Barred Spiral Galaxy in Cetus

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M77 is a barred spiral galaxy, about 47 million light years from us. This galaxy has an inner, brighter ring, and an outer, fainter, ring, similar to M94

This galaxy is almost 100,000 light years in diameter, so almost as large as our Milky Way.

I always enjoy looking at the small background galaxies in many of my images. This one is especially fun that way, with a number along the edges of the outer ring.

The entire field of the uncropped version of the photo is about the same width as a full moon.


Technical Information:

L(HaR)GB: 360:1080:150:180:240 (a total of over 33 hours of exposures); luminance layer consists of blend of 33 thirty-minute images and 18 five-minute images (all using a luminance filter; R channel is a blend of 12 fifteen-minute images taken through a red filter and 12 thirty-minute images taken through an Ha filter; G consists of 12 fifteen-minute images taken through a green filter, while B is the combination of 12 twenty-minute images taken through a blue filter.

Equipment: RC Optical Systems 14.5 inch Ritchey-Chrétien carbon fiber truss telescope, with ion-milled optics and RCOS field flattener, at about f/9, and an SBIG STX-16803 with internal filter wheel (SBIG filter set), guided by an SBIG AO-X/STX Guider, all riding on a Bisque Paramount ME German Equatorial Mount.

Image Acquisition/Camera Control: Maxim DL, controlled with ACP Expert/Scheduler, working in concert with TheSky X.

Processing: All images calibrated (darks, bias and sky flats), aligned, and combined in Pixinsight. Color combine in Pixinsight. Some finish work (background neutralization, color calibration, Noise XTerminater, Blur XTerminator) done in Pixinsight; some finish work (LRGB combination, contrast and saturation adjustment) was done in Photoshop CC.

Location: Data acquired remotely from Sierra Remote Observatories, Auberry, California, USA.

Date: Images taken on many nights during October, November and December of 2023. Image posted June 1, 2024.

Date: Image scale of full-resolution image: 0.56 arcseconds per pixel.

Seeing: Variable, but generally good.

CCD Chip temperature: -25C

Copyright 2023, 2024 Mark de Regt

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