26 Sept 2006
Object name: NGC 7331
Object type: Galaxy
Magnitude: 10.3
Size: 10.2 4.2
Position angle: 17
Classification: Sbc
Apparent RA: 22 37 05.1
Apparent Dec: +34 25 13
Constellation: Pegasus
Please see below for notes....click on image to view in separate browser...
One of my old favourites, NGC 7331. This galaxy is abot 49 million light years away, and makes a nice image presentation with companion galaxies NGC 7336, 7335, 7340, 7337, 7325 and 7326. Various other very faint fuzzies also pepper the field. I have taken over 3 hours of unfiltered L data and about 30mins each of R, G and B. I am pleased with the depth of this image, and the barred spiral structure starting to show in NGC 7337.
I find that the outer regions of the galaxy always seem much dimmer than I remember - even with a lot of exposure it is difficult to get low noise and good detail in these regions.
The faintness of the outer regions also makes colour difficult without very large amount of colour data. As you can see, parts of the outer regions are going a bit grey due to lack of colour data. Pushing the saturation would just make it noisey.
Guiding was suffering from some flexure - an area I've been working to correct, however, because I'm making some ongoing modifications, I've not paid attention to the correct optical alignment, and, with the poor guiding, star shapes have suffered.
Due to the large number of frames, the background noise has dropped spookily low.. normally I process images with a slightly brighter background than this!
Previous efforts:
Captured in Artemiscapture. Calibrated in ImageViewCA. Combined in Maxim. Colour balance in Maxim. Smidge of RL. LRGB layering and finishing in photoshop
This image was autoguided using my 400mm focal length refractor and my black and white SC1 webcam.
Current Imaging equipment configuration
Exposure Details :
Coma Corrector 94x120s on 200mm @ F5 with ART285
Coma Corrector G 12x120s on 200mm @ F5 with ART285
Coma Corrector R 12x120s on 200mm @ F5 with ART285
Coma Corrector B 12x120s on 200mm @ F5 with ART285
Curdridge Observatory, Southampton,UK
