Various observers at various times have reported observations of STS orbiters at widely varying magnitudes (after accounting for range, formal phase angle (as in QuickSat), and meteorological conditions) during all of the following: 1) on successive passes 2) at different times during the same pass -and- 3) from different locations during the same pass. If you glance at an orbiter, you immmediately see that this can happen because of its: 1) varying albedo presented by the combination of shiny payload doors, white tile and black tile -and- 2) convoluted, boxy, shadowy, concave/convex shape. Similar, if somewhat less extreme, considerations apply to Mir for similar reasons. Dan Laszlo writes: > However, on the previous STS-Mir mission, within a few hours of > separation, Mir was clearly ahead of the Shuttle when it made its pass > for us in Colorado. and then: > I was primed to expect STS to lead, and I'll admit initial disbelief at > the sight, with a dimmer, yellow tinged object leading the brighter > white object. If by this you mean that the leading object clearly had to be Mir because it was dimmer than the trailing object, then I would have to be very skeptical, although I would agree that you have some justification for suggesting this. I've noticed other observers tend to pay more attention to color, something I am not particularly sensitive to. Perhaps they will comment. I would suggest that good elsets from the time you observed might be a more reliable source of an ID than magnitude. I really try to live by the maxim: Never throw out an elset. Even so, I'm not convinced the elsets I have are determinative. This is what I have which seems usable: Mir Complex post undocking jsc, http://sh...nasa.gov via Molczan, ele-rq 1 16609U 86017A 95322.45642709 .00003885 00000-0 46559-4 0 9179 2 16609 51.6410 104.9926 0002556 336.7720 23.3319 15.58152580557006 Mir ele-rq (i.e., Gary Morris) 1 16609U 86017A 95322.77713656 .00003885 00000-0 46559-4 0 9219 2 16609 51.6438 103.3888 0002558 336.7418 23.3621 15.58084095557058 Predicted Atlantis post undock jsc 1 23714U 95061A 95322.45640993 .00019322 00000-0 20677-3 0 9182 2 23714 51.6410 104.9925 0004889 328.8076 31.2788 15.58711072 948 If someone has superior elsets, particularly if they are accompanied by reasons for their superiority, please provide them. If not, there are a few repositories where we could look. Here is the corresponding QS output: 40.000 105.000 0. CO <---------------- 1950 9.5 4 F F F F F *** 1995 Nov 18 *** Times are UT *** 033 1255 H M S TIM AL AZI C U MAG REVS HGT SHD RNG EW PHS R A DEC 23714 STS-74 .1 12 43 4 .0 67 142 C 52 -.9 1.2 400 275 431 3.0 95 1028 21.2 16609 Mir Complex .1 12 43 8 .0 67 142 C 52 -.9 1.2 401 277 432 3.0 95 1028 21.4 12 43 10 .0 68 142 C 52 -.9 -3.8 401 277 432 3.0 95 1028 21.4 This does not seem exceptional. It follows the general rule imposed by energy considerations, that the shuttle trails while chasing Mir from a lower orbit, and leads after departing for a lower orbit. I would welcome additional insights. Cheers. Walter Nissen dk058@cleveland.freenet.edu --- Darkness has its place -- in the night sky. Look into it.