Obs 10 Feb 2005

From: Greg Roberts (grr@iafrica.com)
Date: Fri Feb 11 2005 - 11:30:56 EST

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    Observations 10 Feb 2005  
    --------------------------------
    Cosatrak 1 (Computerised satellite Tracking System).
    MINTRON low light level CCD surveillance camera (0.005 lux typical
    in non integration mode) and 0.00005 lux in STARLIGHT mode with 128
    frame integration. Due to bright sky it is not worthwhile integrating
    more than 48 frames which is equivalent to an exposure of 0.96 seconds.
    
    Data recorded on DVD R/W disks - will be kept for 1 month and then
    re-used - just in case any queries as Im always making mistakes!
    
    Site 0433 : Longitude 18.51294 deg East, Latitude  33.94058 deg S,
    Elevation 10 metres - situated in Pinelands (Cape Town), South Africa
    
    (1) Lens used :  70mm focal length f/1.3 (ex cine camera). Field of
    view  5.0 x 4.0 degrees, magnitude limit +12. After these observations
    considered not suitable for positional work as a result of severe
    vignetting and severe "white" flooding of the field of view at elevations
    less than 20 degrees due to city light glare - extremely sensitive to
    light level variations.
    
    24753 97 012A   0433 P 20050210183028600 17 15 0208565-554458 39
    24753 97 012A   0433 P 20050210183041400 17 15 0215555-503815 39
    24753 97 012A   0433 P 20050210183057800 17 15 0222556-434813 39
    24753 97 012A   0433 P 20050210183122200 17 15 0230305-331751 39
    25725 99 023B   0433 P 20050210183835700 17 15 0307529-114055 39
    25725 99 023B   0433 P 20050210184010100 17 15 0332112-100019 39
    25725 99 023B   0433 P 20050210184113300 17 15 0349257-084003 39
    23947 96 038C   0433 P 20050210184340200 17 15 0356303-005933 39
    23947 96 038C   0433 P 20050210184442600 17 15 0410484+051402 39
    23947 96 038C   0433 P 20050210184603200 17 15 0430038+134114 39
    28385 04 034B   0433 P 20050210190141500 17 15 1903454-761453 39
    28385 04 034B   0433 P 20050210190200200 17 15 1758382-780750 39
    28385 04 034B   0433 P 20050210190219400 17 15 1625030-784101 39
    
    (2) Lens used : 50mm focal length f/1.8 ( ex 35mm camera). Field of
    view 6.9 x 5.5 degrees,magnitude limit +11. After these observations
    considered not suitable for positional work due to the poor image
    scale on account of the large field of view - also very sensitive
    to light level variations in the sky and low elevation observing
    difficult due to "white out" - whole field of view just goes white
    with no details at all.
    
    90013 03 564A   0433 P 20050210195210800 17 15 0822480+122842 39
    90028 04 846A   0433 P 20050210194058000 17 15 0505380-011831 39
    90028 04 846A   0433 P 20050210194123900 17 15 0510120+000351 39
    90028 04 846A   0433 P 20050210194149900 17 15 0514330+012240 39
    90028 04 846A   0433 P 20050210194220600 17 15 0519210+025110 39
    90028 04 846A   0433 P 20050210194253200 17 15 0524070+041806 39
    90028 04 846A   0433 P 20050210194343100 17 15 0530530+062456 39
    28538 05 004B   0433 P 20050210194625600 17 15 1420060-625832 39
    28538 05 004B   0433 P 20050210194702000 17 15 1346420-585756 39
    24680 96 072A   0433 P 20050210202551200 17 15 1456380-610113 39
    24680 96 072A   0433 P 20050210202632400 17 15 1401080-612333 39
    24680 96 072A   0433 P 20050210202657100 17 15 1321460-603835 39
    28537 05 004A   0433 P 20050210200910600 17 15 1519140-732044 39
    28537 05 004A   0433 P 20050210200950500 17 15 1408460-693707 39
    28537 05 004A   0433 P 20050210201114400 17 15 1247190-564949 39
    28537 05 004A   0433 P 20050210201219400 17 15 1218310-445356 39
    28541 05 004C   0433 P 20050210200910600 17 15 1619340-744200 39
    28541 05 004C   0433 P 20050210201016200 17 15 1410210-695248 39
    28541 05 004C   0433 P 20050210201139900 17 15 1247240-570750 39
    28541 05 004C   0433 P 20050210201243300 17 15 1218530-452835 39
    
    Notes:
    ______
    
    (1) I was out of operation for a few days due to problems with the
    elevation stepper motor constantly loosing calibration and not pointing
    where the computer said it was. After checking all the cabling and
    connections, as well as the electronic circuitry, it was decided that
    the stepper motor was faulty. This was replaced with a different motor
    which meant the entire elevation component had to be rebuilt. Some work
    still remains to be done but my elevation speed is now twice what it
    was before and the vibration is considerably less.
    
    (2) A very poor night with much cloud - I only bothered to try and get
    the satellites considered important. 96072A was running early as were
    the new NOSS 3-3 objects.
    
    (3) The tests carried out with various lenses has proved that a fast
    optical system is no good for my bright citylit sky. With fast lenses
    I have to wait until the sky is really dark and observing at low
    elevations is difficult. The MINTRON camera is extremely sensitive to
    light, especially when used in integration mode. It now appears that
    lenses faster than about f/2.5 should be avoided and lenses with a focal
    length of less than about 100mm are not really suitable for positional
    work.
    
    (4) Strays seen and identified:
    
     TSX5 #26374 00030A  magnitude 7.5 steady
     Noaa 6 regular flashing
     Stardust Del Rkt 99003B #25619  mag +7.1 steady at 4890 km range.
    
    (5) Next tracking session monday or tuesday - with waxing moon moonlight
    will be a problem in about 10 days time.
    
    Cheers
    Greg
    
    
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