Casitas de Gila, Gila, NM
April 17, 2021

Reprocessed 02/20/2023

Original:

During my April 2021 astrophotography trip to Casitas de Gila, Gila, New Mexico, a target that intrigued me was NGC 5128, Centaurus A galaxy in the constellation Centaurus.  The was a very challenging object that was very low in the southern sky and allowing only about three hours to image.  I had taken several test frames of Omega Centauri which showed atmospheric turbulence distortions.  Centaurus A is a few degrees above Alpha Centauri.  Sky conditions allowed me one night to capture as many subframes as possible.  I ended up using all of the subframes.  The result is an image deficient in detail and color and containing bloated stars.  The image does show the dark and distorted dust lane around the bright elliptical galaxy center.  Thus, this was a “how low can you go?” experiment.  In this case, the altitude was near 20 degrees.

Reprocessed:

This was a salvage operation.  Centaurus A was very low in the sky and a minimum amount of data were captured.  Any improvement was welcomed.

I continued my effort to reprocess most of the image data sets that had flaws and issues using new PixInsight tools and an improved workflow.  Again, Russ Croman’s XTerminator tools, and PixInsight’s WBPP, SPCC and GHS process tools made a significant difference in improving the imaging and simplifying the workflow.

Description:

Centaurus A is a peculiar lenticular galaxy, type S0.  However, recent measurements make it likely to be an elliptical galaxy with a supermassive black hole at the center.  It is 12 Mly from Earth, and it is about 90 kly in diameter.  NGC 5128 is the result of a merger of two smaller galaxies.  The bulge consists of mostly old red stars.  The striking disk is an area of recent star formation. (SkySafari Pro 6)

Imaging details:

Celestron 9.25" Edge HD SCT
Celestron 0.7x Focal Reducer (FL = 1645mm, f/7)
Celestron off-axis guider with a ZWO ASI 174MM mini guide camera
Celestron CGEM II mount
ZWO ASI 1600MM Pro cooled monochrome camera (-15C)
ZWO 36mm Luminance, Red, Green and Blue filters

Software:    Sequence Generator Pro, PHD2 guiding, Celestron CPWI mount control, 
    PixInsight and Photoshop CC 2021/2023

Luminance    2 min x 35 subframes (70 min), Gain 139, Offset 21, 1x1 binning
Red        4 min x 11 subframes (44 min), Gain 139, Offset 21, 1x1 binning
Green    4 min x 10 subframes (40 min), Gain 139, Offset 21, 1x1 binning
Blue       4 min x 10 subframes (40 min), Gain 139, Offset 21, 1x1 binning