Camera: QHY163M (16mp mono) CMOS cooled to -15 degrees C.
Telescope: Takahashi FC100DF Steinheil fluorite doublet apochromat refractor @ f/7.4.
Reducer: None.
Mount: Paramount MyT.
Filters: Astrodon 5nm Ha, 3nm O3, 3nm S2.
Software: Sharpcap, PixInsight.
More detail and different versions are here: https://www.astrobin.com/4j0pwf/
I've been meaning to do this target for a long while but removed the reducer on my FC100DF so I could get it to fill the frame a bit better (you can see the consequence of not having a flattener with the corner stars and focus is difficult since my FC100DF doesn't have a microfocusser which I've just finally ordered so I can tighten this part up a bit, which should show up in my next image of the NGC281/Pac Man Nebula). This is the first target I've imaged with the FC100DF at its native focal length and it's also the first target I've managed to finish processing since last fall.
The Wizard emission nebula is a relatively bright and popular target for astrophotographers. The star forming region was discovered as an open cluster (Cr452/NGC7380) in the constellation Cepheus by Caroline Herschel, whose husband included it in his catalogue. The large active region has a radius of 100 light years and is 7200 light years away from us. The ionised atomic hydrogen from the young stars intermix with space dust in a manner resembling frothy waves and blue flames. The nebula is expected to a last a few million years, though some of the stars will outlive our sun. In addition, there's a smaller nebula (Sh2-143) that is often overlooked when talking about the magical wizard as well as a supernova remnant (PK107-00.1).
Given that it had been several months since I had done anything, I was a bit rusty and I had a tough time deciding which version to go with so I decided to showcase a few of them so people can decide for themselves (though my favourite choice is the first one and it has the least amount of processing). Most have to do variations in colours of the "blue flames" and "waves" regions as well as the background but the last one was done by creating a starless version of the nebula coloured using the Photometric Color Calibration process in PixInsight (first time doing both!) and then stars from a simpler version were put back in (thanks to Stephen King et al. for introducing me to the star removal technique). The process worked as far as mixing and matching goes, but starting with the PCC (which may have been a mistake or I didn't do it properly) and working my way to the final image via the starless process caused a some loss of detail that is present when using the more conventional approaches. Still, I've included it here to show what I did using the star removal approach.
https://www.astrobin.com/4j0pwf/C/ - different colour choices
https://www.astrobin.com/4j0pwf/D/ - different colour choices
https://www.astrobin.com/4j0pwf/E/ - different colour choices
https://www.astrobin.com/4j0pwf/F/ - Ha only
B actually is the same as the main image but without the sharpened stars using Multiscale Linear Transform. What I did was put up the two images next to each other in two browser windows and swapped between them using my keyboard and couldn't decide but there's a difference with benefits and loss of the "natural/pure" look (if there's such a thing, I mean that the main colour image is minimally processed once I got the master lights for each filter, mostly just SCNR and stretching and slight curves aside from the MLT-based sharpening; the others are varying attempts at it). Let me know if you spot the difference and what you is better:
http://ram.org/images/space/downloads/n ... _test1.jpg
http://ram.org/images/space/downloads/n ... _test2.jpg
As always, thanks for looking!
--Ram
