Object: M104 (NGC 4594)
Constellation: Virgo
Distance: 31,000,000 light years
Date: 18th & 19th April 2018
Equipment: SXV-H9, Vixen 114mm f5.3 ED refractor, NEQ6 mount, guiding with Lodestar X2/PHD
Subframes: 70 x 200s luminance, 5 x 200s each for RGB 2 x 2 binned), 20 darks and bias frames, 20 flats for each channel (image stacking, hot pixel and gradient removal in Astroart, curves and colour composition in Paint Shop Pro).
I had never attempted to image this galaxy before, and thought it might be a bit of a challenge given its low location in the southern sky, which for me is also blighted by light pollution from the Aurora Maidstonealis. M104 is quite a small object (in visual terms, of course!) for a relatively small aperture but I was curious to see how it would turn out.
In terms of imaging, I find that light pollution filters don't really offer any contrast boosting effect, and that image processing seems to be a better option to offset light sky backgrounds.
Given that these were the first clear nights in nearly six weeks I couldn't really ignore the opportunity even though the seeing wasn't great and the sky not truly dark (high haze, I think). On the plus side, the moon was new and caused no glare problems. Nevertheless, the conditions led to somewhat noisy sub-frames with gradients that I scrubbed up as best I could using the nifty Astroart gradient removal plug-in, plus noise flattening in PaintShop Pro (curves and edge preserving smooth). I don't normally bother with dark frames but it did seem to help with the background noise in this case. My ancient SXV-H9 camera is not set-point cooling regulated and so maybe the warmer weather is adding a dose of electronic noise to my subs.
The output is never going to win any prizes of course, but in the end I was sort of OK with this effort, even if it only shows the dust lane and little else.
Equipment: SXV-H9, Vixen 114mm f5.3 ED refractor, NEQ6 mount, guiding with Lodestar X2/PHD
Subframes: 70 x 200s luminance, 5 x 200s each for RGB 2 x 2 binned), 20 darks and bias frames, 20 flats for each channel (image stacking, hot pixel and gradient removal in Astroart, curves and colour composition in Paint Shop Pro).
I had never attempted to image this galaxy before, and thought it might be a bit of a challenge given its low location in the southern sky, which for me is also blighted by light pollution from the Aurora Maidstonealis. M104 is quite a small object (in visual terms, of course!) for a relatively small aperture but I was curious to see how it would turn out.
In terms of imaging, I find that light pollution filters don't really offer any contrast boosting effect, and that image processing seems to be a better option to offset light sky backgrounds.
Given that these were the first clear nights in nearly six weeks I couldn't really ignore the opportunity even though the seeing wasn't great and the sky not truly dark (high haze, I think). On the plus side, the moon was new and caused no glare problems. Nevertheless, the conditions led to somewhat noisy sub-frames with gradients that I scrubbed up as best I could using the nifty Astroart gradient removal plug-in, plus noise flattening in PaintShop Pro (curves and edge preserving smooth). I don't normally bother with dark frames but it did seem to help with the background noise in this case. My ancient SXV-H9 camera is not set-point cooling regulated and so maybe the warmer weather is adding a dose of electronic noise to my subs.
The output is never going to win any prizes of course, but in the end I was sort of OK with this effort, even if it only shows the dust lane and little else.
Good old Wikipedia tells us more about this object here...
