Ursa Major

[squeaky]

Hi all,

This is my first try at using my camera's 18-55 lens and using a time exposure.

My sky is lousy but you can still see a fair bit...

Ursa Major brushing the trees:

Cropped from the above image - Mizar and Alcor centred:

And cropped at full size:

The surprising thing is that faintest stars in there that I'm sure of are mag 9.5...

...though I'm not sure what the bright red dot is.

These are all unprocessed - so it must be time to play... One playtime will be sorting out piggy backing on my scope so that I can track.

Star hopping to M 101:

[todd8137]

Hi there nice first go ,if this was on a camera tripod it's fine,now try take in 10x30secs of ursa major .then put he lens cap on and take 10 x30 secs you can stack hem in dep sky staker it's free,.the dark fames might help with the orange,did you try to removevhevcolor cast?

Great first wide field

[squeaky]

Umm...

It was on a tripod. I wasn't up to setting up my 300P two nights in a row for piggybacking.

I take that "dep sky staker" is "deep sky stacker"?

Yes, a next trial would be to stack a number of shots. Again I think I'd wait until I can piggyback so that aligning will be easier.

I tried tweaking the colour balance but every time I reduced the red "some" the picture turned more green or blue and still looked wrong - just wrong with a different tint. Obviously I've got lots to learn about processing.

Oh, and I'd photo'd in Raw+Fine jpg and those are all from the jpg, so I might well do better when I have a go at the raw file.

Homework for today

[squeaky]

Hokay,

I grabbed the raw file this time and tweaked temperature first and got the histograms showing RGB peaks to line up better, then a little touch on saturation to get them even closer.

Now the trees are green without making the whole image green

And Mizar with Alcor at full size shows that I've lost a little detail (I think) but it's cleaner too.

So... tracked and stacked and I might really get something

I haven't used any noise reduction or sharpening on these. Presumably I'd lose even more detail and would better waiting until I can get a stack?

[jgs001]

Looking good so far. The bright red dot, looks like a hot pixel to me (stack with the kappa sigma stacking, the suggestion is minimum 12, but 10 should be ok) and that will remove the hot pixel.

[squeaky]

What the flying fynn is kappa sigma stacking?

Not that I've got anything to stack yet - it's a bit too bright right now to rush out and grab one

I'll be happy enough to up my stack from 10 to 12 shots. I take it that I'd also need 12 darks?

Edit: I can happily go above twelve if it helps. 15? 20? 25...? I have a 32GB card in the camera so there's plenty of room.

Q1: When shooting should I take a shot then do a dark and repeat until I have my stack, or do all the shots and then all the darks?

Q2: Should I do the temperature and saturation for each photo individually as for my last two posted images BEFORE stacking and processing, or leave them alone and let the stacker deal with them? Or do temp and sat after I have a stacked image if I need to?

Signed: aZillionQuestions'R'us

[jgs001]

Kappa Sigma is one of the stacking options in DSS, you'll see it when you stack them ... sorry.

10 to 12 exposures will be fine, 5 to 10 darks will help, no need to match the number of lights with darks.

Q1, shoot all the lights first, then shoot the darks. You can intersperse if you want, but you risk losing sky time.

Q2, I'd do the processing after stacking, give DSS the raw unedited data.

[squeaky]

And finally(?)

Camera noise reduced and a high pass sharpen done...

A bit tighter on Ursa Major:

[squeaky]

Kappa Sigma is one of the stacking options in DSS, you'll see it when you stack them ... sorry.

10 to 12 exposures will be fine, 5 to 10 darks will help, no need to match the number of lights with darks.

Q1, shoot all the lights first, then shoot the darks. You can intersperse if you want, but you risk losing sky time.

Q2, I'd do the processing after stacking, give DSS the raw unedited data.

OK, will do.