Hi everyone As Mike suggested below I have been using Tom Wagner's observation of the ISS transit of the moon to test the simulator. At first it predicted that the ISS would pass about 1 degree south of the moon just as Heavens Above did. Various other programs I looked at like Brent Bosharts SatTracker and Trackstar by Dr Kelso correctly predicted a pass across the moon. Eventually I worked out that the error was down to the calculation of the observers position. The problem is caused by using the observers geographical or geodetic latittude and not converting it to geocentric co-ordinates. At mid-latitudes that can result in an error of several degrees in the predicted RA DEC of a satellite. Once these corrections were in the simulator showed the ISS passing across the Moon. A good reference for the necessary corrections is http://celestrak.com/columns/index.shtml and OCS part III in particular Phil PS A new version of the ISS Simulator will be out soon including the Moon and greater acuracy of position and timing. ----- Original Message ----- From: "G6GAK - Mike Tyrrell" <g6gak@btinternet.com> To: "Philip Masding" <philip.masding@virgin.net> Sent: Monday, December 30, 2002 7:03 PM Subject: FW: ISS Transit Of Moon > You could use this as a test of your moon/ISS positions in the simulator... > > Mike > > -----Original Message----- > From: Tom Wagner [mailto:sciteach@mchsi.com] > Sent: 30 December 2002 04:28 > To: SeeSat > Subject: ISS Transit Of Moon > > > Hi all, > > A few days ago I got a surprise announcement from Kevin Fetter, a Canadian > SeeSat member. He politely informed me that, if I was interested, in a few > days the ISS was going to cross the center of the moon as seen along a line > a few km from my home. I more than gladly took up the challenge of dragging > myself out of bed this morning after 4 hours of fitful sleep. I took my > telescope and a digital-8 video camera (capable of 4 lux) along. The sky was > hazy but the moon was sharp as seen through my scope. At the time that Kevin > determined that the Station would pass it did, right where it was supposed > to! I could clearly see it cross both the dark AND sunlit parts of the moon > even though the Station itself was only a magnitude 1.6 (according to H-A ). > The moon was 23% illuminated and 25 degrees above the SE horizon. At 31x I > didn't detect any shape in the Station's image but I could tell that it was > a small extended object. > > I got the pass on video! Someday I'll get the time to make the video > available online. > > H-A as we discussed in earlier posts did not accurately place the track of > the Station across the moon. It showed it passing about 1 degree south of > it. Much thanks to Chris Peat all the same! > > The data I chose to use was as follows: 29 Dec 2002, 11:57:25.70, > 42.390, -92.318. That put me at the telescope at 5:57 AM out in a ditch in > the country. I'm glad the farm dog that started barking didn't come to take > a look. I've been bitten before. To decide where to go I input the > coordinates into http://www.topozone.com./finddd.asp . > > Thanks again Kevin! > > Clear skies, > > Tom > Iowa > USA > > At home: > Latitude: +42.473513 > Longitude -92.360413 > Meters above sea level: 274 > GMT -6 > ..... > > > > ----------------------------------------------------------------- > Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' > in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org > http://www.satellite.eu.org/seesat/seesatindex.html > > ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
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