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Rosette Nebula with the ASI2600MM

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#1 mborland

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Posted 27 February 2021 - 03:15 PM

I very recently received an ASI2600MM and chose the Rosette Nebula as my first subject. This is my first time doing narrowband imaging and I'm quite pleased with the results. I coupled the camera with a SW Esprit 120, APEX ED L reducer, and Antlia 3nm Pro S2, Ha, and O3 filters. Total exposure time for each filter was 3.9 h S2, 1.5 H Halpha, and 1.9h O3, taken over three nights with a nearly full moon. I used 6-minute exposures with a gain of 101 and a temperature of -10C. Everything was processed with PixInsight, with some final noise reduction in NeatImage.

 

RosetteNebula-SHO-2021-02-26s.jpg

A larger version is on my flickr page.

 

Based on this limited experience, I'm very happy with the camera and the filters. My processing needs work to sharpen things up and get rid of the magenta halos around the bright stars. Any suggestions how to do that? I used a star mask and desaturated the stars, making them all white, but that didn't cover the fringes of larger stars..

 

--Michael


Edited by mborland, 27 February 2021 - 03:16 PM.

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#2 SilverLitz

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Posted 27 February 2021 - 03:23 PM

Magenta stars is a normal SHO result.  Try (PixInsight): Invert, SCNR, Invert.


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#3 Stellar1

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Posted 27 February 2021 - 03:40 PM

A beautiful image, colors are just amazing!


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#4 ntph

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Posted 27 February 2021 - 03:46 PM

NIce image; congratulations! 

 

I don't do true narrowband imaging (? yetconfused1.gif shocked.gif ) but I came across something that might help. I was watching David Ault's presentation on Advanced Pixel Math Operations and there is a section on magenta star reduction. 

 

https://www.youtube....v=odjGnqefwHc  

 

The part on magenta stars starts around 36:30 or so. 

 

Hope this helps.


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#5 fallenstarseven

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Posted 27 February 2021 - 03:50 PM

Love the image, thanks for sharing


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#6 mborland

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Posted 27 February 2021 - 04:00 PM

Magenta stars is a normal SHO result.  Try (PixInsight): Invert, SCNR, Invert.

Awesome! That really works!

 

Thanks--Michael


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#7 jmarin

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Posted 27 February 2021 - 07:58 PM

Fantastic image. How do you like the APEX on your Esprit? I have just received my 2600MM Pro and have a Esprit 100, also waiting on Antlia Pro filters to arrive. I've been interested in this reducer but have a bit of analysis paralysis, not sure if it would cover an APS-C sensor well (some here seem to think it's a stretch at this size). Did you crop this image much?. I can't wait to put the rig together, this seems like it's going to be a great camera.



#8 mborland

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Posted 27 February 2021 - 11:44 PM

Fantastic image. How do you like the APEX on your Esprit? I have just received my 2600MM Pro and have a Esprit 100, also waiting on Antlia Pro filters to arrive. I've been interested in this reducer but have a bit of analysis paralysis, not sure if it would cover an APS-C sensor well (some here seem to think it's a stretch at this size). Did you crop this image much?. I can't wait to put the rig together, this seems like it's going to be a great camera.

Thanks!

 

I hardly cropped at all. The APEX seems to cover the ASI2600MM sensor quite well. The star shapes in the corners are not perfect, but they are pretty good (see the flickr version of the image). I probably need to play with the spacing more, but it's good enough for me.

 

--Michael

 



#9 AstronomyFred

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Posted 28 February 2021 - 09:56 AM

Nice result! Thanks for sharing, I think it is a good result, especially for your first try.


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#10 Jim Thommes

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Posted 28 February 2021 - 09:36 PM

Looks good Michael.  Congrats on a number of firsts for you. It always nice to hear these success stories.

 

What I do with narrow band (mostly bicolor Ha OIII) is to process the narrow band data in starless mode. Then add developed RGB stars at the end. Of course, this means that you have to get RGB data for stars, but unless you want extreme depth to the color in your stars, the extra time to gather the RGB data doesn't take that much more camera time. I use pixel math (modified 'screen' formulas) to combine the starless NB and RGB stars images. *DON'T* try to do this with star masks.


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#11 Lonkero

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Posted 01 March 2021 - 09:12 AM

Nice, surprised how the Apex L handles 2600mm, bigger stars look funny tho.For the magenta you can do lot of things, correct magentastars script, colormask script with magenta and with that mask on use curves or ht to bring red down so you get nice blue instead of magenta


Edited by Lonkero, 01 March 2021 - 09:14 AM.

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#12 Simon D.

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Posted 01 March 2021 - 08:34 PM

I’ve never done it, but for your magenta stars, I saw someone use the following technique: invert the image, and magenta will become green. Use whatever tool you have to remove green, desaturate green etc., then invert the image again, and the magenta should be gone. 


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#13 mborland

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Posted 01 March 2021 - 10:52 PM

Looks good Michael.  Congrats on a number of firsts for you. It always nice to hear these success stories.

 

What I do with narrow band (mostly bicolor Ha OIII) is to process the narrow band data in starless mode. Then add developed RGB stars at the end. Of course, this means that you have to get RGB data for stars, but unless you want extreme depth to the color in your stars, the extra time to gather the RGB data doesn't take that much more camera time. I use pixel math (modified 'screen' formulas) to combine the starless NB and RGB stars images. *DON'T* try to do this with star masks.

Thanks for the great ideas. I'll have to invest in RGB filters now, and a bigger filter wheel...

 

Of course, I *did* try making starless images with a star mask and it was terrible! Good to know it wasn't just me.

 

--Michael

 



#14 mborland

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Posted 01 March 2021 - 10:55 PM

Nice, surprised how the Apex L handles 2600mm, bigger stars look funny tho.For the magenta you can do lot of things, correct magentastars script, colormask script with magenta and with that mask on use curves or ht to bring red down so you get nice blue instead of magenta

 

 

I’ve never done it, but for your magenta stars, I saw someone use the following technique: invert the image, and magenta will become green. Use whatever tool you have to remove green, desaturate green etc., then invert the image again, and the magenta should be gone. 

I used the trick SilverLitz described above and it made all the stars white, with no fringes. See the flickr version.

 

--Michael




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