M13 basic test shot

[michael.h.f.wilkinson]

Nice image. When I get back to work, I could have a go with our so-called k-flat filters (article here). They could kill noise without getting rid of stars. Still, there is no substitute for better data

[Quatermass]

Heres one of Eastern Veil I did for Graham today from his .tiff he sent me, needs a bit more work still but has encouraged me to have a crack at myself

[squeaky]

Nice image. When I get back to work, I could have a go with our so-called k-flat filters (article here). They could kill noise without getting rid of stars. Still, there is no substitute for better data

Ooh! By all means have a go at it

Yep - as it says in the tile really, I just wanted to test the basic procedure for getting and processing an easy DSO. Proof of concept, really. This is my first time round at all this so there is much to learn.

Hopefully Monday night will give me a chance to get some good data and then, after a good watch of Mark's tutorials, squeeze the best image I can get out of it

Monday nights looking like it might be a good one I will try to get away providing we don't have baby sitting dutys to attend to fingers crossed and visit you and Chris at the caravan site.

Fingers crossed!

[Steve Ward]

Hi Squeaky ,

Think you may have a stacking issue to start with ! , If you zoom in a bit you have feint duplicate stars all over , just about the 12:00 position

Either that or you've just discovered a million new binaries

Still much nicer than my now discarded orange version.

[squeaky]

Heres one of Eastern Veil I did for Graham today from his .tiff he sent me, needs a bit more work still but has encouraged me to have a crack at myself

Stupendous

[Gina]

The Veil is something I want to have a go at Mind you the weather to have a go at anything would be nice!!!

[Quatermass]

Had another quick go.. agreed Gina soon very soon

And another play..

[Gina]

That's really beautiful Mark

[squeaky]

Hi Squeaky ,

Think you may have a stacking issue to start with ! , If you zoom in a bit you have feint duplicate stars all over , just about the 12:00 position

Either that or you've just discovered a million new binaries

Still much nicer than my now discarded orange version.

Yes, I noticed those. I think they were always there - but the processing needed to keep the genuine faint stars brought those up too. I think it's much more likely to be tracking or "shutter shake" than a stacking issue. Anyway, I'll find out after my next session

You binned the orange?! Go get it back and send it here - there must be a way!

[squeaky]

OK so I checked my images... in DSS I decided to bin everything with a score lower than 100, and I also binned the one that had a score twice as high as any others (so that would be the one with the "echos" in).

DSS then stacked the best 80% (all six of them) and absolutely minimal processing in PSP gave me...

[squeaky]

Right... to sum up...

I started with 15 ten second subs (because of tracking and drift issues) and so used a high ISO (3,200) to grab as much light as I could, even though I knew it would be noisy.

So I got 15 subs the best of which looked something like this...

And my first processing result using defaults in Deep Sky Stacker looked like this:-

After a fun weekend playing around I discovered that "Less is MORE".

Of the fifteen subs I had - quite a few had low scores, so I unchecked those, and then unchecked one that had more than twice as big a score as any other sub - which in some of the intermediate results posted here show a whole bunch of star "echoes".

This left me with just six ten second subs to stack and DSS was set to use the best 80% which meant, in fact that it only stacked FOUR of them.

As you can see - the noise finally caught up with me - but using noise reduction options, or levels and curves to try and get rid of it also lost me some of the fainter stars.

Luckily, Paint Shop Pro has a colour replacer option which instead of working on the whole colour channel (and who's got a grey or magenta channel anyway?) works on individual colours in the palette and has options for tolerance and feathering. So using very gentle levels I hit it three or four times to remove the noise and then did a single "Unsharpen Mask", again gentle, just to make those fainter ones a bit more pinpoint. A final couple of colour replace sweeps to get rid of the last of the noise that the sharpening "lifted" and Robert is your aunty's brother...

Seemples

EDIT: For a bet, not all of this is going to work on galaxies or nebulae... but I think I'll save those for another day

[Steve Ward]

Nicely done sir ,

Lot of faffin' about but well worth the effort.

[Quatermass]

The fun is in the faffin

[Steve Ward]

Must admit I'm beginning to see the light (npi)

I shot some short 20s subs and darks of M57 the other night as an experiment ( same night as my orange M13 !)

Stacked TIFF showed about 10 stars and nothing else.

Had a play with it in WLive PhotoGallery , histogram stretching , saving and then restretching , as well as bright,contrast etc and extensively cropped when out popped my best Ring Nebula to date.

I'm sure you guys could get more out of it , not sure how to get link to it as the Tiff file is too big to post (35.5Mb) and too big to e-mail.

Photobucket won't take it as not jpeg !

I'll see if I can get it onto Flikr.

[Steve Ward]

Can't do it , files too big !

[michael.h.f.wilkinson]

Can't do it , files too big !

Want to try our files for size. The smallest in my current test is 870 megapixels, the largest 3.9 gigapixels

[squeaky]

Hi Steve

Ok, from the tiff you sent me... I don't think that you can do the stars and the nebula all in one go. Since you'd got a nice nebula I created a second layer and worked on those, then plonked your nebula back in... quick and dirty this one... gotta get ready for viewing tonight...

So with a bit of time it could be pretty darn good

EDIT: I think that either your stacking needs a tweak, or you started with VERY faint subs. Take a look at your individual subs and only use the best 50% of them. See what your tiff looks like. Don't be afraid to bin rubbish subs - after all, they'll only add rubbish to your result. My best result for this M13 came, in the end, from just four of fifteen!

[Steve Ward]

They were very feint !

Wasn't til I shoved Brightness right up that i got a glimpse of Ring.

Sky pretty orange at time so going to try again a bit later and add UHC and OIII tonite for comparisons.

Thanks for playing , have fun tonite , looks reasonable here for a change.

Steve.

[squeaky]

Hi all, remember this...?

Finally decided to try my hand with Photoshop...

Subtle difference

Remember that's 40 seconds worth of subs, done on a dob. Anybody want to swap a dob mount for an EQ6?