NGC7741

[sreilly]

So after finding the dark master issue I have re-calibrated all of the luminance data and culled the images taken on NGC7741 and have to see if the difference in the resulting 62 frame (15.5 hours) of luminance data is worthy. The raw image seems to show a good deal of what I believe they call inf (background dust) or if it's artifact in the image. How does one tell for sure? I know I have an artifact in the lower center from the field flattener and some off frame star in the upper right but what appears as dust around the galaxy and it's many background galaxies is all over the image. Where is the definitive answer found?

[sreilly]

The first posted image has been processed in PI but I also used a plugin in PSCS5 for gradient removal. The image went through the normal process of calibration, cosmetic correction, alignment, culling of the 110 frames using the best 62 (900 secs each), and combined using Linear Fit w/median combine. The resulting image was cropped (dithered exposures), DBE was used twice (subtraction + division), masked stretch was used, HDRW was used, curves was used to increase contrast, and then the image was saved. On one version I simply saved as a TIFF 16 bit, at 1600 pixel width and the second I brought into PSCS5 and ran Russel Crowman's Gradient Exterminator which resulted in the background becoming more "normal" but maybe not an accurate display. The real question is there galactic dust in this image or is it a "bad" process or other problem with the data?

This image shows the image as processed without using the Gradient Exterminator plugin and totally processed in PI.

[sreilly]

Actually both seem too light for the dust to be seen. Maybe this one will be more evident.....