Comet C/2020 R4 (Atlas)

[Paul M]

To further hone my talent for trying to image faint comets near a bright Moon, last night I went for comet C/2020 R4 Atlas in CBr . I found it in a washed out sky. Struggling to plate solve due to poor star numbers. No chance of a live stack. I took a few 30 sec subs and in the space of a very short time the comets motion was obvious in the frame. No point running a big batch of subs, the comet would be out of the frame by no. 10.  Couldn't guide on the comet, was struggling to guide on the stars, no chance PHD2 seeing the comet.

Nothing to stack, or to see here in general except the phenomenal motion of the comet. The 250P-DS and ASI178 camera combo deliver a small field size of about 24 x 17 min of arc and the motion between 30 sec subs was east to see on APT preview screen.

Here is a fun little GIF I just put together in Photoshop. I created a simple stretch action to apply each frame as a batch process but there is precious little comet to see.

[Davey-T]

Got something similar the other night but not sure if it's worth the effort of processing.

Dave

[Paul M]

Just now, Davey-T said:

Got something similar the other night but not sure if it's worth the effort of processing.

I know the feeling. I get that about all my data!

When I saw the subs coming in for this I pulled the plug early but decided even then it might just make an animation. 

With a dark sky I might have just been able to guide on the comet. I tried a 9 sec frame rate in PHD2 but still couldn't pick it out.

[wookie1965]

Wow 

[Paul M]

Forgot to mention, this is 12 x 30 sec but there were some breaks while I worked on guiding so this represents 10 minutes of motion between 23:05 and 23:15 

[JeremyS]

Really good vid @Paul M 👍🏻

[bob-c]

Well done Paul.

Bob.

[Paul M]

1 hour ago, bob-c said:

Well done Paul.

Bob.

Thanks!

The forecast is promising tonight so I'm playing with the idea of making a bigger effort on this comet if it pans out. 

It's actually quite close to C/2020 T2 (Palomar) which I grabbed a rough image of a while ago, but not nearly close enough to frame together with my set-up. 

That would have been fun!

 

[Paul M]

I did get out again but conditions were variable, passing cloud slowly taking over.

The comet is much higher now and no Moon! This allowed me to just about guide on the comet to allow longer exposures. Its still ripping across the sky! unfortunately I only got 2 subs at 120 sec due to clouds. Also PHD2 couldnt reacquire the comet after dithering which caused problems. So a bit dissapointed with my 2 Sub stack! not even got the right darks. Anyway:

 

 

I noticed during planning that it was going to make a close pass of a faint galaxy, UGC 8630, and might make a nice animation. i started  run of subs guiding on the stars but as the comet approached the galaxy good old meridian flip came due. Unfortunately forcing an immediate flip in APT is something I'm struggling with and bizzarely even if APT is within a minute of the meridian and you send the mount to the home position in the hope that a goto will send the scope to the east side of the mount it still goes back to the west side and wants to meridfian flip.

That farce meant that i entirely missed the closest approach! I had read up on APT meridian flips but i need to do more study!

I still got plenty of subs and I'll see what I can do in the cold light of day. 

[Paul M]

Trials and tribulations...

Cloud affected my session even more than I thought at the time.

I did capture closest approach to UGC 8630 but the pre meridian subs aren't worth the effort of including in the animation. I applied a simple stretch and curves action to each frame. This is a 95 x 30 sec sub animation.

And this is a quick stack on the stars showing the fuzzies. The comet is the line of fuzz upwards, right of center

[bob-c]

Hi Paul, i managed to image  R4 in the early hours of the 2nd but my sky was poor , also showing  UGC08630. I wasn't sure what it was until i read your post👍,thanks for pointing it out. I use two rigs, ,one for close up with my ODK12.  and the other for a wider field of view a STAR71 pigybacked but i failed to get Palomar in the shot. 

Bob.

[Paul M]

1 hour ago, bob-c said:

and the other for a wider field of view a STAR71 pigybacked but i failed to get Palomar in the shot. 

I abandoned all hope for Palomar. I'd intended to have a try for it after Atlas but it really was hopeless conditions. 

[Paul M]

Just because it's raining and miserable I decided to try and wring a bit more use out of my subs from the other night. This time I stacked on the comet using DSS. Only about 35 of over 100 subs were fit for purpose and they are only 30 sec each. So awash with noise. 

 

[davew]

Hi Paul,

Can I suggest you enter the animation posted on Sunday in the Cosmos in Motion challenge ? 

I keep popping back to look at it and think it stands out as exactly what's wanted in there,

Dave.

 

[Paul M]

32 minutes ago, davew said:

Hi Paul,

Can I suggest you enter the animation posted on Sunday in the Cosmos in Motion challenge ? 

I keep popping back to look at it and think it stands out as exactly what's wanted in there,

Dave.

 

I'm flattered, but I'm not one to put myself on a pedestal. Indeed, I only post my stuff so that absolute greenhorns aren't afraid to post their hard earned offerings because the site is otherwise full of stunning images!

I'm the one you'll find at the back herding the stragglers!