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Work in progress
Started this Saturday night. I love these galaxies and been wanting to image them a long time.
So far, only 30 x 60s L and 10 x 60s RGB.
C11 with focal reducer (1760mm), ASI183mm Pro. Astrodon filters. Mesu 200. Pixinsight.
Thanks for looking
70 x 300s H-alpha, 16 x RG&B, 300s each, no darks (hot pixel removal in Astroart instead).
Subframes were stacked in Astroart, the outputs converted to TIF files and then colour-composited in PaintShop Pro.
The colour data was a bit of a pig to process with the software I have. First of all it became apparent that 300 second subs probably weren't long enough. I had to stretch the resultant stacks quite a way to get any decent detail, which introduced more noise than I really wanted. Then the blue colour stack turned out to be a slightly different size to the others, despite all being full frame without any need to resize. I always refocus between filter changes as the colour correction on my old Vixen 114 ED refractor is not brilliant, so I guess this was the cause, particularly on the blue channel. This made it difficult to stack the images for colour composition. I did my best to manually rotate and resize in PaintShop, but the stars still show some odd haloes where the channels didn't quite line up.
I made two colour images, one created by the addition of green and blue channels (20 x 300s subframes for each) to the H-alpha image above, which was used as the red channel for an RGB composite. This was a rather violent red, as anticipated, so I blended it with an HaRGB stack, which was the usual washed-out pink. The blend gave a reasonable depth of colour. The blue brilliance of the brighter stars in the cluster has led to some reflection flaring around them. I find the effect quite pleasing, however.
The “Fox Fur Nebula” (Sharpless 273) can be seen below S Monocerotis in the above image. Its resemblance to road-kill is quite remarkable, even in this modest image. The bluish area arises from the reflection of starlight from dust in the region. Some images show this reflection nebulosity to be much more extensive than seen here, probably because I did not compensate for the poorer blue sensitivity of the CCD with longer blue subs.
The Christmas Tree Cluster is visible to the naked eye in good conditions and appears quite striking in binoculars. The stars forming the Christmas tree shape, along with dozens of other tiny bright stars within the cluster, are a magical sight as seen in my VC200L with a 25mm eyepiece. None of the associated nebulosity is visible however, at least, not to me.
This image may compete for being one of the worst framings ever.
It is an RGB image that I processed from free data from the Liverpool Telescope, a 2 m RC reflector on La Palma. This time with quite a lot of data, so not much noise and a lot of detail. The "only" problem is that the astronomers requesting the subs must only have cared about NGC 3187 and the beautiful NGC 3190 just happened to be partly included.
Found this nice info about these galaxes on the Canary Islands Astronomical Institute www.iac.es:
Discovered by Sir William Herschel in 1784, NGC 3190 and NGC 3187 are two spiral galaxies seen nearly edge-on. The spiral arms of NGC 3190 are tightly wrapped around its nucleus, and those of NGC 3187 are S-shaped. Both galaxies are located in the constellation Leo and are members of the Hickson 44 galaxy group, located about 70 million light years from Earth. The galaxies in this group are very close to each other so that gravitational interactions are common, resulting in a high degree of shape distortion and a high rate of star formation in many cases. This gravitational dance will eventually end up in many galaxy mergers.
Filters and exposures used (from 2015 01 21 - 2016 04 26).
sdss-r 40 x 90 s (red channel)
Bessell V 23 x 90 s (green channel)
Bessell B + sdss-g 53 x 90 s (blue channel)
Hickson Compact Groups (HCGs) are small, isolated system of four or more galaxies in close proximity to one another. The magnitudes of the galaxies differ by less than 3.0. Hickson identified 100 such compact groups.
One is HGC 44 in Leo, sometimes known as the NGC 3190 Group. with members: NGC 3190; 3185; 3187; NGC 3193.
This is data from DSW in new Mexico. Takahashi FSQ 106; Paramount MyT; WSI 683 with Astrodon LRGB filters.
Lum: 16x900s Red: 17x900s Green: 14x900s Blue: 16x900s Total: 15 hours 45 minutes.
Processing in PI and PS.