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Astrophotography by Bob Franke

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Hickson 61 - The Box

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Click the image for a ~ 57% size wider view. (1800 x 1200 - 1.02 MB)

Instrument

12.5" RCOS @ ~ f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at  0.85 and 1.11 arcsec/pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ FW8 filter wheel & AstroDon Gen-2 LRGB filters.

Acquisition Data

4/18/2017 to 4/25/2017 Chino Valley, AZ.  with CCD Commander & CCDSoft.  AOL guided

Exposure

Lum

510 min (17 x 30 min. each) Bin 1x1

RGB

405 min ( 9 x 15 min. each) Bin 2x2

eXcalibrator RGB ratios are 1.00, 1.18 & 1.33

Software & Processing Notes

 

  • CCDSoft, CCDStack, PixInsight, Photoshop CS6.

  • eXcalibrator v5.0 for (g:r) color balancing, using 37 stars from the SDSS-DR9 database.

  • CCDBand-Aid to repair KAI-11000M vertical bars.

  • CCDStack to calibrate all sub exposures, data reject and combine the color data and create the RGB image.

  • PixInsight to register, normalize, data reject, combine the luminance sub exposures, gradient removal, non-linear stretching with HistogramTransformation and to create the LRGB image. Selective use of HDRMultiscaleTransform, with various layer counts, was used to enhance the detail of the galaxies.

  • PhotoShop for the final touch-up.

Comment

 

Shown rotated 75 clockwise.

Hickson 61, A.K.A The Box, is compact galaxy group in the constellation Coma Berenices. The topmost galaxy is NGC 4175. Continuing clockwise, the galaxies are NGC 4173, NGC 4170 and NGC 4174.