Re: [Re: Cassini/Huygens Saturn probe flyby]

Bjoern Gimle (b_gimle@usa.net)
10 Feb 99 14:30:50 MET

Tony Beresford wrote:
...
> The URL      http://ssd.jpl.nasa.gov/horizons.html
> gets you to a site where you can generate ephemerides of planets, satellites
> and spacecraft( DS 1,Cassini,NEAR

...

Thanks, Tony! I went there and got RA/Dec/AU Range (geocentric) by
giving 'Location Code'=500, and converted RA to Long. by subtracting
'Greenwich Siderial Time' from it. I used 149600000*AU - 6375 for
height in km.

Cassini moves in during the early afternoon of Aug.18 and Aug.17 local
time, since it makes an S-shape over the International Date Line,
going S near the equator. It might be visible from New Caledonia, but
it moves East and enters shadow when closing in. Sunlit again in the
morning hours Aug.17 over South America, long. 90W to 47W.

For a SkyMap 'MapTime' of Aug.18 1999 00:00 UT, the following is a part
of my .trj file (seconds, Long, Lat, Height) for the pass. The ones with
.0 in Height are in (or close to) shadow:

12120	-10.1422	-171.2586	3574
12240	-14.4821	-160.9409	2355.0
12360	-19.2215	-147.1519	1508.0
12480	-23.2435	-130.1432	1169.0
12600	-25.2490	-112.0939	1408.0
12720	-25.0712	-96.0433	2174.0
12840	-23.6258	-83.5134	3337
12960	-21.7986	-74.2936	4766
13080	-20.0338	-67.5826	6367
13200	-18.4780	-62.6460	8077
13320	-17.1501	-58.9530	9859
13440	-16.0262	-56.1440	11689
13560	-15.0735	-53.9770	13552

A complete file for every 2nd minute of Aug.18 is available at my
cassini.htm page (linked from my home page). I can add the Excel
sheet for recalculating the .trj file with new data, or for a different
map time, if anybody desires.

Bjorn Gimle

-- bjorn@tt-tech.se (office)  b_gimle@algonet.se (home)      --
-- 59.2237N, 18.2286E, 44 m   http://www.algonet.se/~b_gimle --
-- 59.298 N, 18.104 E, 55 m   from 1999-01-25                --
-- SeeSat-L / Visual Satellite Observer Home Page found at   --
-- <http://www.satellite.eu.org/satintro.html>       --


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