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Ceph and Cass

Advice please...and an image to try your best!


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Hi all,

It's been a while since I have actually done any dslr imaging but last night I had go under my new skies and I must say I'm underwhelmed by the results given the fact I can visually faintly see the Milky Way.

So I'm trying to find out where exactly I need to improve or is it just my expectations are too high. The last time around I could faintly see the MW I had no trouble at all capturing it in a simple 30 sec exp, this time no such luck.

Anyhow, I know my processing is not much chop and I can't seem to do anything that I feel improves it out of DSS. See the dropbox link below and please have a crack at it if you like.

We have 32 minutes of stacked 30 second exposures and nearly the same in darks, no flats.

https://www.dropbox.com/sm/create/kk.TIF

Here is a jpeg of the TIF as well.

post-8383-0-35473400-1375184374_thumb.jp

I'll also add a individual 30 second frame if I can but I keep getting "error 503 upload skipped" messages

Details are..

50mm

f/6.3

30 sec exp

ISO 400

WB Manual

So as you can see amongst other things the stars seem blown in the core once stacked, so much so there are little black dots in the center of the brighter stars. This is a new one to me, I haven't had it happen before.

Any ideas folks?

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Had a quick look, possible focus issue causing the donuts around the bright stars or very bad and turbulent seeing?

Just to see what was there I've over stretched the image, used FTS filter and median filter plus maxed out with colour saturation.

Needs proper flats to counter vignetting but you've managed to catch something!

Reprocessed in MAXIM DL

Couldn't log into your other images, password protected site?

William.

Edited by Oddsocks
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Hmm... maybe you need to be a dropbox member to download the image. I didn't think it required that, sorry about that.

And yeah I know I should take flats but I haven't found a reliable way to do it with just the camera lens, maybe a torch and a white shirt? Can't hurt to try.

Seeing was pretty good, not perfect but I have seen worse, focus probably could be better but it only appears after the image is stacked and not on the single subs.

Finally a single sub loaded

post-8383-0-98615800-1375193867_thumb.jp

That's what I mean, it's not astounding and I have had better results with 8 sec subs in more light polluted skies.

I have checked the camera settings and everything is turned off and nothing changed since my last outing.

I'm going to try a different lens or two tonight and maybe reset the cameras factory settings if still no joy.

Edited by JB80
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Hi Jarrod

Really needs an expert to look at this....I took your single sub and stretched / zoomed in Photoshop.

Many of the brightest stars have donuts which looks like focussing, the dimmer stars are showing hints of donuts and oversampling with diffraction rings.

I've attached one of the more prominent donut stars from your single sub.

These only show when extreme stretch is used so you only begin to see them when stacked.

White tee shirt and torch can work for flats or point towards nearby white painted wall or building otherwise sky flat at twilight or dawn is better than nothing.

William.

Edited by Oddsocks
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Thanks guys for taking a look.

I'm putting it down to user error due to rustyness. Like you say focus was out and last night I switched to the nifty fifty, spent time getting focus right and the results are much better. See link below.

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