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Astrophotography by Bob Franke

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NGC 1491

 

Click the image for a 64% size wide field view. (2400 x 1600 - 2.13 MB)

Instrument

12.5" RCOS @ ~ f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at  1.00 and 3.20 arcsec/pixel.

Mount

Paramount ME

Camera

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

Acquisition Data

1/5/2012 to 12/27/2014 Chino Valley, AZ. with CCD Commander & CCDSoft.  AOL guided

Exposure

Lum

330 min (22 x 15 min. each) Bin 1x1

RGB

720 min (16 x 15 min. each) Bin 2x2

Ha

600 min (20 x 30 min. each) Bin 1x1

Software & Processing Notes

 

  • CCDSoft, CCDStack, PixInsight.

  • PixInsight PhotometricColorCalibration for color balancing.  eXcalibrator failed on this one. :-}

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

  • CCDStack to calibrate all sub exposures.

  • PixInsight processing includes CosmeticCorrection, data  rejection, mean combine all sub-exposures, create the LRGB image, gradient removal, non-linear stretching with HistogramTransformation, BackgroundNeutralization, HDRMultiscaleTransformn, NBRGB to add the Ha data, Gaussian Convolution for mild background smoothing, StarNet to create a star mask and  the GAME script to make a mask for the bright nebula core.

Comment

 

The nebula is shown rotated 45 counterclockwise.

NGC 1491 (Sh2-206 or LBN 704) is a bright irregular emission nebula, about 10,700 light-years away in the constellation Perseus.