Quote:
Originally Posted by Hagar
Looks good Bert, but what a huge image to scroll around!!!
Have you done some form of star reduction or min filter as there seems to be the tell tail spider web in the tight star fields. I notice this when I do either on my images. It's only visible in the full size image.
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Yes you are correct Doug. See this thread for more info
http://www.iceinspace.com.au/forum/s...ad.php?t=50530
Here is the same image reduced to about the native size of the 5D's sensor (4368x2912 pixels) 6.3MB
http://d1355990.i49.quadrahosting.co...ifenhcnatr.jpg
It is better to enhance at about twice native size otherwise you end up with lovely square stars. This is due to the fact you are sampling diagonally at x1.4 the horizontal and vertical sampling interval, that is the pixel spacing. Dithering actually means that the sampling approaches the nominal pixel spacing in all directions as you stack more images at x1.4 native pixel spacing. I put the large image up to show how well this all works. In fact it is effectively equivalent to having a sensor with twice the number of pixels in the same area. In the case of the Canon 5DH that is 25 MP at full frame.
Bert