Quote:
Originally Posted by Placidus
Thanks again, Allan. The images were dithered. We do that routinely, but we can see that we need to increase the dithering distance because our camera produces very strong ghosting from the hourly focus run, and we need strong dithering to avoid these ghost images overlapping each other.
As you know all our camera control, acquisition, and processing software is our own. I don't yet understand the mathematics of drizzling, and until I do, our images will sadly go undrizzled.
Best,
Mike and Trish
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Thanks Mike,
I don't claim to fully understand the mathematics of drizzle -
it's simply explained here with a mouse over example
& of course the DSS software is free:
http://deepskystacker.free.fr/english/technical.htm
& in much more mathematical depth here:
http://iopscience.iop.org/article/10.1086/338393/pdf
I prefer to just try it & see if it can make a difference.
It may not work so powerfully for you as I doubt that you're under sampled?
I prefer to think of drizzle as extra information that is hiding in your data
that can be used rather than as a trick.
Talking of tricks -
when I first watched
Ken Crawford's "digging out the details" video
I thought - he's cheating - "finger painting" so to speak.
Then when I thought about it - he's not -
certain areas of any deep sky image will have a greater
signal to noise ratio than others.
To do a global sharpening would falsely enhance noise & make
the picture look worse but
in other areas where the signal to noise ratio is higher, then
more sharpening using a blurred layer mask is not cheating -
it's just making the most of your data -
it's adding the icing on the cake.
I look forward to seeing your results with extra data.
cheers
Allan