Re: How visible are flares???

Willie Koorts (
Wed, 27 May 1998 09:43:33 +0200 (GMT+0200)

On Tue, 26 May 1998, JRBURCA wrote:

> In a message dated 98-05-26 19:48:59 EDT, Ed Troy wrote:
> << I've been watching this list for a while now, and I've been trying to see
>  the flares, but, so far, to no avail >>
> A possible source of confusion is that not all books and software agree
> on azimuth.  Most satellite tracking and all Iridium flare software calls due
> north 0 degrees, due south 180 degrees.

Another common mistake most people make is to under-estimate Altitude.  Ask
anyone to point at alt. 45 and they would more often than none point at about
alt. 30 degrees.  Ask them for 60 and they will give you 45. Knowing about
this problem at work, we take this into account when dealing with the general
public and tell them indirectly to look higher than normal - eg. when
something is expected at alt. 60, tell them "overhead" (which is roughly 
when one's head locks when tilted max. backward). Just using the 
simple rule of an outstreached hand (from thumb to pinkey) at armslength = 20
degrees works well to measure angular distances in the sky. 

Using the GSOC website is the best to ensure sightings since the 
non-performers are filtered out for you.

Hope you will get Iridiated soon!

                        Willie Koorts   

       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

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