NGC 1097 from the 'burbs

[DiscoDuck (Paul)]

Originally Posted by alpal

Of course - I forgot that it was nearly 47 hours of data.
OK then - maybe just the stacked FITS files for LRGB
already stacked and aligned &
the LRGB flats stacked results &
the dark frame stacked results for 60s & 180s.

That would be 10 FITS files if Paul was kind enough?

cheers
Allan.

I can have a look when I get home. But you shouldn't need darks and flats if I give you the stacked lrgb images.

[alpal]

Originally Posted by DiscoDuck

I can have a look when I get home. But you shouldn't need darks and flats if I give you the stacked lrgb images.

Hi Paul - that's correct - I was just interested

in what they looked like:
the noise level of the dark frames,
the illumination of the camera sensor.



cheers
Allan

[DiscoDuck (Paul)]

Originally Posted by alpal

Hi Paul - that's correct - I was just interested

in what they looked like:
the noise level of the dark frames,
the illumination of the camera sensor.



cheers
Allan

Allan (and anyone else who is interested). I've stuck some images here:
https://drive.google.com/drive/folde...la?usp=sharing
(actually, they're busy uploading as I type - since I'm on cable my upload speed is sloooow! )



They are LRGB masters, LRGB flats and 60 and 180s darks (all the final stacked masters). The calibration frames are just FYI as the LRGB data is already corrected and stacked.


Note that the RGB masters are cropped (aligned to a cropped partly-processed version of the L master) and so are not the same geometry as the L master.


Also note that, as I said, this was an experiment to see what a lot of bad data could do. As such, I think it is essentially bad data - partly because some of it was captured at poor FWHM, but also because, as Mike and Lee suggested, there's more "work" needed on such data regardless of the theoretical SNR.



I've still to do another L stack with just the good data to get better resolution in the centre, as Colin suggested. I might put that up too when it's done.


Have fun ... and if you get a good result, please let me see (and let me know what you did to get it!).


Thanks,
Paul

[alpal]

Thanks Paul,
I've downloaded the LRGB stacks to make a start on it.
I've already managed to prevent the burn out at the center of the galaxy
by using only an RGB stack before it received its main stretching in Photoshop and a blurred layer mask.
I already pre-stretched them in NASA KITS liberator with function x^(1/5).
This will be a matter of learning what's needed for this image.
It already needed some gradient removal in Fiswork4.
Do you want us to show you only privately with a link if we think we've done well?



cheers
Allan

[DiscoDuck (Paul)]

Originally Posted by alpal

Do you want us to show you only privately with a link if we think we've done well?

Either way is good with me Allan.

[alpal]

Originally Posted by DiscoDuck

Either way is good with me Allan.

Hi Paul,
I need to work more on this image.
Here is a low res sample.
I certainly managed to get rid of the blotchy background -
I think it was the way you stretched it that caused most of that blotchyness -
but I also added noise to finish the background off & get it smooth -

but I don't have anywhere near the galaxy detail that you have.


cheers
Allan

[DiscoDuck (Paul)]

I redid the version on Astrobin with the background done as Allan suggested and the centre of the galaxy redone with only the best subs (as Colin suggested) to give more detail.


I still think it's not very good data/bad processing ... but better than it was.


I think in future I might try longer subs as it seems that the fixed pattern noise and/or the fixed (ie was random but now frozen) noise of the master dark (which is only about 300 subs i.e. 5 hours) presents a baseline you can't stack better than, of course. Hence increasing the signal via longer exposures might work. Another experiment to try

[alpal]

Originally Posted by DiscoDuck

I redid the version on Astrobin with the background done as Allan suggested and the centre of the galaxy redone with only the best subs (as Colin suggested) to give more detail.


I still think it's not very good data/bad processing ... but better than it was.


I think in future I might try longer subs as it seems that the fixed pattern noise and/or the fixed (ie was random but now frozen) noise of the master dark (which is only about 300 subs i.e. 5 hours) presents a baseline you can't stack better than, of course. Hence increasing the signal via longer exposures might work. Another experiment to try

Hi Paul,
yes as per your latest version:

https://www.astrobin.com/full/wvjbti/J/
you certainly got rid of most of that blotchy noise.
It's looking a lot better.
It might not be possible to get such faint galaxy arms showing well
from a light polluted location.
We all need to have our telescopes on a dark mountain in Chile
http://www.chart32.de/index.php/recent


cheers
Allan

[DiscoDuck (Paul)]

Originally Posted by alpal

Hi Paul,
yes as per your latest version:

https://www.astrobin.com/full/wvjbti/J/
you certainly got rid of most of that blotchy noise.
It's looking a lot better.
It might not be possible to get such faint galaxy arms showing well
from a light polluted location.
We all need to have our telescopes on a dark mountain in Chile
http://www.chart32.de/index.php/recent


cheers
Allan

Thanks Allan.

[codemonkey (Lee)]

The new version on Astrobin looks much better! Well done.

[DiscoDuck (Paul)]

Originally Posted by codemonkey

The new version on Astrobin looks much better! Well done.

Thanks