Re: Iridium Flares ground projection
J.C. Millot (papou@canl.nc)
Wed, 4 Feb 1998 12:16:11 +1100
Hi all
>> shadows. does venus cast visible shadows? i've heard of bright meteors
>> (-8, -10 range i would assume) casting them. who knows? so who among you
>> is going to be the first to turn your back on a monster-flare to look for
>> your shadow?
>
>I've seen shadows cast by Venus. On a recent Iridium flare (magnitide
>-5.6) I turned my back to look on the ground but saw nothing. I think it
>would be quite difficult!
>
>It was easier (for Venus) to be inside a dark room & see the patch of
>light moving slowly across the wall. Once you found the patch of light,
>it was fairly easy to make a shadow. The same trick would be hard for a
>short-duration Iridium flare!
>
>Best, Mark
>--
>Mark Hanning-Lee, markhl@prodigy.net
>
I used this trick to see a shadow cast by Jupiter at opposition (It was
mag -2.5 I think).
Put on a white T-shirt or sweatshirt.
Wait for Jupiter to be at an altitude of 45 degrees or so.
Put your hand in front of you so that Jupiter can cast a shadow on your
T-shirt.
Now you will have to wait for the same sort of conditions with Iridiums
satellites.
Hope this helps.
Another trick to compare magnitude of a crescent moon and a bright Iridium
flare:
take a low power pair of binoculars and look at the moon through the wrong
side of the binocs. The moon should be concentrated to something looking
more like a dot than with one power. Try different powers of binoculars.
Try o look a Venus too.(Mag -5)
The 7 day moon is said to be mag -9 I think.
Then imagine the middle of these two bightness and you get mag -7.
Then imagine some brightness in the middle of -5 to -7 and you get -6, same
thing for -8.
If you have a bright light away from you about this bright like a spot or a
lighthouse this could help too.
So practice now and then get ready for the monster flare. My best one is
mag -8 up to now.
Than be ready for you bright Iridium flare with the same binocs. I find it
easy to compare.
Hope this helps.
Any remarks about these methods are welcome.
Jean-Christophe 'Papou' Millot - email : papou@canl.nc
Consultant en Technologies de l'Information - IT Consultant
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