Hemisphere:  Northern  ·  Constellation: Perseus (Per)  ·  Contains:  Double cluster  ·  NGC 869  ·  NGC 884  ·  The star 7Per
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Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
Perseus Double Cluster - NGC 869 and NGC 884
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Perseus Double Cluster - NGC 869 and NGC 884

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Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
Perseus Double Cluster - NGC 869 and NGC 884
Powered byPixInsight

Perseus Double Cluster - NGC 869 and NGC 884

Technical card

Imaging telescopes or lenses: Sky-Watcher Esprit 120

Imaging cameras: ZWO ASI1600MM-Cool

Mounts: Paramount MyT

Guiding telescopes or lenses: Orion StarShoot Autoguider

Software: PHD2  ·  Astro Pixel Processor  ·  PixInsight 1.8 Ripley  ·  Main Sequence Software SequenceGeneratorPro

Filters: Astrodon Red Tru-Balance E-Series Gen 2  ·  Astrodon Green Tru-Balance E-Series Gen 2  ·  Astrodon Blue Tru-Balance E-Series Gen 2

Accessory: ZWO 8x 1.25" EFW  ·  Moonlite Nitecrawler 2.5 Nitecrawler 2.5 Focuser  ·  Alnitak Astro Flip-Flat Flip-Flat


Dates:Nov. 25, 2017

Frames: 187x60"

Integration: 3.1 hours

Avg. Moon age: 6.28 days

Avg. Moon phase: 38.39%


Basic astrometry details

Astrometry.net job: 2067006

RA center: 2h 20' 49"

DEC center: +57° 9' 14"

Pixel scale: 0.912 arcsec/pixel

Orientation: 2.475 degrees

Field radius: 0.717 degrees


Resolution: 4550x3376

Locations: Home Observatory, Wake Forest, NC, United States

Data source: Unknown

Description

NGC 869 / 884 in Perseus - RGB

Shot 100 each of R, G, B, kept 66 R, 49 G, 72 B. Shot 500 L's and decided that L didn't add anything to this after processing as RGB and LRGB both. L had some saturation that resulted in blotchy color in a few of the brighter stars.

Pre-processed with the new 1.060 AstroPixelProcessor which has multi-channel processing. I think it does a great job.

Then over to PI for ABE 3 times, DBE once, MLT Noise Reduction, HistogramTransformation, TGV Denoise, a bit of Curves to boost contrast and saturation, and a bit of color touchup with Saturation. Actually reduced the red a bit as some of the red stars looked unnatural to me.

Brought into Photoshop CC for Bodoni tools' "increase star color" which had a subtle effect, and resized and saved. And here we are!

A bit of what looks like chromatic aberration is visible in the brighter stars (red fringe on one side, blue on the other). I don't think it's from the optics as I haven't seen it in other shots with the same rig. I think it may be alignment, maybe red and blue taken on opposite sides of the meridian? AstroPixelProcessor's "align channels" option cleaned this up considerably compared to the result I was getting in PI.

Comments and criticism welcomed, always looking for ideas to improve!

Thanks for stopping by,
Rowland

Comments

Revisions

  • Final
    Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
    Original
  • Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
    B
  • Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
    C
  • Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer
    E

B

Description: 1920x1080 sized version

Uploaded: ...

C

Description: 800x600 sized version

Uploaded: ...

E

Description: Re-processed using APP's quality estimator for integration weighting instead of SNR. Also a bit less contrasty, slightly lighter BG

Uploaded: ...

Sky plot

Sky plot

Histogram

Perseus Double Cluster - NGC 869 and NGC 884, 



    
        

            Rowland Archer

In these public groups

ZWO ASI1600MM/QHY163M