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From: Herbert Prinz (no email)
Date: Tue Nov 02 2004 - 22:17:58 EST
Frank Reed wrote:
> Maybe we should experiment. How many occultations can you observe
> during the next couple of months? By the way, if you're excluding
> sextants, should you also exclude binoculars, or do we permit them?
> And you may be able to get away with using the period when the Moon is
> moving with dark edge trailing, too.
Has anybody picked up on my suggestion to watch for occultations during
the eclipse? I would be very interested in observation reports. Those
who used a telescope, how many of the 30 occultations (60 events) I
announced did you see? Why didn't you see them? What was the problem?
> An attentive observer can time emmersions almost as well as
> immersions.
Really? Not me. Is this your own experience? Maybe if you have precisely
pre-computed timings and have made a sketch beforehand to know where
emersion is going to happen. Of course, the problem with comparing
reaction times at both sides of one particular occultation is that you
have immersion at one limb and emersion at the other. (If you see what I
mean.)
Mayer used a micrometer. Now, that's a whole different story!
What you say is more true for Jupiter satellite eclipses, because they
happen at a distance from the bright object. But even then I tend to be
late at both ends. If I were just half blind or had a bad telescope, I
would be early at immersion and late at emersion and the estimate for
mid-event would still be good. But being late at both ends because of
slow reaction is a bad thing, if you want to time the event. I have only
tried it a couple of times, because it's rather rare to be able to see
both ends of the same Jup. sat. eclipse. It's happens mostly for III,
sometimes for IV.
Herbert Prinz
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