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    Re: Cook's Endeavour voyage, longitude by lunars and jupiter's moons
    From: Norm Goldblatt
    Date: 2013 Sep 28, 14:59 -0700

    I wonder if any amateur has applied the principles of photometry to precisely determine the occultation of a Jovian moon. I bet it's easier than detecting the change of illumination when a star goes behind the moon, due to the brightness difference.

    In terms of the size of the telescope, I suppose that a larger telescope might make it easier, but increasing the aperture of a telescope does only 2 things.
    1. decreases the minimum angular resolution. But this is only a linear relationship ( double the telescope aperture, halve the minimum distance between two sources that allow observation of two distinct sources.

    2.Allows higher magnification with same resolution. Probably not a big advantage. Again, it's linear- images are twice as big- but often bigger is also blurrier.

    Oh, and by the way, go to Orion Telescope on web and compare the weight of a 4 inch and an 8 inch telescope of similar design and don't forget to include the weight of tripod!
    Best to observe when the altitude is high, and where atmospheric effects are minimum. This, in turn depends on many meteorological factors.
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