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Contains:  IC 4895, Barnard's galaxy, NGC 6822
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Barnards Galaxy in HAOIIILRGB

Technical card

Resolution: 2810x1888

Dates:July 12, 2019

Astrodon Blue: 19x900" -30C bin 1x1
Astrodon Green: 20x900" -30C bin 1x1
Astrodon Ha 5 nm: 15x1200" -30C bin 1x1
Astrodon Luminance: 26x900" -30C bin 1x1
Astrodon OIII 3 nm: 6x1200" -30C bin 1x1
Astrodon Red: 20x900" -30C bin 1x1

Integration: 28.2 hours

Darks: ~20

Flats: ~20

Bias: ~20

Avg. Moon age: 10.52 days

Avg. Moon phase: 80.98%

Bortle Dark-Sky Scale: 3.00 job: 2795360

RA center: 296.203 degrees

DEC center: -14.809 degrees

Pixel scale: 0.728 arcsec/pixel

Orientation: 80.765 degrees

Field radius: 0.342 degrees

Locations: Sierra Remote Observatory, Auberry, California, United States

Data source: Own remote observatory

Remote source: Sierra Remote Observatories


One of our local group neighbors, only 1.5 millions light years distant, this dwarf galaxy remarkably resembles one of our Magellanic Clouds. It may be small but it is alive with bright blue giants, and star forming regions.

To best capture the star forming clouds I shot both Ha and OIII to add to Red and Blue respectively. I tried a different method for integrating the narrowband data with the broadband. Using linear data in CCDStack, I first subtracted the mode of the narrowband image. That reduced the background counts of the Ha for example, to near zero. Then I added the result directly to the linear red. Subtracting the background meant that I carried a minimal amount of the Ha noise over to the Red channel. This produced a very bright red for the nebulae however. Next time I will divide the Ha file by 2 or 3 before adding to the linear Red channel.

The Ha and OIII data were also added to the Luminance channel. I used Pixelmath and Filemath functions in CCDStack. Non-linear processing was done in PS CC 2019.



Kevin Morefield
License: None (All rights reserved)




Sky plot

Sky plot


Barnards Galaxy in HAOIIILRGB, 


            Kevin Morefield