Hi all, In reference to item "c" below I have also found that Alan Pickup's site has the most reliably updated Iridium elsets. There is at least one other way to acquire very timely updates: I registered on the OIG website and copy a text file of the Iridium catalog numbers into the TLE query window. Now if we could just get a direct link from that radar "fence" in Texas... At 08:34 5/27/98 -0400, Walter Nissen wrote: > >> 1. Do you accurately know the latitude, longitude, and elevation data for >> your site? >> 2. Did you correctly enter this data into your prediction program? >> 3. Did you make a mistake when specifying your time zone? I use UTC for the >> date and time. >> 3. Are your Iridium orbital elements less than one week old? > >a. Did you enter your longitude with the correct sign? East is supposed >to be positive, but some older programs from the Western hemisphere may >use the old convention. If you are using more than one program, is it >correct everywhere? > >b. Did you confuse standard time and daylight time? UTC is pretty >convenient. I run my PC on UTC. > >c. These elsets are less than 1 week old: >Iridium 48 3.0 0.0 0.0 6.0 d 780 x 775 km >1 25107U 97082D 98146.24514426 .00015012 00000-0 53259-2 0 1231 >2 25107 86.3962 284.4531 0003838 66.7932 293.3651 14.34362860 22531 >Iridium 48 >1 25107U 97082D 98141.15255854 -.00003697 +00000-0 -12622-2 0 01588 >2 25107 086.4074 286.5779 0004213 070.0837 290.0753 14.36753424021801 >Yet this morning the culminations computed from them differ by almost 15 >minutes in time and 17 degrees in altitude. Ouch!! >And the frequently helpful TIM parameter in QuickSat required a >hair-trigger sensitivity, as it barely blipped. >The currently accurate, first, one is from Alan Pickup's file. The >second, I think, is from molczan.tle. > >Cheers. > >Walter Nissen dk058@cleveland.freenet.edu >-81.8637, 41.3735, 256m elevation > >--- > >Carpe noctem! > > Sincerely, Richard Fredrick rfredric@tfs.net Fairway, KS USA 39.021N 94.637W