CoSaTrak - Results
Below are a few animated GIFs of captured footage by Greg Roberts' VIDEOTRAK system under computer control of the CoSaTrak Computerised Satellite Tracking software by Willie Koorts.
The original footage was recorded to VHS tape, directly from the output of Greg's low-light surveillance CCD camera, fitted with a 150mm f/2.8 TV camera lens driven by his motorised mount. Frames were then grabbed using a Snappy video capturing device, reduced in size to 320 x 240, some were rotated through 90° (the true orientation) and finally combined into animated GIFs. To show the relative movement, only footage showing some background stars were selected. This reduced the possibilities somewhat, since Greg's system has a field of view of only 1.9 x 1.4 degrees, can see down to about magnitude +7 and the faint stars are lost in the reproduction.
These GIF images can only give a rough idea of the real performance of the system because of big losses introduced in the recording, digitisation and image scale reduction processes to produce these animations. To reduce filesize, frames were reduced to 320x240 and grabbed at about ½-second intervals, resulting in some "jerkiness".
- uhf2rocket.gif (9k)
Some early footage of the UHF2 rocket body passing through a starfield while climbing steeply. No image rotation was done to rectify for the real orientation (the left edge corresponds to the real horizon). This footage was taken before the program was able to centre the satellite on the screen, hence it being on the edge of the field.
- noss6pass.gif (263k)
Two satellites from the classified NOSS6-trio flying in formation through a bright starfield with the 3rd member trailing behind just outside the field of view. They were still quite faint during this part of the pass and brightened to near naked eye visibility later in the pass but did pass through nice a field again. As above, no image rotation was performed here.
- 65027c.gif (226k)
A plastic nose-cone left over from a satellite launched way back in 1965, seen here flaring up nicely as it reflects the sunlight while still climbing steeply during its pass. The real image orientation is represented here.
- 65027a.gif (668k)
The actual payload of the launch above passed over a short while later that same evening. The satellite, being much brighter than its debris, provided a nice show as it passed the Milky Way. This reproduction is unfortunately a far cry from the original footage because of so many losses.
- Iridium 35.gif (693k)
The Iridium communication satellites bacame world famous for producing very bright flashes. Iridium 35 was caught here, doing a -3 magnitude flash while going through a fairly bright starfield. Frames were captured at 1 second intervals to make this animation. Notice how the background darkens as the camera compensates for the bright illumination near maximum, slightly reducing the visual impact.
Greg later upgraded to a more sensitive surveillance camera capable of 0.01 lux. This he fitted to a 135mm focal length f/3.5 still-camera lens to shoot these pictures.
- The "Coathanger" asterism (RA: 19h 26m, Dec: + 20° 00m)
This grouping, known as the "Coathanger" for obvious reasons is an easy binocular target. The image was captured by stacking a number of frames of an AVI file using Astrostack and subsequently processed with AcDsee & LViewPro. The faintest star recorded was about mag 8.5.
- Open cluster (RA: 14h 48m, Dec: -66° 27m)
This interesting field, accidentally stumbled upon by Greg, was processed identical to the one above. The faintest star recorded was about magnitude 8.9 which is quite amazing considering it was done from suburban Cape Town.
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