Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Belated July 2020 Supernova Thread

  • Please log in to reply
2 replies to this topic

#1 Redbetter

Redbetter

    Cosmos

  • *****
  • topic starter
  • Posts: 9,215
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 16 July 2020 - 07:42 AM

Stan's June thread has spilled over somewhat into July, Dave also has an M85 thread underway.   We were somewhat unlucky in getting 3 bright supernovae poorly positioned in the west leading into July.  This led to frenzied attempts to observe before targets dived too low in the bright twilight sky.  Some of us have soldiered through using smaller scopes to catch glimpses between trees.  I resorted to an 80mm to catch one...that's what happens when you are set up in what was historically a sequoia grove (all cut long ago...but still plenty of other tall trees at present...although the drought has thinned them significantly.)

 

Looking for newer stuff, I ended up targeting the opposite end of the brightness spectrum last night:  SN 2020npb in UGC 11088 in Hercules.  This one supposedly was around peak on 7/6 at 17.3 magnitude.  I didn't expect to be successful with the 20", yet I found it to be straightforward, despite being very dim.  I was having some decent seeing in this part of the sky and superb transparency in this quadrant--both were allowing me to go deep.  The SN actually seemed a little brighter than a 17.1 mag field star preceding it, which was readily seen.  Both could be held/locked in AV.  The 16.3 B mag galaxy was unmistakable, along with its general structure/orientation and semi-stellar core.  The SN very slightly precedes the brighter central major axis (which is one of the two arms of this barred spiral.)  Unexpected successes like this are always satisfying.  I tracked down a couple of other galaxies nearby to the south west that I had penciled into Uranometria...unfortunately I did not go deep enough because I was seeing at least one dimmer, and trying to pin it down, when I realized three of the targets I was after at the time were trailing it, and substantially brighter.  


  • Inkswitch, KidOrion and happylimpet like this

#2 Redbetter

Redbetter

    Cosmos

  • *****
  • topic starter
  • Posts: 9,215
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 22 July 2020 - 02:29 AM

Continuing with the really dim stuff to try:

 

Looks like SN 2020ogn in ESO 597-36 (listed as "anonymous" at present) has just been classified as of 7/21.    The magnitude on 7/9 was given as 17.1.  It should be following the core by roughly 4-5".  This galaxy in Capricorn is perhaps better known as Hickson 87A which I coincidentally observed on 6/21/20 as ~4:1 elongated SW/NE...no SN at the time.   My notes say the core was not visible despite central brightening, so if I see something stellar it will be the SN.  Classification report says it is a Type Ia, a week past maximum at 0.027 redshift.  That would have yielded a peak of ~16.1 mag, and my projection is that it might be about 16.6 to 16.7 magnitude tomorrow night. 

 

There is another dim one in Pegasus:  AT2020nxt was 17.2 mag on 7/3.  Classification on 7/15 gave it as a Type Ibn but with "redshift" uncertain and about 10 days since explosion...an underestimate since it was detected 12 days prior.  This one is scheduled for Hubble follow up imaging since it is interacting with the star's circumstellar medium.  It precedes the center of a galaxy by about 4"  and it follows a 16 mag star (with a mid 17 mag star in between.)   Galaxy designation is 2MASXJ22373660+3500074 (Internal LEDA PGC designation is 3966035.)  This is north of UGC 12121 a considerable distance.  I am not sure if the galaxy will be visible.  It looks like it will be about 17+ mag.

 

Finally, there is one getting low in the sky, SN 2020oha in Ursa Major.  This Type Ia is in PGC 2613136, a 17 mag galaxy.  SN is listed as 17.4 mag which would be at peak for the 0.04721 red shift.  It is on the south end of the galaxy with an 18.3 mag star south of it.  If any point is seen at all it will be the SN.  



#3 Redbetter

Redbetter

    Cosmos

  • *****
  • topic starter
  • Posts: 9,215
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 24 July 2020 - 01:11 AM

I gave the three above a try last night in dark sky. 

  • SN 2020oha was headed into a tree with the mirror cooling.  The galaxy was at the edge of detection and I was trying to ID it and another close by to get my bearings.  I wasn't able to nail down the galaxy before the tree claimed it.
  • SN 2020ogn in ESO 597-36 was likely not detected.  Unlike the last time I viewed the galaxy I was not seeing the basic orientation as well.  Seeing wasn't steady enough to get solid hits on a 17 mag stellar point on the edge of the disk.  I had some marginal impression, but that might have just been brightening of the center, never a lock.  I never had an "ahah" moment.
  • I am listing AT2020nxt as seen, although it was marginal.  The galaxy was seen as a faint smudge "ave SB, xf, vvs/xs".  When seeing would sharpen for tenth of a second I was catching a glint W of center of the galaxy, where the SN should be.  Although marginal without ever getting a lock, it was consistent in appearance and location each time it was seen.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics