Here is an update about the solar transit by the ISS I observed and successfully video taped on April 16, 2003 from a college campus here in NE Iowa. Coordinates I estimated from a topographic map service: 42d 25m 47s N 92d 19m 44s W altitude 900 feet (previously posted to SeeSat) Coordinates obtained from a GPS unit (after the event but used in making the final analysis): 42d 25m 50s N 92d 19m 40s W altitude 900 feet The TLE I used was obtained a couple hours before the event from CelesTrak at: http://www.celestrak.com/NORAD/elements/ : ISS (ZARYA) 1 25544U 98067A 03104.78447162 .00011195 00000-0 15207-3 0 8924 2 25544 51.6336 338.6980 0006712 19.3333 109.6182 15.58131185251116 The path of the ISS across the sun on my computer screen reaches about 19% into the solar disk. The path on my TV screen shows the pass cutting as far as 31% into the sun. Ralph McConahy's screenshot taken from SkyMap (using the NASA TLE below) showed the ISS cutting 31% into the sun, exactly as shown on my TV screen! The time prediction that Ralph got from his TLE (below) from the NASA ISS web site was ***17:35:57 UT***. ISS 1 25544U 98067A 03105.53106156 .00041100 00000-0 34010-3 0 9050 2 25544 51.6352 334.9570 0006812 21.4703 338.6736 15.58205811 11238 The time of entry predicted by the planetarium software I use called, "TheSky" was ***17:36:6.23 UT***. I used the coordinates I first sent to the group (same that Ralph used) and the CelesTrak TLE listed above. Actual time of 1st contact was close to ***17:36:05.5 UT***. I relied on my calling out times read off an atomic clock. It was slick! Several students were watching the image of the sun shown upon a brick building next to us and they too saw the ISS zip across the sun. It was very fast. I got it on digital tape. Clear skies, Tom Iowa USA ----- Original Message ----- From: "McConahy, Ralph" <RMcConahy@jgld.gdscc.nasa.gov> To: <SeeSat-L@satobs.org> Sent: Monday, April 14, 2003 5:09 PM Subject: RE: ISS solar transit on 4-15-03 > Using this TLE from the NASA ISS web site: > > ISS > 1 25544U 98067A 03105.53106156 .00041100 00000-0 34010-3 0 9050 > 2 25544 51.6352 334.9570 0006812 21.4703 338.6736 15.58205811 11238 > > The ISS will indeed cross the Sun's disk, but about 9-seconds earlier than > you predict (17:35:57 UT). > > Note that from your proposed location, the transit will not be through the > exact middle of the sun--for that you will need to move 0.67 miles to the > south. > > Ralph McConahy > 34.5489N 117.2205W 912m ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
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