NGC 474, the odd-looking galaxy toward the bottom right of the image, is an elliptical galaxy, about 100 million light years from us. This galaxy is unusual for its combination of concentric shells and tidal tails, thought to be tell-tales of a long-ago (more than a billion years ago) collision with a smaller spiral galaxy, which ultimately was absorbed into NGC 474. NGC 470, the small spiral galaxy just to the left of NGC 474, which is also about 100 million light years from us, may also be causing some disturbanc in NGC 474, but I'm dubious, given the lack of distortion in NGC 470. Also note the tidal tails on NGC 467 well above and to the left of NGC 474, indicating that it, too, has been involved in one or more collisions; NGC 467 is thought to be about 200 million light years from us.

NGC 474 is almost 250,000 light years in diameter, more than twice as large as our Milky Way (itself a very large galaxy).

I always enjoy looking at the small background galaxies in many of my images. This one is especially fun that way, with a great number throughout the uncropped image.

This image was an exercise in faith--almost nothing of the shells and tidal tailes show up on a single 30-minute subexposure. Only by combining a lot of them does the signal overcome the background, and the very faint stuff becomes visible.

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

Technical Information:

LRGB: 1010:180:180:240 (a total of almost 27 hours of exposures); luminance layer consists of blend of 25 thirty-minute images, 20 ten-minute images and 20 three-minute images (all using a luminance filter; R channel is a combination of 12 fifteen-minute images taken through a red 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 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 September and October of 2025. Image posted February 6, 2026.

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

Seeing: Variable, but generally ok.

CCD Chip temperature: -25C

Copyright 2025, 2026 Mark de Regt

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