Pagman wrote in post #18491418
Many thanks Roy I will see what I can produce next time.
After you asked how many images you needed to stack, I got curious to see what sort of difference it would make to stack a few, compared to stacking a bunch. Last month, I experimented with taking a lot of short exposures to stack with the camera on a standard tripod, so I used those images to see how much difference it would make. I had 297 exposures at 6 seconds each to stack. The exposure and stacking information is at the bottom of the pictures. For the stack of 10, I just used 10 of the 297 exposures I had in the file. They are the same images.
Apparently, I spent a LOT of time making more exposures for a tiny bit of difference. 287 more images resulted in a little more detail in the nebula! Dark skies and long exposures are what makes the difference in detail - not stacking a lot of pictures taken in light polluted areas, and having to underexpose to avoid having the ambient light in the sky wash out the picture. For good detail in faint nebulae, a tracker is absolutely necessary to make longer exposures, and a dark site makes the real difference! A single 20 minute exposure with a dark sky will produce a much better image than a stack of 300 from a light polluted area. At least that's been my experience... lots of people on here seem to be able to get all sorts of fantastic results in highly light-polluted cities, but I have no idea how they can! Filters can only do so much, and require even longer exposures.
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