feverdreamer1

3 hours ago, michael8554 said:

I don't remember the reason, but choosing ISOs that aren't whole-stop increments is not recommended for long exposures.

So use ISO 800 or ISO 1600, I would say 800.

Michael

Oh, didn´t know, will remember it for next time, cheers!

Ill add my final edit too, played with curves and levels, a bit of saturation and crops here and there:

Loads of noise I know, but Im happy with my results.

Again, thanks everyone and Clear Skies!!!

2 hours ago, Malpi12 said:

some further messing in Gimp for you to try  :- construct an artificial flat,
Duplicate the image to a new layer then with with Filters > Blur > Gaussian Blur choose a size in both X and Y which is a large fraction of your image pixel  dimensions
Change its Layer Mode to Subtract then merge down.

Here is a quick first attempt to illustrate possibilities (it is a bit heavy handed !) using size 500 in both X and Y

I have cropped the margins as this method creates edge artifacts where the blur runs out of ststistics.
happy gimping ,,,Im no expert, give it a whirl,,, 

Looks really cool, and will definitely use that method and test it out. Great job given the data. Thanks!!

1 hour ago, steppenwolf said:

Flats are what are really required here but this is what I did in PhotoShop:-

1. Levels

2. Histogram balance

3. Levels

4. AstroFlat plugin (also available for The GIMP)

5. Levels

6. Curves

 

Yes, after this, flats will be a MUST in every session, glad to have learnt the lesson, even in the hard way haha.

Great image, really like the sky color you got.

1 hour ago, Laurieast said:

GradientXterminator  works with that.

Will look into it!

34 minutes ago, ONIKKINEN said:

Hmm, for some reason i did not notice that the original post had a link to the stacked file...

Well, anyway ran it through Siril and some photoshop fiddling afterwards:

Background extraction as a first step to the linear file worked very well and the image is perfectly salvageable. I stretched it a bit too far here, but this is a quick edit that shows you can work with the data without flats in this case, if necessary.

Ive never used Siril, but the image proves I really should, will take everything you said into account and will try to learn Siril and edit it again. Many thanks!!!

19 minutes ago, Aramcheck said:

Likewise - I did a quick & dirty process in Pixinsight. DBE did a fair job of removing the vignetting.

Cheers
Ivor

Yep, image is prefectly salvageable, thanks a million Ivor.

4 minutes ago, malc-c said:

I would assume taking a load of Darks, Flats and Bias images ??

Yes, but the only calibration frames I managed to get were Bias, as my camera died and ended up only taking lights

5 minutes ago, scitmon said:

I presume you know that flats remove vignetting, but are looking for an alternative because you ran out of time to take them?

Yes, exactly.

Alright, have been touching sliders here and then and reached to this:

Looks much better, but theres still that vignetting, will continue messing with it hahaha

Hello,

Went to a trip to a Bortle 3 sky last december, just got time to start processing and all.

Stacking went fine, there were about 34 lights of 2 mins and about 30 bias (couldnt do darks because battery ran out before I could start doing them, no flats either for the same reason.)

The bias were taken the day after.

So, about an hour of exposure of M45 with a canon 550D, 55-250mm at 135mm and ISO 1250.

I thought i had some good data to work with, however, im starting to process it and it looks like it wasnt as good as I´d thought.

Whats really bugging me is this vignetting:

All I´ve done is adjust the black and gray pointers in Levels, but i get this ugly red haha.

Stacked file is:

https://drive.google.com/file/d/1sm-_MVfILDNd9aMexPY5KDnjoepCaOZ8/view?usp=sharing

Thanks in advance and clear skies!

19 hours ago, vlaiv said:

In any case, maybe you should calibrate your data, there are a lot of hot pixels, so at least darks. This is what I was able to pull out (not very versed at processing wide field shots):

All those red dots are hot pixels. Blue halos around stars are chromatic aberration of lens used. There was very strong gradient in the image from light pollution that I needed to remove, so that was done in ImageJ along with x3 bin to improve SNR (but image is now smaller - only ~1500x1000 px because of that). After that I composed back channels in Gimp and did very mild curves adjustment and a bit of denoising.

Maybe I could get better image if you post linear 32bit data, but don't expect great improvement. I think this is good as is.

I would definitely have calibrated it but my camera died on me 😞. 

It's a very nice edit Vlaiv, you really managed to take out that strong LP gradient. I tried quite a lot but I'll have to dabble with it again hahah.

Thanks for all the info and the time you spent on this, I really appreciate this.

Will try to edit again to try and reach something similar to yours.

Thanks again and clear skies!

Here it is:

output.tif

Right @vlaiv, will attach as soon as I reach home, sorry for the trouble.

Hey there, recently went to a dark sky trip last friday and although the imaging session got cut short (due to battery issues...you should make sure they're charged btw😅), had an amazing time under the stars.

Now, I knew I wouldn't get an APOD image, but i was really hoping i got something good, cause the place was quite dark and the tracking was just on point...However, after reaching home and stacking and processing, I don't see as much detail as I was hoping to. I dont know if its because of the quality of the subs or my editing skills, but I cant seem to bring out much of it without completly wrecking it unfortunatey.

So, I am asking if you could try to edit it for yourself and tell me if its the image or my (albeit basic) processing skills.

Processing I do with gimp, so if the methods are aplicable to it too, that'd be really great. Stacking was done with sequator I've heard its better for wide-field, if this is not the case, please do let me know what you use  

Thanks in advance and clear skies!!!

output.tif.pp3

9 minutes ago, vlaiv said:

It is open source and free. It's used for scientific image analysis (mostly microscopy) but it has all the right tools. It's not hard to learn, but most of operations are fairly generic - you need to understand image processing quite well to accomplish what would otherwise be simple "filter" in photoshop or similar.

Hmm I see, will stick to what I'm using for now, and try to "master" that before jumping to other software,

Thanks and have a good one,

S

11 minutes ago, vlaiv said:

Sure. I loaded the Tiff in Gimp 2.10 and then I split channels - red, green and blue into separate monochromatic images and saved them as fits files.

Then I loaded each of them in ImageJ. I binned them 3x3 to improve the SNR and then I did synthetic flat fielding.

I inspect image and find max pixel value that saturates targets but does not saturate background. Then I run macro to remove all the pixels with higher value in the image (this sort of leaves only background). I then run another command that fills in missing pixels by taking average of existing pixels around them (sort of mean filter that only looks at actual pixels and not missing values).

In the end, I do low pass filter with Fourier transform to remove fine detail / noise and leave "smooth" background. I divide each channel with respective background.

Then I run gradient removal plugin that I wrote on each channel and save them all.

I then loaded each channel in Gimp and did channel combine to get RGB image back again and did basic 3 point levels stretch (move top slider until nebulosity is about to saturate - move middle slider to properly expose everything and move bottom slider to remove background offset).

That is it. Most of the work is done in ImageJ - but after flat field is applied and gradient removed - data is really nice to work with.

Thanks Vlaiv, for such a detailed and well explained message. Is imageJ easy to learn? I'm still getting used to GIMP and am now starting to properly use StarTools.

2 minutes ago, vlaiv said:

Well, it is very decent recording

I had to jump thru a lot of hoops to get this level of detail, but I think it is worth it.

Flat calibration was not performed - there is a lot of vignetting and there is also some LP gradient in the image. Quite challenging processing to be honest.

Here is result:

I think that you should be pleased with this - you captured great nebula of orion, running man, horse head and flame in one frame!.

Thanks Vlaiv, that's a great image. I didnt do flats, but I plan on learning how to do them soon. 

May I ask how and where did you process it? Thanks again and clear skies,

S

This is the tiff (16bit/ch) file:

https://drive.google.com/file/d/1sm-_MVfILDNd9aMexPY5KDnjoepCaOZ8/view?usp=sharing

6 minutes ago, vlaiv said:

It is normal to have high background levels if you shoot in light pollution and have faster lens.

This is always dealt with in post processing.

54% is too aggressive setting for Kappa Sigma clip. Set it to reject top 5% or so of samples - sigma of 2 will give you 95% accepted and sigma of 3 will give you 99.7% samples accepted.

Okay, almost thought I had wasted another night. Thanks, I will try what you say.

16 minutes ago, LeeHore7 said:

Try processing it and see what you get, nothing to lose there, great start 👍

Will do for sure, that stacking time won't be wasted  

Some background, as you can see, it's the orion nebula and neighbourhood.

This was shot last night at ISO 1600 canon 550d. With a CZJ 135mm stopped at f3.5 I believe. (first light with this lens by the way). 

There are 58 frames at 50 seconds each, after discarding about 30. I also took 10 bias and only 15 darks because my camera died :(.

Is this image too bright? Should I process it or did I mess up some DSS setting. I used Kappa sigma clipping and abour 54% treshold.

Thanks and clear skies!

By the way, just picked up the Carl Zeiss. 

9 minutes ago, barbulo said:

This is one of those moments of homesickness for my home country 😢. Just compare: 

Oh man. At least I'm sure you'll take full advantage of clear nights.

19 minutes ago, alacant said:

¿Málaga? Looking perfect:

 

Yup, but it said the same yesterday and well... couldn't see polaris at all so couldn't do anything really 

1 hour ago, alacant said:

If that's a Zeiss then you just stuck gold with the 2.8!

The adaptor looks fine to my eyes but take along your camera and check it anyway. If the camea throws a wobbly, just tape over the electrical contacts on the bayonet of the lens.

Here's our mc-s 3.5 focused at infinity.

Good luck:)

 

Awesome. Good to know I'm getting a good deal. Will for sure take my camera dn check if it fits with my uhc clip in. Let's hope it stays clear for tonight 😁😁

11 hours ago, alacant said:

Should do. Got a photo?

If not, a M42 to EOS adapter which will is only around €3.

 

Yup. Uploading right now

Hey @alacant

I found one second hand nearby. It already has a canonaef adaptor. Will it reach to infinity focus?

2 hours ago, alacant said:

There's a Zeiss here:

https://www.ebay.es/itm/Carl-Zeiss-Jena-DDR-135mm-f3-5-MC-S-M42-Lens-/274710705989

And a Takumar here:

https://www.ebay.es/itm/Lens-Asahi-Super-Takumar-135mm-F3-5-M42-Mount-Ref-192034-/164689293847

Loads more by searching the same source.

HTH.

Hmm yeah, normally I search for things that are local/in hand sale, haven't ever bought in ebay. Will check it out though. 

Many thanks,

S