8 Mar - Big Dob tries a Six Supernova marathon

[alanjgreen]

Date: Thursday 8^th March 2018 2150-0210am        Scope: 20” f3.6 Lukehurst Dob with Paracorr (fl = 2089mm)

 

Waiting for a Sign!

Signs were that I may get out for a session (after a two week barren spell). Skies were cloudy at 8pm and the cat came in a little on the damp side so I was a little disheartened.

I got up and looked outside at 9-30pm and the sky was clearing so I started to get ready…

 

Not a Good Start  

Once setup and aligned, I decided to start with some comets. Using Sky Safari I found three well placed comets overhead:

      C/2015 O1 PANSTARRS

      C/2010 U3 Boattini

      74P/Smirnova-Chernykh

I failed to locate any of them and so that was a depressing start.

 

Time for a Nebula!

I switched to planetary nebulas. Fitted the O3 filter and headed for the Eskimo in Gemini. Using both the Ethos6 (x348) and Ethos8 (x250) I could see the central star surrounded by a bright circular disk which was itself embedded in a dusty halo. The circle was bright with the E6 but harder with the E8.

I headed over to the Medusa and was surprised by its size. I ended up with the Ethos13 (x150) where I could see the large curved leading edge. The actual finer detail was hard to tease out and I tried both the O3 and UHC to try to see more. I found the UHC best but this was a difficult target and I felt like I had not seen as much as I should have?

Now onto the Owl. E13 unfiltered. A nice circular cloud was seen with the two big black eyes coming & going from view. I tried the UHC and it improved but I have seen it better.

 

Six Supernova Anyone?

Having spent some of my spare time (in the last two weeks) setting up a “supernova” observing list in Sky Safari. I asked the app to highlight my list and was presented with a clear galaxy hopping trail ready to be explored…

I also made pre-prepared sketches of the SN galaxies and surrounding star patterns so I have something to refer to as I try to orientate myself with the sky region.

NGC3158 & SN2018aaz – After checking my sketch, I quickly had the galaxy centred in the E8. It was a nice size but I could not see the three close in dots from my sketch. Switching to the E6 (x348) revealed more of the smaller stars and I matched the star pattern. Inside the galaxy halo I could see two dots. One of these could have been the SN?

UGC5049 & SN2018pc – At my first attempt last month, I got this SN easily with the galaxy showing easily on that night. Two further attempts had failed to reveal even the edge-on galaxy! Tonight I could see the galaxy and sure enough there was the SN tucked nicely into the centre. SUCCESS  

NGC2746 & SN2018iq – With the E8 loaded, I quickly located the galaxy next to a star. There was no sign of the SN until I swapped in the E6. SUCCESS

NGC3367 & SN2018kp – I have had a couple of goes at this SN already with no success. My shed wall was obscuring my view on those occasions but tonight I seemed to drop lucky and I could get a good view of it. I tried with E6, E8 & E10 eyepieces. The star pattern was easily matched and I had learned a lot from my previous attempts too. I think I finally did glimpse the SN but it was only brief glimpses of a “second dot” in the right place within the galaxy halo. The halo was showing particularly well last night (maybe the extra magnification of the E6?). SUCCESS  

NGC3384 & SN2018yn – I quickly located the host galaxy and then discovered that I had not made a sketch of what to look for! I made a star chart of what I could see ready for verification this morning instead. The galaxy was a good size and showed a nice halo. I managed to see a dot within the halo. Looking at the images this morning it seems more likely that I saw the core than the SN as the core is much brighter on the images.

NGC3941 & SN2018pv – Onto the brightest of them all. I have seen the SN several times already and I must say that it was very hard to split it from the core last night (harder than on previous visits). Even with the E6, the centre looked more like a dual core. A “clear gap” was not seen. SUCCESS (almost)

Oh well, four from six ain't too bad.

 

Worthy of a Mention

I spent the rest of my session taking in galaxies from Ursa Major down to Leo. Some targets worthy of a mention were...

NGC3163+3159+3161+3150+3151 – Five galaxies in the FOV. All of them pretty easy to see. A group of three and a group of two. Ethos8 (x250). A very nice vista.

NGC5350+5353+5354+5355+5358 – Another five galaxy view! This view had the bonus that two of them were interacting with each other. Great!

M87+4478+4476 – A nice “curvy” trio of bright galaxies.

 

Forever the Optimist

Lets hope for a few more clear nights as the new moon approaches!

Alan

[Mark at Beaufort]

Another enjoyable read Alan. I have always felt that planning and preparation makes for a better observing session. Grabbing that many SNs proves the quality of the Dob.

[Demonperformer]

Very interesting read, but, no, I am not going to buy a 50cm dob no matter how good they are

[Littleguy80]

Ace report, Alan. I had a go at the supernova in NGC3941 this week without success. I didn't push the magnification up as high as you though. Without using a barlow, my maximum magnification is 240x so I'll give that a go. Do you think any of the supernovas are achievable at that magnification?

[25585]

Prime gear, the Nexus repaying well. It must be quite a steady, accurate set-up, to keep with such high magnificatons and small FOVs.

[cloudsweeper]

Excellent, Alan.  And I like the idea of gauging weather by the state of the cat!

Doug.

[Demonperformer]

1 hour ago, cloudsweeper said:

I like the idea of gauging weather by the state of the cat!

Yes. To decide if it is raining, pick up the cat and throw it outside, does it bring water back in? Oh, I forgot the hard bit ... catch the cat.

[alanjgreen]

6 hours ago, Littleguy80 said:

Ace report, Alan. I had a go at the supernova in NGC3941 this week without success. I didn't push the magnification up as high as you though. Without using a barlow, my maximum magnification is 240x so I'll give that a go. Do you think any of the supernovas are achievable at that magnification?

For 3941, you only need x100 to find the galaxy. You need min x200 to split the SN from the core. Last night was poor seeing and it was very hard to split them even at x348!

But SN do come in bright and easy occasionally, there was one in m82 a few years back and you only needed x50 or so to see it easily (it was big).

When we finally get one in the Milky Way then it will make a second sun for a couple of months (even visible during the daytime!)

Just spare a thought for any civilisation within 30 light years of the explosion as they became extinct on that day  (at least our sun is in a quiet location).

 

Anyway, keep your eye on the SN website which is updated daily...

http://www.rochesterastronomy.org/supernova.html

SN are listed in brightness order. If you click on the name then it jumps to details of the host galaxy and any images available (sometimes on a sub-page if there are many images). I usually use sky safari to see the galaxy location and then make a list of any that I am interested in. Note that many SN are in the southern sky and cannot be seen from uk (check the coordinates listed).

I also like to choose those where the SN is not too far away from the core or near some star pattern that you may have a chance to recognise.

If you make quick simple sketches of the key recognisable star patterns onto paper then you have something to take outside to refer to that may help locate the exact light source you are looking for (otherwise you will not know the difference with any field star!) 

Also note that the visual orientation of the view in your scope may not match the orientation of the images so a sketch is useful. 

Alan

[Littleguy80]

Thanks for the info, Alan. Super helpful!! I’ll give 3941 another run at 200x and 240x. 

[scarp15]

Interesting account again Alan, informative in terms of the supernova's. Can only offer comment on Medusa, which I had observed on one occasion with 14" dob, dark sky. Large as you indicate, of low surface brightness, as I recall averted vision helped to observe vaguely the profile against the sky background, think I'd used an OIII. 

[alanjgreen]

2 hours ago, scarp15 said:

Interesting account again Alan, informative in terms of the supernova's. Can only offer comment on Medusa, which I had observed on one occasion with 14" dob, dark sky. Large as you indicate, of low surface brightness, as I recall averted vision helped to observe vaguely the profile against the sky background, think I'd used an OIII. 

At least my account is consistent with my previous observation on the Frozen Sixties Night 

Unfortunately, I did not remember my previous account (it was a month ago)

[25585]

8 hours ago, cloudsweeper said:

Excellent, Alan.  And I like the idea of gauging weather by the state of the cat!

Doug.

You can fit a dew shield on a cat. Sometimes known as a Buster Collar. They don't stay on long though ?

[Eastman]

Wow... SN in another Galaxy.

Great report!

I guess 8" won't do the job.