Re: Has anyone seen daylight Iridium flares?

Craig Cholar (3432P@VM1.CC.NPS.NAVY.MIL)
Fri, 17 Apr 98 23:34:00 PDT

Alister Ling <> asked about observing Iridiums
in the daytime:

>I did some considerable planning by locating the Alt-Az of the flare
>ahead of time: The night before I would find the spot on the sky
>(through astronomy software) with the anticipated alt-az then find a
>spot in my backyard where I could line up the alt-az with a wire or
>chimney top. The next morning I would put my feet back in the same spot,
>then look up at my reference point and shift my position slightly so as
>not to have the flare occur behind my reference point. No luck visually.
> ...
>So naturally I am begning to wonder if the predictions are working for
>other observers. Any luck out there? What technique did you use?

Alister, your technique is fine.  I've used the same method to see
daytime flares, as have others.  One possible problem is that your
daytime predictions were for Iridiums that haven't reached their
operational orbit, such as the seven launched on the recent Proton
launch.  If the mean motion in the elset isn't around 14.34 then
chances are the predictions won't be correct.  Case in point:  I
had a prediction to see five of the new Iridiums flare to between
mag +2 and mag -1 a few days ago.  Nothing was seen using 1x power.

The other possibility is your 7x50 Fujinons are defective.  I'd
be glad to trade yours for a pair of 25-year old Bushnells bought
on special at K-mart that now live under the front seat of my car.
I anxiously await for e-mail from you so we can make arrangements
on making the swap. ;-)

 Craig Cholar    3432P@VM1.CC.NPS.NAVY.MIL