@alacant: re: "Are we now saying that shorter exposures are better?"

If you're referring to my post referencing shorter multistar exposures vs longer single star exposures, as I said, "it's complicated". The alignment/coverage/scale of the guide setup, geometry of the multistar constellation, star separations, SNR, the extent to which the mount is polar aligned, any oscillation behavior in the mount, etc., etc all play in the error budget. A well distributed, balanced, fast and bright multistar constellation should outperform a slower single star setup. In practice, there's likely to be one or more other issues in play, so bias errors could be adversely magnified. The answer to "go faster or slower" is likely going to be widely variable among users, and likely variable for the same user/gear on different targets and nights. That said, the anecdotal evidence being suggested by users thus far is pretty encouraging! I think experimenting a bit with exposure durations in the multistar config could be worth the effort. Cheers, Doug

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