Hi Greg,
You recently posted to SeeSat ...
>
> Ive had a look at several prediction programs to see if I could find which
> was correct . I attach a specific example and would appreciate if you could
> try your favourite prediction program to see if there is any agreement.
> Whilst the difference in the three programs tried is not terrible it is
> more than my 2 degree field of view will allow.
>
> Time in all cases is South African Standard Time which is 2.0 hours fast on
> UT. Angles in degrees.
>
< ... stuff deleted ... >
>
> Ive always found GUIDE to be pretty good and I also have confidence in Mikes
> program - my one is normally okay but none of them agree.
>
> Almost forgot - my coordinates needed !!
>
> Longitude +18.51284 (East) Latitude -33.94058 ( south ) Alt=10
> metres
>
< ... stuff deleted ... >
>
> Element set used:
> --------------------
> Unknown 041206
> 1 90027U 04841A 06071.55035598 0.00001113 00000-0 11045+1 0 09
> 2 90027 62.3773 158.6750 6940454 268.4454 91.5512 2.00728666 05
>
< ... stuff deleted ... >
Using Rob Matson's Skymap program, which uses SGP4 and SDP4 as warranted by
the TLE, I find the following ...
Summary: (taking specific times) (South African Standard Time - UT+2.0 hrs)
======================================
Greg Mike Guide Matson's Skymap
Time az el az el az el Az El
------ --------------- ---------- ---------------- ---------------
23:35 231.67 12.76 234 15 236.85 19.35 236.76 19.17
23:50 318.14 44.15 321 44 324.07 43.01 323.93 42.99
which is within tenths of a degree of your "Guide" results. Note that,
according to its documentation, Mike's "program uses a simple 'precessing
ellipse' model for the predictions..." and "does not use lunar/solar
perturbations..." which I believe are part of the SDP4 propagation method.
Mike's "highfly"
Clear and dark skies!
Ed Light
Lakewood, NJ, USA
Site 8840, N 40.1075, W 074.2312, +24 m (80 ft)
-------------------------------------------------------------------------
Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:
http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Mar 22 2006 - 07:37:03 EST