A night of firsts

[Bonamy]

Having spent the previous day screw driver in hand removing the IR filter in my Canon 60D, the skies kindly cleared for me on Friday night. So I decided to see if I could capture the Horse Head.

Camera: Canon 60D
Mount: Skywatcher Adventurer
Lens: Canon 100-400mm at 400mm f5.6
ISO: 1600
Subs: 53 x 60s
Darks: 30
Flats: 30
Bortle Class: 4

Stacked in Deepsky Stacker (100% of lights, I had removed 15 subs due to various issues), processed in Photoshop

The moon was not ideal, but I'm still getting used to the whole process, so making use of the early enthusiasm and getting some practise in.

I tried a number of different processing techniques, and decided this version had the best balance, although I realise I may have overdone he noise reduction (it was significant at this stretch).

I'd welcome some feedback, and also suggestions on what to look at next. I have a clip in H-Alpha filter ordered, so I was thinking I might have another go with that (esp with the moon getting brighter).

However, my view to the west isn't great, and Orion is getting low, so limited on exposure time)
 

[PeterCPC]

Great image. You might want to concentrate a bit more on getting the focus spot on. Not easy with a zoom lens.

[Bonamy]

6 minutes ago, PeterCPC said:

Great image. You might want to concentrate a bit more on getting the focus spot on. Not easy with a zoom lens.

Thank you. I did use a bahtinov, but will double check. Also, I had tape with me to tape down the focus ring, but forgot to use it. I suspect the poor focus might have been exaggerated a bit by the noise removal. The DSS output looks much sharper.

Thanks for feedback

[rickwayne]

It does have that "plastic" look common when you lean too hard on NR. It would not take much focus  or zoom creep to soften things either  -- you can  check by loading subs from the beginning and end as layers in Photoshop, auto-aligning them, and playing with the opacity of the top one to blink-compare them.

Two  things about using a Bahtinov mask: You have to be super-exacting if you're shooting at low f-ratios, and even if you nail the focus to start, thermal effects can throw it off as the night progresses. For my 336mm f/5.5 rig, the critical focus zone is all of 74 microns deep and 1 degree C is enough to bollix the focus.

I personally don't mind a bit of noise in an image showing good detail, though I do tend to pull that slider a little too enthusiastically. Of course, I was a late-70s photojournalism major so I perforce learned to tolerate a lot of grain.

Obviously a nice job with polar alignment, BTW. Pixel-peeping reveals a bit of elongation in the RA axis but I don't see any in DEC (RA is vertical to the  Horse and DEC along its base), so not a lot of drift going on there.

Edited March 21, 2021 by rickwayne

[Bonamy]

Thank you for the tips Rick, I'll have a look at the subs as you suggest, and will check regularly from now on.

PS Thanks for the new term "Pixel-peeking".