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Re: (ATMoB:Discuss) Re: Occultation by Nephele next Saturday evening
> WWV? It may be a newbie question.. so please excuse. I'm an AAVSO
Estimating magnitudes isn't important - stopwatch isn't good enough unless
you happen to be at a location that just misses the asteroid and reporting that
nothing happened can be very useful.
The idea is that if a whole array of people time the moment this 6th mag star disappears
and reappears (may happen many times over 10 seconds if you are at the graze
point or maybe just once) then the outline of the asteroid can be mapped and satellites
of the asteroid might be found.
To do this very well, it is best to use a video camera with WWV pumped into the audio
and just hold the video camera up to the eyepiece of a telescope. This 6th mag star
is bright enough that a 3 inch telescope should be plenty of aperture.
You should also know your lat and longitude within a few feet of accuracy. Then just
mail in the video tape and timings can be made with 1/30 second accuracy. There are
lots of little simple details to note - for example turn off that anti-bounce feature that
delays video by a few frames. So you should read Peter's pdf file and follow a few
links that talk about this subject. If you have the equipment and live in Mass or NH
it would really be a shame not to gather this data and not much trouble really. It is
rare that such a large asteroid occults such a bright star right here in the boston area
and at a convenient time of the day/week (as opposed to 3am wednesday?). One should
also practice once the night before by finding the same star and making sure it is visible
with a camera.
You can later get a map of all the timings across the object (which looks like a bunch of
lines that start and stop and help show the shape/outline of the asteroid). For more than
2 people to be at the same site (like the clubhouse) would be a waste.
- George Roberts
mailto:gr_a_t_pobox dot com
http://www.pobox dot com/~gr
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