Re: Shuttle, ET, ISS and Iridium Flare

From: Jean-Paul Cornec (
Date: Sun Jun 01 2008 - 22:01:01 UTC

  • Next message: Russell Eberst: "2008MAY31.OBS"

    Last night I took a (very) bad picture of Shuttle-ET pass in twilight, 
    beneath Polaris. I could follow them for a longer time span than G. 
    Holtkamp. Following his interesting analysis, I found that, for me, the 
    apparent distance between Shuttle and ET was half the distance between two 
    stars of Cepheus (TYC 4650-3036-1 and TYC 4650-3037-1 ), that is 0.625. 
    Range of Shuttle and ET at closest approach was 275 km giving a distance of 
    3 km between them. Picture and stars can be seen at : . External Tank was 
    initially at m 3, and really red, when they appeared at about 10 elevation; 
    Shuttle was already at mag 0 to -1. But the brightness of ET increased 
    quickly at the same magnitude as Shuttle, and slightly but definitely 
    exceeding it. They kept their brightness until they entered shadow. They 
    were indeed about one magnitude less bright than ISS. They look pretty faint 
    on the picture but were really bright.
    What a lovely sight !
    Jean-Paul Cornec
    4844'20" N
    327'32" W
    ----- Original Message ----- 
    From: "Gerhard HOLTKAMP" <>
    To: <>
    Sent: Sunday, June 01, 2008 9:51 PM
    Subject: Re: Shuttle, ET, ISS and Iridium Flare
    > Checking the picture of the Shuttle / External Tank pass I took last night
    > with a fresh mind after a good sleep I get the following data:
    > The Shuttle passed Saturn (as viewed from my position) at a distance of 
    > 1.24
    > degrees which agrees with the NASA pre-launch elements (but the time of
    > 21:24:00 UTC, 31-MAY-08 was 5 seconds later than predicted). The apparent
    > angular distance of the Shuttle and the ET at that moment was 0.58 degrees
    > which (at a slant range of 395 km) would translate to a distance
    > (perpendicular to my line-of-sight) of 4 km. Comparing this picture with 
    > one
    > I had taken 10 minutes earlier of the ISS and a nearby Iridium flare I now
    > put the apparent brightness if the Shuttle to mag -2 (rather than mag -3 
    > as I
    > reported in my original message) but I keep the ET at mag 0 as stated
    > earlier.
    > Gerhard HOLTKAMP
    > Darmstadt, Germany
    > 49.8822 N, 8.6558 E
    >> Ten minutes later I could pick up the shuttle and the ET just a few 
    >> degrees
    >> above the horizon and follow them for over a minute until shadow ingress.
    >> The shuttle was about mag -3 with the distinctly red External Tank about
    >> half a degree below (still have to check my pictures to be sure for the
    >> distance) showing up at about mag 0 - maybe a little brighter. I timed 
    >> the
    >> passage of the two next to Saturn at 21:24:00 UTC, 31-MAY-08, which was 5
    >> seconds later than calculated with the NASA pre-planned elements. I also
    >> had the impression that the shuttle was passing a little higher above
    >> Saturn than calculated. Maybe they were inserted a little to high.
    > -------------------------------------------------------------------------
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