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The galaxy NGC7331 is located in Pegasus and is approximately 46 million light years distant. It's estimated to be be substantially larger than our own Milky Way with a transverse diameter of 140 000 light years. Some background galaxies can also be seen in the image (below), which are estimated to be c300 million light years distant Due to its high inclination of 77 degrees, part of the disc is blocked by dust lanes, although I was quite pleased with the amount of detail captured.
The LRGB image represents 11.5 hours integration time and was taken with my Esprit 150.
This is doing my head in. OK, there's only 6 hours RGB and 2 1/2 hours Luminance binned 1x1 as yet but the colour balance is doing my head in.
Looking at NGC 7331, I would expect to see a yellowish core and sparkling blue arms, but the coer is blueish and the arms a nondescript mud
Images through my 13 f/7 triplet and Trius 694 with Baader filters.
Stacked with sigma Average and Bias only in AstroArt 5, Trichromy with Auto levels and White Balance then LRGB synthesis. The resultant image just had DDP, then saved as FITS and JPEG.
I wondered if I'd got the filters in the wrong order (Done that before with NB) but they're OK.
Any ideas? I do have Maxim DL6 on the office computer, but it looks a steep learning curve compared to AstroArt.
Well, my last image of 2016 - the Deer Lick group and Stephan's quintet. I've also included an annotated version for the galaxy hunters. Constructive comments and criticism is welcome.
The image is an LRGB and represents about 7 hours integration time, it was going to be a bit longer but I decided to discard quite a few subs due to poor seeing conditions.
I also had a bit of a struggle trying to get (what I hope) is the correct colour for the main galaxy (NGC7331). My conclusion is that when processing RGB data, I should first use Pixinsight's Linear Fit route to achieve colour balance before attempting DBE or Colour Calibration - any thoughts on the optimum order for application of these functions would be appreciated.
LIGHTS: L:14, R:9, G:10; B:8 x 600s. DARKS: 30; BIAS 100; FLATS:40 all at -20C.