Hemisphere:  Southern  ·  Constellation: Sagittarius (Sgr)  ·  Contains:  Checkmark Nebula  ·  IC 4706  ·  IC 4707  ·  Lobster Nebula  ·  M 17  ·  NGC 6618  ·  Swan Nebula  ·  omega Nebula
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Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO, 



    
        

            robonrome
Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO
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Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO

Getting plate-solving status, please wait...
Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO, 



    
        

            robonrome
Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO
Powered byPixInsight

Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO

Technical card

Imaging telescopes or lenses: APM LZOS 130/780

Imaging cameras: ZWO ASI294MM Pro

Mounts: iOptron CEM70

Guiding telescopes or lenses: PrimaLuceLab 240mm guide scope

Guiding cameras: zwo asi224 mc

Focal reducers: Riccardi RIRED-M63

Software: Aries Production astro pixel processor  ·  Photoshop CC  ·  StarTools 1.7

Filters: Antlia SII 3.5nm  ·  Antlia 3.5nm Ha  ·  Antlia 3.5nm OIII

Accessory: ZWO EFW 36mm  ·  ZWO EAF Focuser  ·  PrimaLuceLab ECCO ECCO  ·  PRIMALUCE LAB Eagle 3s


Dates:June 9, 2021

Frames: 192x300" (16h)

Integration: 16h

Avg. Moon age: 28.67 days

Avg. Moon phase: 0.83%


Basic astrometry details

Astrometry.net job: 4605857

RA center: 18h20m36s

DEC center: -15°5830

Pixel scale: 1.616 arcsec/pixel

Orientation: 3.421 degrees

Field radius: 0.915 degrees


Resolution: 2717x3041

Locations: Backyard, Brisbane, Queensland, Australia

Data source: Backyard

Description

Those southern hemisphere winter (such as it is here in Oz) targets are starting to get higher in the sky beckoning for all nighter image sessions.

This image of my old friend the Swan Nebula was taken over 3 nights. Very few subs lost to clouds, but still losing a few (and star quality) from guiding/flexure issues when I image more toward my zenith as here... tossed 20% or more subs due to such, and probably should have dropped more as the seeing last night really bloated things, but APP is pretty good at weighting such out a lot so not so bad.

Not used here, but I have just taken possession of a ZWO OAG and ASI290mm mini cam which I will be trying soon to see if they help resolve my guiding issues near zenith...we shall see. Also a neat little weight attachment I picked up that can put some assymetric weight on the main counter-weight shaft ...just attached that and adjusted and now get pretty precise balance...something the iOptron mounts really seem to need.

Anyway, that's for next time... back to this image.

Stacked in APP and separated into Ha, OIII, and SII... I combined as GBR in APP and saved as a TIF for later composite with Startools result into PS, as I like using some of the colour constrast and stars from the combined APP tif output. Recombined individual FITs files for the three channels and processed as SHO in Startools 1.7. Ivo (Startools developer) recently gave me a useful tip to reduce purple halos and tint that SHO combinations often yield... simply process through to end noise reduction then open in Layer module set Invert FG, keep, then open in Colour Module setting Green cap to 100%, keep, open again in Layer Module and again set Invert FG, keep and done!

The Startools result is the major contributor here but I did some low-percentage (¬25%) colour and normal blend of the APP TIF file to taste in PS. Final tweaks in PS.

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Swanning around the galaxy on the Swan Nebula - M17 in narrowband SHO, 



    
        

            robonrome