8 replies to this topic

[unimatrix0]

I know this target is not the best one for wide field with low focal length (572mm) and I do have a mono setup I can go at this at will (533mm pro) , but lately I enjoy simpler processing of OSC camera images instead of mono LRGB. 

 

I used my Newtonian (150mm) and Sharpstar coma corrector

 

Nikon D5600 (full spectrum mod) -  ISO800- 60 second subs,  +  used special flats- exposed lower than mid histogram

 

There were some color rings after stretching anyway, so I went ahead and using Pixinsight's  light mask creation and using the noise reduction process ACDNR, which will get rid of chromatic noise (color),  I adjusted hard to neutralize the background and remove most of the color rings. 

 

Since I'm developing my own teqhnice to get rid of the concentric circles (chromatic noise reduction, background neutralization etc) , plus using ISO800 doesn't seem to help with the ring problem, i might try lower ISO settings again. 

 

So far I'm happy that I still didn't spend $1400 for a cooled APS-C size camera 

 

Image is probably worse now since I saved it a a .jpeg and uploaded it to this forum gallery, but anyway. It can be done. 

 

edit: there is a noticeable star elongation, yesterday morning I realized that my Newtonian is still not well collimated, plus at APS-C sensor size, coma correcting may not get a whole lot better anyway. 

 

I didn't use any blur exterminator or noise exterminator either. 

 

 

 

Edited by unimatrix0, 27 February 2024 - 02:12 PM.

[deSitter]

I know this target is not the best one for wide field with low focal length (572mm) and I do have a mono setup I can go at this at will (533mm pro) , but lately I enjoy simpler processing of OSC camera images instead of mono LRGB. 

 

I used my Newtonian (150mm) and Sharpstar coma corrector

 

Nikon D5600 (full spectrum mod) -  ISO800- 60 second subs,  +  used special flats- exposed lower than mid histogram

 

There were some color rings after stretching anyway, so I went ahead and using Pixinsight's  light mask creation and using the noise reduction process ACDNR, which will get rid of chromatic noise (color),  I adjusted hard to neutralize the background and remove most of the color rings. 

 

Since I'm developing my own teqhnice to get rid of the concentric circles (chromatic noise reduction, background neutralization etc) , plus using ISO800 doesn't seem to help with the ring problem, i might try lower ISO settings again. 

 

So far I'm happy that I still didn't spend $1400 for a cooled APS-C size camera 

 

Image is probably worse now since I saved it a a .jpeg and uploaded it to this forum gallery, but anyway. It can be done. 

 

edit: there is a noticeable star elongation, yesterday morning I realized that my Newtonian is still not well collimated, plus at APS-C sensor size, coma correcting may not get a whole lot better anyway. 

 

I didn't use any blur exterminator or noise exterminator either. 

 

 

 

Nice! You also got a good capture of NGC 3077, which is one of the strangest galaxies out there.

 

-drl

[unimatrix0]

Nice! You also got a good capture of NGC 3077, which is one of the strangest galaxies out there.

 

-drl

Yeah I saw it on the framing that there are some smaller galaxies around and tried to get it in there, although I didn't know 3077 was strange. 

[MarMax]

It's interesting that you don't see Holmberg IX with a four hour integration. The double star TYC 4383-860-1 (Stellarium) is clearly visible and I would expect a hint of Holmberg IX.

[deSitter]

Yeah I saw it on the framing that there are some smaller galaxies around and tried to get it in there, although I didn't know 3077 was strange. 

It was one of Karl Seyfert's original list of active galaxies with bright central condensations. It has a sort of morphological companion, NGC 1275 in Perseus, another extremely odd duck that has redshift data which strains the usual explanation to the breaking point.

 

-drl

[deSitter]

This is just a beautiful capture and framing of the galaxy but it seemed to need a little more contrast, at least the forum version. My apologies, I just used a primitive program and adjusted the brightness and contrast until the outer regions began to disappear, then backed off a little.

 

-drl

Attached Thumbnails

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[deSitter]

BTW this region is just criss-crossed by gas and matter not associated with specific galaxies. Check this out.

 

https://www.astrobin.com/7ez0pl/

 

-drl

[deSitter]

BTW I noticed that my Nikon D5100 using the default settings makes terrestrial photos that I would consider a bit low in contrast. My Coolpix S9700 does not. I have not got around to investigating it thoroughly.

 

-drl

[EPinNC]

Nice image!  Always an enjoyable pair to see.

 

It's very similar to my effort on it so far:

 

 

(a very downsampled jpg)

 

Bortle 7

AT102ED refractor (f/7)

Nikon D5600 (unmodified)

418 x 30s (~3.5 h)

ISO 200

Processed in Siril, RawTherapee, and GIMP

 

I'm hoping to get a couple more hours on it when skies clear up again.  It's still a bit noisy and getting those faint wispy outer arms on M81 is tough.  Pulling color out of it is difficult for me.  Obviously I'm not going to get the H-alpha streamers on M82 with my unmodded camera, but that's life.

 

Keep on shooting!  (Until you're ready to move on, of course)

Edited by EPinNC, 29 February 2024 - 08:45 AM.