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My effort from Derry last night - once I remembered to remove the cover from the field flattener. Doh.
I know the North America Nebula is done to death, but this is my first time imaging it, and also my first time trying the Triad filter with my Nikon. I'm in the middle of the city but I was able to take 5 min subs! I processed in PixInsight, but didn't even have to do background extraction. I used photometric colour calibration to restore natural colour and then just did a bit of mild tinkering. I'm impressed by the Triad filter on my first try.
Comments welcome - maybe I should try a star mask and try to bring out star colours?
22 X 5 min subs - 1hr 50min integration
PixInsight for calibration / registration / processing
Mount - Vixen AXD2
Scope - TEC 180FL
Camera - Nikon D750
I'm still transitioning from an unmodified Canon 200D to an Altair Astro 183C pro. I think this might be my best image yet, and the first time I have tried a mosaic.
Its made of two panels, each panel has 20x120s + 30x60s. Stacked and stitched in Astro Pixel Processor and edited in PS CC 2018. I'm pretty pleased!
Scope is a SW ED80 DS pro (reduced to 480mm, f/6) on a HEQ5 pro. Guided with a QHY5L-II in my finderscope.
I've spent the day at the keyboard documenting some image processing techniques and as the skies have been so poor, I've had to use some old data for the screen shots but this one worked out OK with the new work-flow.
A Wall of Ionization
NGC 7000, the North America Nebula, is a very popular deep sky imaging object and its rich Ha emission content makes it particularly appealing for RGB imaging. However, I like to capture this region of the Milky Way in Cygnus using narrowband filters to really bring out the detail in ‘The Wall’.
As well as the predominant Hydrogen Alpha (Ha), this object is also quite rich in doubly ionised Oxygen (OIII) emissions. The position of OIII emissions in the light spectrum, right on the cusp between green and blue, allows a full RGB colour image to be produced from just two sets of filter data by using the OIII data for both the green and blue channels and the Ha data for the red channel.
Mount: Mesu 200
Telescope: William optics FLT98
Reducer: William Optics FR IV
Camera: QSI 683 WSG-8
Filters: Baader 8nm Ha and 8.5mm OIII
Subframes: 19 x 900 sec OIII, 19 x 600 sec Ha
Control: CCD Commander
Capture: MaxIM DL
Post-Processing: MaxIM DL and PS3
Following on from the 'free' widefield picture - https://stargazerslounge.com/topic/286774-free-rider-wo-star-71-and-horsehead/#comment-3142262 - here is the image through my Esprit 120. This is 8 hours in total. Last night we had a 'half-moon', more or less, and it was not too far away from the Horse. The Ha subs in both the Esprit and the WO looked about the same as they had done when there was no moon about. SGP does an Autostretch of downloaded subs. The 'black point' of the moonless and half-moon shots were only about 100 ADU apart, which I thought was pretty good. Rather foolishly I wasted time last night trying to get some LRGB. A 5 min Lum sub, autostretched by SGP, had an ADU in the high 8,000s (and looked pretty horrible)! Looks like I will have to wait for the disappearance of Moony McMoonface before taking on the LRGB acquisition.
So this is:
Skywatcher Esprit 120 Astrodon 3nm Ha - 24 x 20 minute subs = 8 hours QSI 690 I've tried not to go too 'extreme' with the processing:
Nice to have a few clear nights for a change!
I finally managed to include some darks and flats . These are different versions of a set of 4 X 256s sub-frames. I think I prefer the less processed one (a) - the stars are less bloated.
Any critique/advice welcomed!
Borg 55FL f/3.6; Atik 490 EX colour