# Re: Almost time for flaring GEOSATS

From: Cees Bassa (c.g.bassa@phys.uu.nl)
Date: Fri Mar 02 2001 - 12:21:42 PST

• Next message: Alan Pickup: "Decay watch: 2001 Mar 2"

```>Last year Rainer Kresken posted info on seeing GEOSATS flaring just prior
>to Earth shadow entry. The dates as a function of latitude are below and
>we are approaching that time for the northern hemisphere.
>
>latitude    optimum date (Day/month)
>-80          01/09
>-60          04/09
>-40          09/09
>-20          15/09
>0            23/09
>+20          30/09
>+40          07/10
>+60          12/10
>+80          15/10

I've tried to compute these days for myself but I got different results.
When I calculated the
day for, say a latitude of +40°, I found September 9 instead of October 7,
the result belonging
to the latitude with the other sign.

After some thinking I found out why: I assumed that the solar panels of the
satellites track the
sun, but I guess Rainer Kresken assumed they didn't. This explains why the
dates belonging to
the latitudes get swapped. A simple correction was made in my program so
that it does give the
right results.

Now I'm wondering if all geostationary satellites keep their solar panels
fixed, i.e. they don't track
the sun. It seems very plausible, but I can imagine that it is a little
effort to let the panels track the sun. Are there any geosats with solar
panels that do track the sun?

Here is my list for the March 20, 2001 Equinox, with and without tracking
solar panels:

Without        With Tracking
Latitude   Month/Day Month/Day
80.0000    2 26        4 12
60.0000    2 28        4 10
40.0000    3  5        4   6
20.0000    3 12        3 29
0.0000    3 21       3 21
-20.0000    3 29        3 12
-40.0000    4  6        3   5
-60.0000    4 10        2 28
-80.0000    4 12        2 26

So for me here at latitude +52° the optimum for non-tracking satellites has
just passed, and
clouds are keeping me inside for way too long now.

Regards,
Cees Bassa

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