Railfan_Bill wrote:
Hi Ballard, Great shots of the Fireworks Galaxy. Unfortunately, my little 8 inch RC could not do this justice as you have. I do have a question: why did you use 2 x 2 binning? Is it only for file size or trying to reduce the star bloating in the Milky Way stars?
Thanks for viewing the images of NGC 6946 and for the comment. On previous images I was using 1x1 binning however at 4000mm it means that each pixel is ~.19 arcseconds (Note: camera pixel size physical size with the ASI 6200mm pro is 3.76 um). Since this size is below the resolution of the scope (~.25 arcseconds) along with the fact the RMS tracking rarely gets below .4 seconds for the duration of each subframe it was a waste to go that small, so I have started using 2x2 binning. With 2x2 binning I still get a resolution of .38 arcseconds/pixel, this it also makes for much smaller files (30 meg vs 120 meg) saving space, processing time and increases the effective welldepth of the 2x2 binned pixels. Note: when using my 500mm F 4.0 canon lens I still only use 1x1 binning as this can use the extra resolution which is of 1.55 acrseconds/pixel at the 500mm focal length.