Obs 27 Dec 2004

From: Greg Roberts (grr@iafrica.com)
Date: Tue Dec 28 2004 - 11:01:02 EST

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    Observations 27 Dec 2004:
    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.
    Used with 82mm focal length f/1.6 lens with focal reducer giving a
    field of view of about  4.94 x 3.54 degrees and showing 10th magnitude 
    stars with a full moon around.
    Conditions CHANGING. Initially good, then full moon came up,
    followed by cirrus then finally cirrus + cloud which forced me to
    Site 0433 : Longitude 18.51294 deg East, Latitude  33.94058 deg S,
    Elevation 10 metres - situated in Pinelands (Cape Town), South Africa
    26473 00 047A   0433 F 20041227182854700 17 15 0947360-625653 39
    26473 00 047A   0433 F 20041227182918800 17 15 1009253-610513 39
    26473 00 047A   0433 F 20041227182946000 17 15 1028417-590301 39
    28385 04 034B   0433 F 20041227184959200 17 15 1919463-853747 39
    28385 04 034B   0433 F 20041227185101000 17 15 1259449-840044 39
    25724 99 023A   0433 F 20041227185645300 17 15 2346348+231412 39
    25724 99 023A   0433 F 20041227185746700 17 15 2354585+243803 39
    25724 99 023A   0433 F 20041227185855800 17 15 0004361+261601 39
    90013 03 564A   0433 F 20041227194200000 17 15 0514230+123653 39
    90013 03 564A   0433 F 20041227184800000 17 15 0420283+114442 39
    14143 83 056C   0433 F 20041227191945900 17 15 2100515-372849 39
    14143 83 056C   0433 F 20041227192040400 17 15 2142150-325803 39
    14143 83 056C   0433 F 20041227192144300 17 15 2238203-230104 39
    14143 83 056C   0433 F 20041227192259500 17 15 2345563-051803 39
    24753 97 012A   0433 F 20041227191458200 17 15 2210322-144722 39
    24753 97 012A   0433 F 20041227191528300 17 15 2219486-080631 39
    90026 04 809A   0433 F 20041227190749600 17 15 0437133-024642 39
    90026 04 809A   0433 F 20041227190827200 17 15 0449108-060339 39
    90026 04 809A   0433 F 20041227191001200 17 15 0525371-152436 39
    90026 04 809A   0433 F 20041227191116400 17 15 0601524-231341 39
    (1) Other satellites seen as strays:
            Cosmos 842 rocket 76070B
            Intelsat 5-2 rocket #12445  80098B at 9400 kms range
            Eutelsat W2 ARK #25493 98056C at 11400 kms range
            65082AT #01680 Transtage 4DbAT ( fast)
            Okean 2 rocket 9001B  #20511
            Intelsat 5-1 Rocket #12497 81050B at 7000km range
          ( these were all seen in the field of view as I tracked
            other objects - probably missed quite a few as well!)
    (2) I have not reported magnitudes as I have not yet thought about
        how to determine magnitudes when the satellite image is trailed
        or integrated. (trailed = fainter, integrated = brighter)
    (3) First tracking session with new camera so mainly experimenting.
        The difference between this camera and a conventional surveillance
        camera is that the camera can add successive frames in memory and
        then dump the integrated image to screen/tape. When used with no
        integration the exposure duration is 1/50th sec for PAL and 1/60th
        sec for NTSC. One can program the camera to do any of the following
        integration frames: 2,4,6,8,12,16,24,32,48,64,96 and 128 frames
        so that a 128 frame would have an integration time of 128/50 = 2.56
        seconds. The frames are shown on the screen continuously, being
        updated evry 2.56 seconds if in (say) 128 frame mode.
        One can also do a 2x zoom( useful for focussing), produce a mirror
        image or a negative image plus lots of other items like putting text
        on the screen, putting a mask at a specified location, change the
        "color" balance etc etc.(camera is b/w)
    (4) At the start of the evening I did Lacrosse 4 in two frame integration
        as the sky was too bright for anything longer. As the sky got darker
        I was able to increase integration to the maximum of 128.
    (5) When used in integration mode the star background appears "fixed",
        although it moves slightly between each frame displayed if the camera
        is kept stationary. However if the camera is driven at sidereal rate
        the stars will appear fixed. The satellite image appears "trailed"
        and the length of the trail is related to the exposure duration and
        the angular velocity of the satellite so this will be very useful for
        unknowns as speed and track angle can easily be determined plus two
        positions per trail ( ie the start and end time of the frame). I
        make the assumption that the integrated image is immediately dumped
        to screen and the moment this happens the time is read and gives the
        end time. The start time would then be 2.56 seconds earlier than the
        end time ( again assuming 128 frame integration).
    (6) The first few satellites I tracked keeping the camera stationary so
        that the satellites trailed. I then came to a satellite which I knew
        would be faint and would not normally be seen with my old setup. I
        then started the camera mount tracking on the predicted position and
        immediately spotted the satellite as a bright "stationary" dot with
        the stars trailing by. Since I was operating in 128 frame mode this
        gives a theoretical increase in magnitude of about 4.5 magnitudes.
        The following are the theoretical gains in magnitude for tracking in
        this mode:
         4x frame integration - exposure 4/50th second - gain 0.8 magnitudes
         8x frame integration - exposure 8/50th second - gain 1.5 magnitudes
        16x frame integration - exposure 16/50th second - gain 2.3 magnitude
        128x frame integration - exposure 128/50 second - gain 4.5 magnitude.
        In future I plan to track only using the 128 frame mode as it makes
        the satellite so much easier to see.
    (7) Is the MINTRON worth the cost ? I say yes and only regret that I did
        not get it earlier but it is expensive. It is quite easily available
        in most countries under a variety of names and the cheapest was
        around $450 US. I paid 400 EUR and got mine from Germany. In the US
        it sells for as much as $700 or so - if memory is correct this is the
        ASTROVID STELLACAM-EX which is IDENTICAL to my MINTRON except that it
        has a hand held control unit. This unit was recently replaced (?)
        with the STELLACAM II for $795 but as far as I can see the only
        improvement is that it can now do 256 frame integration. There are
        other CCD cameras now coming on the market, eg the MEADE DEEP SKY
        IMAGER at a very reasonable $299 but I/we are all waiting to see what
        results Kevin Fetter gets with his new "toy" before buying another
        CCD camera.    If buying the MINTRON be aware that it comes in different
        models - firstly with a 1/3 inch CCD-- will have a 13 in the model
        number, or a 1/2 inch CCD - then has a 12 in the model number. The
        second item is that it is available in two different models-one
        cheaper than the other and obviously less sensitive, so go for the EX
        model. Finally make sure you get a unit suitable for your country- eg
        PAL or NTSC. The model number for my unit is MTV-12V1C-EX and I got
        it from lechner.electric@t-online.de, http://www.lechner-cctv.de.
        (As the saying goes- "I get no commission etc for advertising etc-
        just another satisfied customer!")
    (8) With a standard C mount 25mm f/14 video lens the field of view is
        about 14 x 10 degrees and with 128 frame integration you can see down
        to about magnitude 8.5-10, depending on how dark your sky is. This
        is obviously ideal for looking for new launches or lost satellites.
        If you can track on a predicted position, even if the satellite is
        several degrees "off-track", one should be easily able to spot a fainter
        satellite and then adjust your mount accordingly to track on the
        observed position. I can see I am going to do a lot of hunting for
        "lost" satellites!
    (9) I have still a few improvements to make before I am finally 100%
        happy with my system:
        (i)  it is essential to install an IR filter as lots of stars have
             halos, appear diffuse etc - these are all red stars and invariably
             variable stars. Adding an IR filter provides sharper images as
             well as killing the "soft" images.
        (ii) A DVD recorder is now regarded by me as being essential - too
             much quality is lost in recording to a domestic VHS video
             recorder which has less than 300 lines resolution, whereas the
             camera puts out 600 lines, so I am effectively "blurring" my
             images by writing two successive lines on top of one another.
    (10) Sorry for such a long report but I consider that the future of amateur
        satellite tracking lies with using video systems - it has so many
        advantages and is now far more sensitive than what the eye can do just
        using a telescope. The initial expense is high but technology is
        constantly improving and you get more for your money the longer you
        wait - but dont wait too long - our time on earth is limited!
    Happy New Year to all
    Best wishes
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