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23 Feb - Supernovae SN2019rz, SN2018hfg, SN2019aik


alanjgreen

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Date: Saturday 23rd Feb. 2230-0005am
Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm & f4.1).
Night Vision: PVS-14 with Photonis 4g INTENS.
Eyepieces: Plossl 55mm (f2 x38), Panoptic 35mm (f3 x60), Panoptic 27mm (f4 x77), DeLite 18.2mm (f5.8 x115).
Moon: 80% (after 2330)

 

After a long wait.
This had been a depressing week as far as stargazing goes. First we had the full moon to spoil the party and then the recurring excitement of “clear weather forecasts failing to materialize” (Thur, Fri and seemingly Saturday too).
After consoling myself by working through the many series of “Prime Suspect” during the week and making regular trips to the window to peep outside “Is it clear yet?”. I was finally taken by surprise last night at 10pm when I saw a CLEAR SKY looking back at me!

 

At least I had a plan prepared!
A couple of days back, I had done some research on http://www.rochesterastronomy.org/supernova and identified six potential supernovae to target (when the moon was not there!). I had setup an “observing list in Sky Safari 5” and had make sketches of star positions from images where available. It seemed that most of my targets have not yet been imaged but Rochester gives the distances from the galaxy core so I could see they were all “close-in”. As my dob uses Nexus push-to then it’s a simple job to nudge over to the galaxy target once 2-star alignment has been completed!

 

Let the supernovae hunt begin...

UGC3554/SN2019rz/Type IIn/Stated mag 16.5
Located 0.6”W and 0.1”N and one image available (Thanks Cedric!).
I was not sure whether I would still be able to get the dob onto this most westerly of my target list (due to the time and dob location in the shed) but luckily it was still available to me!
I started with the 35mm Panoptic (x60 magnification) and the galaxy disk was easily seen and centred in the fov. I could see a clear dot in the galaxy haze. I tried more magnification with the DeLite 18.2 but the view was not as sharp as seen with less magnification (The sky was very “wet” last night and the scope was damp after only 20 minutes outside!). I then moved to the Panoptic 27mm (x77) and got the best view of the galaxy and tiny bright dot centred within.

 

UGC4642/SN2018hfg/Type IIn/ Stated mag 16.5
I tried 35mm, 27mm 18.2mm and 55mm eyepieces. They all showed the galaxy disk and a central dot. Surprisingly the 55mm showed a double dot within the tiny galaxy (one of the dots is the SN). The 27mm provided a better scale for the galaxy and with time at the eyepiece, the double dot came in and out of view.

 

NGC3304/SN2019aik/Type 1a/Stated may 15.9
NGC3304 appeared as a very tiny galaxy in the 55mm Plossl, I was distracted by a much larger galaxy just outside the fov (NGC3294 – which showed clear structure and I noted it for a return visit). As I nudged right the tiny NGC3304 was just discernible and showed a bright central dot.
I switched to the 27mm Panoptic and the galaxy was much larger and easier to see and centre in the eyepiece. The bright central dot stood out within. I could not separate the core from the SN in this tiny galaxy so we need to try again.

 

My other three targets had not yet reached points in the sky where I could get the big dob pointing at them, so that was that for my supernova search for tonight.

 

Let’s see what traditional higher power observing can do?
I removed the NVD and eyepiece and switched to the Ethos10 (x200) only. I settled at the eyepiece and started to make out the galaxy in the fov. The FOV felt huge compared to the 40 degrees of the NVD but the galaxy was more of a challenge to grab with my eyeball. It was certainly larger in this fov but was so much fainter that I struggled to hold it in my vision.
I nudged back to UGC4642 and attempted to see SN2018hfg with the ethos10. The experience was similar again with the galaxy now much fainter than with Night Vision and much more of a challenge to see anything within the galaxy disk.
Of course, the sky was wet (as stated earlier) and by now the Devils Orb was brightening the sky too, so I will make the same attempt and comparison again in the coming week of darker skies.

 

Thoughts of the observer.

  • It’s amazing what you can see with the 55mm Plossl (and night vision) at only x38 magnification. You assume that more magnification is better but with NV the faster focal ratio of the 55mm Plossl (when used a-focally is key). These tiny galaxies are very faint but they are just obvious when viewed with NV.
  • Supernovae hunting is proving that the extra magnification of the 18.2 DeLite and 27mm Panoptic are useful tools too, sometimes you just need the extra scale to reveal fainter stars that are just not seen in the 55mm Plossl.
  • This is the first time, I have gone after SN before images are available so it was intriguing to see if I could spot them “first”! Of course, close in to the core SN are hopefully more easy to discern and further out SN would surely need the star chart sketch to confirm if you see them or not?
  • It is also clear that Galaxies are greatly improved with Night Vision (mostly – there are exceptions where the core seems too large and over powers the disk or the galaxy does not give off enough red for the NV to improve the view or the galaxy is just too large and spreadout over the fov) they are much easier to pick out and most bright galaxies reveal details in the disks that are a joy to see. Generally, I have been surprised at the quality and detail of the galaxy views on offer so far this galaxy season plus those beyond reach previously that are now “in play” too.
  • NGC3294 was a surprise to me, it is not in my “brightest galaxy list” but it was large and detailed in the 35mm Panoptic (I have now added it to my “Brightest Galaxy observing list” to ensure future revisits when the moon is gone).

 

Lets hope we get more clear sky over the next 2 weeks when galaxies will be our main focus of attention and before the Orb waxes once more!

 

Clear Skies,
Alan

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