Re: Iridium 18 flare (Venus vs. Iridium)

Willie Koorts (wpk@saao.ac.za)
Tue, 4 Nov 1997 09:50:10 +0200 (GMT+0200)

On Sat, 1 Nov 1997, Jake Rees wrote:

> A few months ago, I tried to see Venus perhaps 1-2 hrs. before
> sunset using 7x35 binoculars.  I didn't know *precisely* where to
> look so was scanning around.  Finding it was difficult and tedious
> and took some time.  Then once found, my thought was "Wow,
> that's bright; why did it take so long to see it?"  

And Ron Lee replied

> Part of it is focusing on the object.  In a clear sky, you eye does
> not naturally focus at infinity.  I have does this mucho times.
> 
> Once you find the star/planet...it become seasy, but that initial
> acquisition is hard at times.

I often thought about this before and in talking to others came to the the
conclusion that it is probably due to two factors - focus, like Ron just
explained.  Jake's explenation above just about sums up the second problem -
"scanning around".  If you can just hold your eye still for long enough to
"integrate" enough light onto the retina to form an image which the brain can
recognise, it becomes easy.  Have you ever tried spotting Venus in daytime
when it sits next to the moon?  You cannot believe how easy it is.  If fact
as we speak (4 Nov) the Moon is only 9 degrees South of Venus!  This is where
Leigh Palmers suggestion of putting a treetop where you expect Venus/Iridium
to be/glint comes in so handy. 

Willie

         Willie Koorts   wpk@saao.ac.za   http://www.saao.ac.za/~wpk/

       Cape Town,  Observatory   33d 56' 03"S   18d 28' 36"E   GMT + 2h
       Wellington, South Africa  33d 38' 56"S   19d 00' 52"E   GMT + 2h