Spiral Galaxy in Canes Venatici

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M94 is a magnitude 9 galaxy in Canes Venatici, presenting to us face-on. It is particularly interesting because of the two rings, evident in this photograph, around its nucleus. The inner ring, mostly blue, is about 7,000 light years in diameter, and is an intense star-forming region (full of bright, young blue stars). The outer ring, much fainter, is about 45,000 light years in diameter. It is speculated that the cause of these two rings is pressure waves emanating from the galactic nucleus.

It is estimated to be approximately 16 million light years from earth, and approximately 100,000 light years in diameter. It is thought, unusually, to be almost devoid of dark matter.


Technical Information:

HaLRGB: 380:495:180:180:240 (that's over 24 hours of keepers included in this image); Ha data consists of 19 twenty-minute images, woven into both the luminance data and the red-filtered data. Luminance layer consists of data from 33 fifteen-minute images through the luminance (clear) filter (plus the Ha data); R, and G consist of fifteen-minute images; B consists of twenty-minute images. I gathered Ha data to enhance the pink star-forming regions. All images were unbinned.

Equipment: RC Optical Systems 14.5 inch Ritchey-Chretien carbon fiber truss telescope, with ion-milled optics and RCOS field flattener, at about f/9, and an SBIG STX-16803 monochrome camera with internal filter wheel (SBIG filter set), guided by an SBIG AO-X, 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 Professional Edition.

Processing: All images calibrated (darks, bias and sky flats), aligned, combined and cropped in Pixinsight. Color combine in Pixinsight. Some finish work (background neutralization, color calibration, deconvolution, HDR Mulitscale Transform and Multiscale Linear Transform of luminance data and noise reduction) done in Pixinsight; some cleanup finish work was done in Photoshop CC.

Location: Data acquired remotely with my equipment hosted by Sierra Remote Observatories, Auberry, California, USA.

Date: Images taken on many nights from April and May 2021. Image posted June 8, 2021.

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

Seeing: Generally excellent, with individual calibrated luminance frames varying from 1.0 to 1.7 arcsecond FWHM.

CCD Chip temperature: -25C

Copyright 2021 Mark de Regt

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