of a glimpse of SNAT2021cwc in UGC3502 (not my first viewing), but it was very hard and I only had one glimpse in a few minutes of trying, so this one is on the way out...

 

16.5 I did manage to view SN2021dep in PGC1813600, the galaxy was hard to find but the tight double dot was there. The 18.2mm eyepiece performed best on this target with my Night Vision device.

dep.jpg

 

Clear skies,

Alan


Edited by alanjgreen, 17 March 2021 - 09:48 AM.

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#6 StanH

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Posted 18 March 2021 - 05:28 PM

On March 6 I took a look at NGC 4414 for SN 2021J with the 17.5-inch.  What I thought was the supernova does not match where it should be.  Haven't had a chance to take another look because of the weather. 

 

Here are my notes:

 

30mm (61x):  NGC 4414 was not seen.  9mm (202x):  NGC 4414 was very elongated north to south.  It had a faint core with what was believed to be the supernova offset from the core.  9mm + 2x Barlow (404x):  There was a stellar object brighter than what was believed to be the core barely resolved from the core and offset to the east.  It was obviously not at the center as it was on the edge of the central area.  The  stellar object was obviously trailing the core as the field moved.  It was also brighter than the core.  The problem is the supernova is about 4” south and 1” west of the core and between the core and a superposed star.  So what was I seeing that was off-center?  Is the core off-center?  Checking my notes the only other time this galaxy was observed was with the 8-inch many years ago.  There was no mention of the core.  Apparently, I never viewed SN 2013df in this galaxy, but did take images.  The stellar core does seem to be a little off center to the east.  The superposed star might be too faint.  Most likely I did see the supernova, but it was what I thought was the core.  Need to look at this again, but would have to wait until next weekend; however, the newest forecast calls for it to be cloudy and rainy late next week into the weekend.

 

My other concern is that superposed star some 10" SSW of the core.  Just how bright is it?  It is too embedded to get reliable photometry on my images of the galaxy from 2013, but a trick to rotate the galaxy 180 degrees and subtract the two images came up with magnitude 14.3V.  Gaia shows it 14.4G.  If those values are right, most likely what I saw were the superposed star and the core.  Also, the brightness of the supernova may have been reported too bright due to contamination from the host galaxy.  One color image posted to David Bishop's page and dated March 6 shows the supernova fainter than the superposed star.  It may be that some reports of the supernova may actually have been of this star.



#7 timokarhula

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Posted 19 March 2021 - 07:19 AM

I observed SN2021dov in CGCG 005-038 (Hydra) last evening with my 12-inch Dob and 188x power.  I could easily see the supernova but I was not sure about seeing the galaxy itself.  SN2021dov overpowered the galaxy.  I estimated SN2021dov having the same brightness as the star 71" SW, that is magnitude 14.2.

 

I could not see SN2021K in MCG +6-30-84 (CVn) later in the night.

 

/Timo Karhula


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#8 EmeraldHills

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Posted 19 March 2021 - 09:19 AM

Looking forward to trying to observe PNV J23244760+6111140 tonight. Exciting stuff! (Thanks to GaryShaw who tipped me off.)

23 24 47.73    at  +61 11 14.8

 

I did a quick video about it here.

 

http://www.cbat.eps....60 6111140.html

2021 03 18.4236

Discovered by Yuji Nakamura, Kameyama, Mie, Japan, on four frames (15-s exp. limiting mag 12.0) taken by 135mm F4.0 lens + CCD. Nothing is visible at this location on the frames taken on 2021 Mar. 14.4253 UT (15-s exp. limiting mag 13.0) by same instrument. The object is located very close to a W UMa type eclipsing variable star CzeV3217 (Mag. range 14.870 - 14.960 V, AAVSO VSX).


Edited by EmeraldHills, 19 March 2021 - 12:22 PM.

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#9 timokarhula

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Posted 19 March 2021 - 09:46 AM

PNV J23244760+6111140 is a classical, galactic nova.  Not a supernova, but still very interesting.  It is now designated as N Cas 2021 in AAVSO.  Nova Cassiopeia can very well reach naked eye magnitude in coming nights.  I was not aware of its existence last night, so I missed Nova Cas.

 

/Timo Karhula


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#10 EmeraldHills

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Posted 19 March 2021 - 09:53 AM

PNV J23244760+6111140 is a classical, galactic nova. 

<...snip...>

Thanks Timo. I'm relatively new on the scene here. (Even though my registration at CloudyNights dates back to 2006, I've really only become an active observer in the past 3 months... so I have a grand total, really, of 10 observing sessions under my belt so far hahaha sadly.) But please help me catch up - what would distinguish a galactic nova from a super nova? Is it just a matter of degree? An increment?



#11 timokarhula

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Posted 19 March 2021 - 10:14 AM

Hi Doug L. (EmeraldHills).  Well, I'm not an expert in variable stars, but I'm more in to deep-sky and comets.

 

Simply put, ordinary novae do not destroy themselves totally and can therefore burst several times in their life-times.  They may increase their brightness by about 10 magnitudes or more during an eruption.  Novae occurs several times a year in our Galaxy.

 

Supernovae are believed to destroy themselves completely and leave only a neutron star or a black hole as the remnant, plus a surrounding nebula that was created by the explosion.  Supernovae should brighten by about 15 magnitudes or more.  That is about 100 times more than an ordinary nova.  Supernovae should happen about once every 100 years in the Milky Way, so we are some 400 years overdue now!

 

Novae and supernovae have distinct differences in their spectrums.  Their expansion velocities differ at least 10-fold and supernovae show spectral lines with signatures of heavy elements, and so forth.  Their mechanisms are different and I leave to others to describe them better than me. smile.gif

 

All the best,

 

/Timo Karhula


Edited by timokarhula, 19 March 2021 - 10:20 AM.

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#12 EmeraldHills

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Posted 19 March 2021 - 10:23 AM

Hi Doug L. (EmeraldHills).  Well, I'm not an expert in variable stars, but I'm more in to deep-sky and comets.

<...snip...>

VERY helpful!!!!!!!!!!!!!!!!! So part of it IS incremental. But we look forward to the spectroscopy, right? : )


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#13 timokarhula

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Posted 19 March 2021 - 10:35 AM

Its spectrum has already been obtained and investigated.  smile.gif

 

(quite technical reading..)

 

http://www.astronome...org/?read=14472

 

Actually, I have observed a lot more of supernovae (66 of them) than ordinary novae (17) because I look out in to the cosmos.  Only once have I observed a classical, extra-galactic nova,  AT2019lvm in the Large Magellanic Cloud.  That was on August 24, 2019, on my most recent trip to Western Australia. The nova was still faint, magnitude 12.9 by my estimate.  I have made many trips to the southern hemisphere but only after SN1987A in LMC.

 

/Timo Karhula


Edited by timokarhula, 19 March 2021 - 11:24 PM.

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#14 EmeraldHills

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Posted 19 March 2021 - 12:23 PM

Love it. Read this material and still think it's exciting to witness this.


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#15 StanH

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Posted 20 March 2021 - 08:30 AM

Despite moonlight, I set up the 17.5-inch last night.  Nova Cas was unfortunately too low to the northwest to see.  Probably could have seen it before dawn, but after 11 PM I was as far as I could go.

 

Turns out it was better than on March 6 with no moonlight.  This definitely was a night to have stayed up if I had the stamina.  Stars E and F of the Trapezium were perhaps the easiest I have ever seen.  Alas, the Pup still eludes me.  There is just too much glare from Sirius and reflections off the vanes.  Dug out the 8-inch, but no luck there either.

 

Reobserved NGC 4414.  SN 2021J was not visible.  Just the core and the superposed star were seen. 

 

Did not go after any other supernovae.  Mainly working on finishing up the Herschel 400 right now and reobserving some not seen since using an 8-inch over 30 years ago.

 

There is a new potentially bright supernova AT 2021gmj in NGC 3310.  It was magnitude 16.0 sloan-r at discovery.  It could get as bright as 11.9 if a Type Ia or around 13.9 for a typical core collapse assuming no host extinction.  https://www.wis-tns.org/object/2021gmj

 

Also, there is SN 2021fxy in NGC 5018 that is a Type Ia.  It could get to about 14.3.  https://www.wis-tns.org/object/2021fxy


Edited by StanH, 20 March 2021 - 08:58 AM.

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#16 StanH

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Posted 20 March 2021 - 08:12 PM

Despite moonlight, I set up the 17.5-inch last night. 

<...snip...>

AT 2021gmj is now SN 2021gmj as it has been determined to be Type II.  https://www.wis-tns....tronote/2021-93



#17 erick86

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Posted 21 March 2021 - 12:59 AM

That nova in Cassiopeia is well worth a look, especially being in the same field of view as M52. I was able to get nice views of it late this evening through my 8” dob. My northern latitude definitely is helping (for once!!!!), around 53° N. 

 

Here are my observation notes. I’ve identified the nova using light crosshairs. Hope others can get a glimpse of this one. 

 

5B3EC720-EB8F-4D13-86ED-868C8072B592.jpeg
 

Eric


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#18 Timo I

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Posted 26 March 2021 - 12:47 PM


There is a new potentially bright supernova AT 2021gmj in NGC 3310.  It was magnitude 16.0 sloan-r at discovery.  It could get as bright as 11.9 if a Type Ia or around 13.9 for a typical core collapse assuming no host extinction.  https://www.wis-tns.org/object/2021gmj

 

Here's an image from that AT 2021 gmj sn in NGC3310. I got a tip for this from Finnish astroforum and decided take a quick 30:20:20:20 min LRGB image from that 15 magnitude (?) supernova with my 6" APO refractor on March 25th. (Comparison image taken with 17" scope here.)

 

https://astrokuva.ga...B152_1200mm.jpg

 

I could have released this image in a separate message thread, but here it goes.

Please notice, I'm no supernova astro fan, but I'm just a guy looking something else to be imaged as a comparison to those pretty nebulae normally imaged.

(I could have put this image into https://www.cloudyni...605962-arp-217/ message thread too, but I guess it's more suited to have it here.)

 

EDIT: replaced the image with a text link, sorry!


Edited by Timo I, 26 March 2021 - 01:00 PM.

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#19 orionic

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Posted 27 March 2021 - 05:04 PM

I attempted to view SN2021J in NGC4414 on March 20.  In my EAA capture (98 x 8sec = 784sec stack), there is a prominent bright spot right next to the central bulge of the galaxy, so I thought I was successful.  However, I then pulled up another EAA image I had captured from July 12, 2020 (35 x 15sec = 525sec stack).  It looks just about identical to me.  So, either the supernova has been going on since July last year, or, that bright spot is something else entirely.  I have marked it on both images in my gallery here:

https://www.cloudyni...21j-in-ngc4414/

 

Looking at images that others have taken, there are some that seem to mark the same bright spot as a supernova, so I am confused.  Or more likely, I just don't have the resolution, with my equipment.



#20 StanH

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Posted 27 March 2021 - 08:46 PM

I attempted to view SN2021J in NGC4414 on March 20. 

<...snip...>

There is a superposed star some 10" SSW of the core.  The supernova was about 4" SSW of the core or between the core and this star.  See my earlier posts.



#21 orionic

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Posted 28 March 2021 - 02:11 AM

Thanks Stan, that clinches it.  As you suggested in your earlier post, "It may be that some reports of the supernova may actually have been of this star" (referring to the superposed star).



#22 Redbetter

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Posted 28 March 2021 - 08:16 PM

I wasn't able to do any March DSO observing (primarily weather), but my 1/8/21 observation of SN 2021J  in the 20" f/5 was:

"Type Ia SN 2021J in NGC 4414 in Coma Berenices.  I didn't really expect to be able to resolve this one so close to the core of a prominent galaxy with good surface brightness, but the SN proved brighter than I anticipated.  Despite mediocre seeing I was able to resolve the close N/S line of the galaxy core, SN, and a superimposed field star.  I used 278 and 357x.  ZTF shows 13.4 g mag about the time of the observation."

 

If you don't clearly see all three in order, then you are missing the SN.  




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