NGC 2903
NGC 2903
Barred Spiral Galaxy in Leo

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NGC 2903 is a barred spiral galaxy, visually located within the constellation Leo. It is about 100,000 light years across (somewhat less than the size of our Milky Way galaxy), and about 30 million light years away from us. NGC 2903 presents to us tilted 60 degrees, so it appears longer than wide.

The amorphous blob to the right of the bottom of NGC2903 is UGC 5806, an irregular galaxy that seems to be gravitationally bound to NGC2903. As with so many astrophotos, it's fun to scan the background of the uncropped image, and see all the tiny galaxies hundreds of millions of light years away.


Technical Information:

(HaL)(HaR)GB: 390:645:180:180:440 (a total of a bit over 30 hours of exposures); luminance layer consists of blend of 43 fifteen-minute images using a luminance filter, and 13 thirty-minute images using an Ha filter; R channel is a blend of 12 fifteen-minute images using a red filter, and the Ha data also used in the luminance layer; G consists of 12 fifteen-minute images taken through a green filter, while B is the combination of 22 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 (using NormalizeScaleGradient) in Pixinsight. Color combine in Pixinsight. Ha data blended into the luminance and color layers in Pixinsight. Some post-processing (background neutralization, color calibration, gradient removal, NoiseXTerminator and BlurXTerminator, done in Pixinsight; some finish work (LRGB combination, 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 late January and early February of 2022. Image posted March 19, 2022.

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

Seeing: Generally quite good, with individual calibrated luminance images having FWHM varying from 1.0 to 1.9 arcseconds.

CCD Chip temperature: -25C

Copyright 2022 Mark de Regt

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