Messier 94 is a spiral galaxy in the constellation Canes Venatici.  Measuring 11.2' × 9.1', it is among the larger galaxies in the northern sky by angular size.  M94 appears to have a double ring structure, though the outer "ring" consists of weakly defined spiral arms according to a recent study.[1]

M94 passes nearly straight overhead at my location, which always is helpful with image quality.  This project got off to a strong start in February due to an unlikely streak of excellent imaging nights that are otherwise a rarity in my location during February.  Unfortunately, the following months afforded less additional imaging time, so it took three months of data collection to finish this project.  I ended up with uneven integration time in the RGB channels due to a scarcity of clear skies the past month, but I think I got enough of the blue and green channels to make it work.  I collected 70 minutes of H-alpha that was not included in the final LRGB image simply because I did not like the effect it had.  Many of the bright blue regions in the central disk emit H-a, so it's a judgment call as to whether it helps the image or not.

There are not many background galaxies in this image that are large enough to show structure.  The image has been cropped for the sake of framing the subject, and I processed it at the native image scale of 1.4" per pixel.  Most of the subs are 300 s, Mode 3 (Extended fullwell 2CMS-1), Gain 14.  I also acquired some short luminance subs (75 s) simply for the sake of patching up the cores of brighter stars that were overexposed with the 300 s subs.  Noise reduction was performed via Topaz AI on the starless image, which was blended with the original (noisy) image to lower the noise levels just slightly without excessive smoothing.    The "B" revision is just a tight crop for those viewing the image on a small screen.


1.  Trujillo, I., Martinez-Valpuesta, I., Martinez-Delgado, D., Penarrubia, J., Gabany, R.J. and Pohlen, M., 2009. Unveiling the Nature of M94's (NGC4736) Outer Region: A Panchromatic Perspective. The Astrophysical Journal, 704(1), p.618.