M13 and M57 in astronomical twilight

[Astronomist]

I haven't been able to do any EAA over the summer due to the lack of darkness, so last night I decided to have a quick go at some nice bright targets in the late evening.

This is only my 4th ever EAA session, as I 'discovered' EAA in the late spring this year just as astro darkness was disappearing from our skies. 

Equipment is a manual 10" dob and Altair 585C, M13 is 1457 x 250ms exposures and M57 is ~300 x 410ms exposures.

Looking at the M57 image afterwards I think the exposure was a bit too long as there is some trailing, also I didn't get the colour balance quite right as there is a strong greenish cast to the image. I could post process it away but that would be cheating. 🙃

Edited August 13 by Astronomist

[PeterC65]

Very impressive images. Just shows what's possible without tracking using short exposures but lots of stacked frames.

I agree that the colour balance isn't quite right for M57. You can see that the stars look a bit cyan.

 

[ckp82]

Nice images. I also imaged these on Sunday night although i only used an 80mm telescope. I like how much detail you've managed to pull out of m13. I'd like to try it with my 8" dob but by the time I centre the target manually and switch over to the camera and sort out the focus it'd disapear out of view 😆 Did you find it easy enough to do? 

[Astronomist]

2 hours ago, ckp82 said:

Did you find it easy enough to do? 

The method you describe is more or less exactly how I do it, however I find the 585 sensor is big enough that the target doesn't have time to disappear. It isn't too hard to do as long as your Dob is absolutely silk smooth, although I wouldn't want to use a sensor much smaller than an IMX178. The smaller the sensor is the more time you spend resetting the scope and you get less time to enjoy the view.

Edited August 13 by Astronomist

[ckp82]

11 hours ago, Astronomist said:

It isn't too hard to do as long as your Dob is absolutely silk smooth,

My dob has been gathering dust for a while, I was meant to do the lazy Susan bearing but never got round to it. I got lazy when I started eaa 😆 

[Astronomist]

I succumbed to the urge to post process the M57 image, here it is after running through Siril photometric colour calibration. The colours aren't what I thought it would look like. 

[PeterC65]

The star colours are better but perhaps a little too red. M57 looks very odd! I think you got closer first time around on the night.

I've only captured M57 once, quite a while back with an earlier camera. I must try for it again. Here's what I captured (with an Altair GPCAM2 327C and Skymax 127).

[Astronomist]

I had another session on M57 last night, the colours and SNR are much improved but the seeing was worse... You just can't win.

~1000 x 230ms exposures

if you look carefully to the right and just below the nebula there is the very faintest glimpse of IC1296, a 15th magnitude galaxy. Here's a (badly) post processed crop with the galaxy slightly more visible:

 

 

Edited August 15 by Astronomist

[PeterC65]

That's a much better image I think.

It's nice to spot other objects in the same field of view, especially faint ones which I usually only discover the following day.