Re: Has Gorizont 23 stopped flashing???

Jason Hatton (
Thu, 23 Jul 1998 09:21:13 +0000

> At 02:41 PM 7/22/98 +0000, I wrote:
> >Hi Everyone,
> >               A while back I posted a message to alert European observers about the
> >possibility of observing the bright flashing Geosat Gorizont 23
> >(91-046A, 21533). Normally this flashes approx. once every 50s at about
> >mag +5, like a celestial lighthouse, so it is quite easy to spot in
> >binoculars & small scopes. Usually this is a **very** reliable flasher.
> >Well finally the sky cleared up enough a couple of days ago, so I tried
> >observing Gorizont 23 in my 6" scope & guess what - there was no sign of
> >it!
Ron Lee wrote:
> Seems unlikely that it would have stopped. I suspect that you are seeing
> a phasing / sun angle problem.  If I recall correctly, I have had trouble
> seeing it as well even in an 8"  .   Just need to look at it at a
> different time.

I finally caught a glimpse of Gorzont 23 at 21:10UT last night
(22-Jul-98) in my 6" Scope. It is still flashing, but no brighter than
mag +8. What made it particularly difficult to see was very poor
transparency / light pollution meaning that my scope couldn't reach more
than about mag +9 (determined using Uranometra as a reference), so it be
would be more obvious under beter conditions. I agree with Ron that the
most likely reason for Gorizont 23 being fainter than a few months ago
is an unfavourable phase angle between sun satellite & observer. Timing
11 periods I got a flash period of 50.55sec, so it looks like the period
is still increasing.

Best wishes & clear skies,


Jason P Hatton
ETS Strasbourg
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67065 Strasbourg Cedex

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