On Sunday 20 October 1996, Ala' Shahin wrote: > > I have downloaded Quicksat but I guess I am having > some troubles making it work right. > > In most cases I get Tim value of 29.9 .... > I don't know what is wrong ... it is supposed that > the element file is fresh. > Can anyone tell me what is wrong? > > The problem is that the element file is NOT fresh; Quicksat includes in its results a column called "Dys" which is, essentially, how many days old that satellite's elements are. For example, in your sample: > > *** 1996 Oct 20 Sun evening *** Times are PM CDT *** 1829 547 > > H M S Tim Al Azi C Dir Mag Dys F Hgt Shd Rng EW Phs R A Dec > > 20322 CoBE 4.9 8.5 16 2.5 4.5 > 7 8 5 29.9 24 47 255 6.32287 0 526 34 1047 .8 38 238 47.9 this line has a Dys value of 287, meaning that the elemtents are over 9 months old. Quicksat's estimate of time uncertainty ("Tim") is, as you noted, "29.9" minutes, a not-unreasonable value for such "old" elements; in fact, the "real" value may be much larger. I believe Mike McCants prints out "29.9" for any prediction for which that quantity is equal or greater than that value. Running your control file information against tle.885, a recent elements file, produces, for example: 32.000 36.000 2450. AMMAN, JORDAN 2000 8.0 15 F F T T T *** 1996 Oct 20 Sun evening *** Times are PM CDT *** 1829 547 H M S Tim Al Azi C Dir Mag Dys F Hgt Shd Rng EW Phs R A Dec 20322 CoBE 4.9 8.5 18 2.5 4.5 6 34 3 .0 52 167 4 5.4 4 0 547 464 671 1.5 76 2041 -5.5 6 35 31 .0 89 261 C 95 4.9 4 0 546 470 547 1.8 79 20 7 31.7 6 37 0 .0 52 346 175 5.5 4 0 546 476 671 1.3 86 1837 67.4 In this case, the elements for this object are just four days old. Clear and dark skies! Ed Light Lakewood, NJ, USA N 40.1072, W 074.2317, Hgt +21m