So here's an image that surely does not deserve to see the light of day - but it comes with a story related to my quest to someday properly use bayer drizzle.
Last year I shot M42 at super-low gain, but it was when I had not yet sorted out the quirks of my AT130. So some subs were shot with the wider uv/ir-cut (purple stars) and I had not yet chased down the light leaks so I had all manner of problems with flats.
The other night we finally had a bit of clear forecast (albeit the temperature was 15°F - and the wind was blowing 10-12mph).
But I got set up and once M42 got sort-of, but not really, high enough I started taking 15s subs, dithering after each sub.
That didn't go to well. With lousy seeing and the wind, I was losing more than half the time to settling after all those dithers. In the end, the clouds arrived sooner than expected. In fact, at least half of the subs I did collect have thin clouds visible. But when you're whole night's effort results in all of 15 minutes worth of data (60x15s) - you just stack it all, obviously.
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- M42_HCG_60x15s.jpg (478.5 KiB) Viewed 2894 times
Did I learn anything? Yes, I think so.
1) I can take 15s subs at high-conversion gain and still preserve the Trapezium using ST's HDR. Not as neatly as last year with 15s subs at super-low gain, but hopefully I will gain quite a lot of SNR in the dusty bits this way.
2) Dithering every 15s is a disaster. At least with PHD2. Next time I will use the Ekos internal guider. Why? Because it has this smart setting called "1-pulse dither". They figured that if each dither move is to a new position chosen by a random-number generator, why put any effort at all into trying to land at exactly the new chosen position. Anywhere close to it is just as random - so give the mount one move command per axis, and call it good.
3) HDR created black holes in the middle of a bunch of stars. No idea what's up with that or if it will also happen with an actually serious stack, but worth keeping an eye on and maybe being ready with a pre-HDR star mask for an undo.