Observations 22 Sept 2004:
--------------------------------
Cosatrak 1 (Computerised satellite Tracking System), 1004x low
light level CCD surveillance camera (0.003 lux) with 50mm focal
length f/1.8 lens .
Conditions fair - transparency did not look that great.
Site 0433 : Longitude 18.51294 deg East, Latitude 33.94058 deg S,
Elevation 10 metres - situated in Pinelands (Cape Town), South Africa
11389 79 050A 0433 F 20040922175756430 17 15 1948088+364616 39
05679 71 110B 0433 F 20040922180651680 17 15 2016363+275314 39
05679 71 110B 0433 F 20040922180716700 17 15 2027204+234658 39
05679 71 110B 0433 F 20040922180756050 17 15 2046158+161222 39
25744 99 028A 0433 F 20040922181830100 17 15 1603015+004126 39
25744 99 028A 0433 F 20040922181932100 17 15 1615208+051527 39
25744 99 028A 0433 F 20040922182028000 17 15 1626010+091548 39
25744 99 028A 0433 F 20040922182129100 17 15 1637021+133828 39
25744 99 028A 0433 F 20040922182236950 17 15 1648428+181833 39
21798 91 082A 0433 F 20040922183628130 17 15 1314262-680028 39
21798 91 082A 0433 F 20040922183656470 17 15 1407102-633120 39
21798 91 082A 0433 F 20040922183714770 17 15 1434266-594459 39
21798 91 082A 0433 F 20040922183744970 17 15 1509048-520613 39
24753 97 012A 0433 F 20040922184022390 17 15 1016017-825601 39
24753 97 012A 0433 F 20040922184054080 17 15 1400424-825706 39
24753 97 012A 0433 F 20040922184057270 17 15 1420471-823536 39
24753 97 012A 0433 F 20040922184115500 17 15 1544330-791904 39
24753 97 012A 0433 F 20040922184120780 17 15 1600435-780940 39
26473 00 047A 0433 F 20040922185716530 17 15 1409572-265854 39
26473 00 047A 0433 F 20040922185750590 17 15 1354501-333149 39
90013 03 564A 0433 F 20040922190204200 17 15 2221268+004931 39 S+084 02
Notes:
~~~~~~
(1) Willie Koorts has made (and is making) some major changes to the
computer program (CoSaTrak) that controls my CCD tracking system.
This was originally done with a view to mass production of observations
should the amateur community be required to track several
hundred (thousand?) satellites. The bottleneck in producing more
observations has been the manual measuring/reduction of observations
from video tapes recorded during a tracking session. The new system is
now almost operational and the computer automatically records time
azimuth and elevation as well as the RA and Dec of any object (converting
from observed epoch to J2000) and outputting data in the format used
above. This means that the altazimuth mounting must be set up reasonably
accurately, instrument pointing errors determined, and by applying
Toshimi Taki's two star alignment routine it is hoped that
ultimately the observations reported are as accurate as possible.
I believe there is a three-star alignment routine for setting up
a mounting - does anyone have the algorithm ? - Meade apparently uses
it with some of their GOTO telescopes but I have been unable to locate
code for the procedure and understand its a real hairy procedure!
It was also necessary to accurately control the computer internal
clock as this drifts and this time is used in reporting a position.
The computer clock can now be automatically set once every minute
using an external clock controlled by a GPS unit.
The program is still being beta tested and so far results are
encouraging with errors of around 0.2 degrees or so. It is hoped
to reduce this still further as there are still a few items to do,
such as accounting for backlash in the system and ensuring that the
system does not loose calibration. This will mean installing a
selsyn/magslip/synchro system so that one can spot a loss in
calibration which can occur from time to time and will be a
disaster if not immediately detected.
Finally Willie has switched over to Free Pascal as it is superior
to Turbo Pascal used previously - as a result of this routines run
faster which means the mount has to be re-calibrated in terms of
tracking and slewing speeds and this can take quite a few
observing sessions to optimize - I am pretty close now but not
100% satisfied.
(2) The observations reported above were derived from the video
tape as in the past.
Cheers
Greg
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