Someone please guide me!!!!

[rockinrome]

OK, so this is going to be a post where I do not expect an answer but rather - have you tried this, and I go, no I haven't and it works perfectly .... so no pressure you lot!!!

Here we go .......
I have been getting reasonable images lately using my unmodded Canon 600D with SkyTech CLS clip-in. I have the Rowan modded HEQ5PRO which I ASCOM guide through an Orion off-axis guider (that is another story ....!!!!) - This works great.

The other night I took 2 hours of data [4min subs at ISO800] of the Pelican Nebula (IC5070), with darks, bias and flats (all as usual).

I stick it through Deep Sky Stacker and no matter what I do I cannot get a decent pre-processed image to put (say) into PhotoShop.

I do struggle with this part but usually manage to get something decent (normally with much less data too!)

One thing to note would be .... whilst taking the images I just had a peak at what was coming off the camera and you can definately see the Nebula in 1 frame quite easily.

I will thank you in advance and have a great weekend.
Clear skies.
MJ
 

[david_taurus83]

Could you post up the file that DSS has produced? And a single sub and a single flat?

[happy-kat]

I personally do not do pre processing, the fits file I take straight into StarTools to process.

[rockinrome]

32 minutes ago, david_taurus83 said:

Could you post up the file that DSS has produced? And a single sub and a single flat?

Hello David
I do not have the DSS file (at work), but do have a sub and flat - in attached zip file.

Thank you

MJ1.zip

[david_taurus83]

When you say pre processed in DSS do you mean you adjust with the sliders before saving?

[teoria_del_big_bang]

I am no expert in this, far from it and with the processing side on the lower part of a steep learning curve. But you mention you have peeked at one sub and there was definitely something there, have you looked at them all before pre processing? I think it is important to weed out any bad images before doing any stacking as the bad ones can just obliterate all the detail on other perfectly good frames. Idealy you need to temporarily stretch the images to determine which are good and which are bad and I think a final processed image with only a few good frames is far better than one with lots of frames some of which are dubious. I guess if you know all session the skies were clear it helps but often clouds pass and are only on some frames. Just a thought.

Steve

[rockinrome]

1 minute ago, david_taurus83 said:

When you say pre processed in DSS do you mean you adjust with the sliders before saving?

I tried both - so saving with changes (which brought out the Pelican slightly) and no changes to try and sort in PhotoShop.

MJ

[rockinrome]

1 minute ago, teoria_del_big_bang said:

I am no expert in this, far from it and with the processing side on the lower part of a steep learning curve. But you mention you have peeked at one sub and there was definitely something there, have you looked at them all before pre processing? I think it is important to weed out any bad images before doing any stacking as the bad ones can just obliterate all the detail on other perfectly good frames. Idealy you need to temporarily stretch the images to determine which are good and which are bad and I think a final processed image with only a few good frames is far better than one with lots of frames some of which are dubious. I guess if you know all session the skies were clear it helps but often clouds pass and are only on some frames. Just a thought.

Steve

Thanks Steve, now then, you could be onto something here......
I did check a sample of the images, BUT there was some high cloud around at certain times all night which I thought I had avoided as it drifted..... may be that is the culprit ......

MJ

[teoria_del_big_bang]

Also when you have weeded out any bad frames you could try running them through DSS without the calibration frames just as a test. You may get a noisy image with dust bunnies and so on but it will give you a quick idea what you have captured and then when you try again with the dark frames ets you should see improvements in the image, if not then maybe some issues with the one of the calibration frames.

Steve

[david_taurus83]

12 minutes ago, rockinrome said:

Hello David
I do not have the DSS file (at work), but do have a sub and flat - in attached zip file.

Thank you

MJ1.zip 39.67 MB · 0 downloads

Could do with the DSS stack and stretched to see what kind of issues your having. The reason I asked for single sub is to see if the stretched issue is seen in the sub. And how your flats look as they can either work out great if done properly or cause all sorts of weird gradients in the stack.

[rockinrome]

5 minutes ago, david_taurus83 said:

Could do with the DSS stack and stretched to see what kind of issues your having. The reason I asked for single sub is to see if the stretched issue is seen in the sub. And how your flats look as they can either work out great if done properly or cause all sorts of weird gradients in the stack.

Ahhh right .... gotcha ..... I will upload when I get home then. Thank you.

[rockinrome]

13 minutes ago, teoria_del_big_bang said:

Also when you have weeded out any bad frames you could try running them through DSS without the calibration frames just as a test. You may get a noisy image with dust bunnies and so on but it will give you a quick idea what you have captured and then when you try again with the dark frames ets you should see improvements in the image, if not then maybe some issues with the one of the calibration frames.

Steve

Sounds like a good idea. Thanks again.

[carastro]

Awaiting stacked file, though if there are some dodgy subs, it might be better to gives us all the subs and calibration files so we can wheedle out the bad ones ourselves.

Carole 

[rockinrome]

6 minutes ago, carastro said:

Awaiting stacked file, though if there are some dodgy subs, it might be better to gives us all the subs and calibration files so we can wheedle out the bad ones ourselves.

Carole 

Hi Carole

I will check the subs first I think - don't wanna give you all crap data from the outset!!

Thank you
MJ

 

[happy-kat]

The point of registering all files first in DSS is you can then use the scores and other data to select and wheedle out the poor images before stacking.

[rockinrome]

So, just checked my light subs - I may have found the culprit, but need opinion ....
It's that massive great lump of rock in the sky that reflects sunlight back to Earth *I think* ...

As I scroll through the 30 images they become lighter and lighter. I do not detect any cloud in the frames although some later images appear more noisey than others.

Thoughts?

Thanks, MJ

[happy-kat]

It's worth looking at the scores anyway I think

[carastro]

Sounds like it might be the reason.  I'd do several stacks, first batch that have come out OK, then keep adding a couple of subs until it looks like it's deteriorating.  Bit of a pain, or do what Happy Kat has suggested, though I never used that method in DSS myself, but I have seen it done by an astro chum who's a bit more techie than me. 

Carole 

Edited September 20, 2019 by carastro

[rockinrome]

Thank you all for the input. It's funny how talking about a problem takes you down roads which you don't think of as an individual.
Anyway. I took the first sub and streeeeeeeeeeeetched it to hell in GIMP to be quick and dirty and there is loads of data in there (see attachment).
Bloody Moon!!!!!

Thanks again and clear (moon less) skies ...
MJ