Observations 08 July 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. Used with 25m focal length f/1.4 lens,integrating for 64 frames, thus giving an equivalent exposure of 1.28 seconds.The field of view was 14.3 x 11.6 degrees and faintest star seen was about magnitude 9.2. Theoretically I should have got about a magnitude fainter but transparency was poor and image focus was not as sharp as I would have liked. The lens came from a surveillance video camera and, whilst maybe good enough to see crooks, was not good enough for stellar points. Not all lenses are high quality. Site 0433 : Longitude 18.51294 deg East, Latitude 33.94058 deg S, Elevation 10 metres - situated in Pinelands (Cape Town), South Africa 21798 91 082A 0433 F 20050708172456900 56 15 1518070-004810 39 21798 91 082A 0433 F 20050708172516100 56 15 1507420+052839 39 21798 91 082A 0433 F 20050708172536600 56 15 1457220+113231 39 91034 05 189LEO 0433 F 20050708174145600 56 15 1520560+095253 39 91034 05 189LEO 0433 F 20050708174157200 56 15 1523050+091751 39 91034 05 189LEO 0433 F 20050708174207400 56 15 1525180+084113 39 91034 05 189LEO 0433 F 20050708174218900 56 15 1527400+080107 39 91034 05 189LEO 0433 F 20050708174220200 56 15 1527520+075503 39 91034 05 189LEO 0433 F 20050708174227900 56 15 1529290+072624 39 91034 05 189LEO 0433 F 20050708174238100 56 15 1531590+064421 39 Notes: --------- (1) After having nearly completed my geostationary project I am now looking for greener pastures in satellite tracking so decided to try wide angle tracking to investigate feasibility of locating lost satellites etc. Over the next few sessions I will be testing out various camera lenses/techniques with my MINTRON camera. (2) This session I set the camera on RA 15h00m Dec +05deg00min which is in the Clarke belt and let the CoSaTrak computer program drive the altazimuth mounting at sidereal rate for four hours which is the recording duration of one DVD disk at medium resolution. At the same time I ran a PC program called SKYPATROL which was designed for observing meteors. I then "abandoned" the equipment whilst it ran unattended and went and watched TV for the next few hours. Every minute a "summed" image of all frames obtained in the previous minute ( 1500frames) is displayed and saved to a BMP file on the hard drive.This produces nearly the same effect as taking a 1 minute exposure at night with an ordinary photo camera, however you do not see more stars but all objects that were seen in the previous minute are recorded at their "normal" intensities. At the end of the tracking session ( say of 4 hours duration) one has approximately 240 BMP images and one then examines each image to see what happened in that minute. Satellites and meteors appear as trailed objects as well as other objects such as aircraft,birds etc, whilst stars/planets appear as point sources since the camera tracked at sidereal rate. If the subject looks interesting one can then go to the DVD recording to examine the 1500 frames recorded in that particular minute.Each frame is time stamped so positional information can be derived. It is much quicker to check 240 BMP images than sit through watching 4 hours of recording. (3) At least 14 satellites were seen as follows: 90055D #20666 SL-6 R/B(2) 78039B #10793 Delta 1 R/B(1) 93016B #22566 SL-16 R/B 91082A #21798 DMSP B5D2-6 77005B #09786 Delta 1 R/B(1) 99045B #25893 SL-8 R/B 76108B #09510 SL-8 R/B 94077B #23405 SL-16 R/B 93056B #22788 Atlas Centaur 87074G #18340 SL-14 R/B 61031C #00204 SL-14 R/B 80098B #12445 Atlas Centaur Since 91028A is a satellite appearing in CLASSFD.TLE I measured three positions. However due to the image scale the positions will not be as accurate as those obtained with the 145mm focallength lens normally used for positional work ( being about 6x more "course") (4) An unknown LEO satellite was observed for which I can find no match in my element database. This was fairly slow moving,about magnitude +7.5 at maximum to invisibility with a fairly regular variation. (5) No geostationary satellites were seen as such since I obviously was not able to go faint enough, however three possible flashers were seen (- still to be investigated), one of them being SATCOM 1 flashing about every 51 seconds to about magnitude 7. (6) My conclusions re this lens was that the field of view was too wide for precise positional work and the magnitude penetration is not sufficient for most optical tracking (this applies to my particular city lit skies). An altazimuth mount is not suitable for driving at sidereal rate as field rotation is particularly noticeable when close to the meridian.Ideally a true equatorial mount should be used. (7) On the 9th July I tested a photographic camera (film) 50mm f/1.8 lens but have still to examine the results but first impressions are that the optical quality was good and I probably got another 2 magnitudes fainter.I scanned the same area as on the 8th July. More tomorrow after I have examined the results etc. (8) A program such as SKYPATROL was written to make an AVI recording whenever a meteor was seen. I am certain that the program can be used to operate in the same way with satellites. The detection sensitivity appears to be adequate and I was in fact able to see satellites in the BMP image that I missed in real time. Satellite observed in the BMP images should be ideal for photometric use such as brightness and magnitude variations as these are clearly shown. I intend to try at least one session with completely automated tracking of satellites in the CLASSFD.TLE elements database with me not being in attendence. I think it can be done on most satellites of interest. Other meteor detection programs are available- such as UFOCapture ( more versatile than SKYPATROL but shareware as opposed to SKYPATROL which appears to be freeware)- Im a great supporter of freeware :-)) Another point "against" UFOCapture is that the manual is in Japanese - something I dont plan to learn. (9) Sorry this is so long - I feel its worthwhile "publishing" such so that other video observers may find it useful - in fact ANY video camera sensitive enough to spot satellites will find this technique useful. Cheers Greg ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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