Re: Should I use my BARADV for the upcoming lunar eclipse?
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Nick, Daniel You prompted me to translate a document that I have used in several talks. It presents the (simple) equations leading to the 5 x pixel rule of thumb. The original was in French. You can find the English version here: A note on tracking: a 15 second exposure is quite a long time unguided. Especially on the moon which doesn't travel at the sidereal rate. The lunar rate setting on APCC is only approximate since the lunar rate varies during the lunar cycle. And it's RA only so doesn't account for declination drift. So halving that to 8 seconds could be quite a good thing. Why on earth would you like to expose 15 seconds on the Moon? I mean, imaging the Moon is like taking a photograph of a brightly sunlit rocky landscape (it *is* a brightly sunlit rocky landscape). With the usual cameras the subexposure time is in the order of one to five milliseconds. Ideally you take thousands of them with a video camera, and this only takes several minutes at most, during which the Moon does not have to stay strictly at the same place on the sensor. Stacking programs like AutoStakkert!3 will take care of the drift afterwards. I simply set my mount to the Moon rate, and from time to time I adjust the declination manually during or between the movies. Good luck! Daniel -------------------------------------------------------------------- Daniel Borcard Observatoire du Geai Bleu Clear Sky Chart: http://cleardarksky.com/c/ObGBlQCkey.html?1 Le ciel est assez grand pour que chacun y trouve sa place. -------------------------------------------------------------------- |
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