Re: 0 for 2 tracking ISS with Meade Autostar

From: Björn Gimle (b_gimle@algonet.se)
Date: Sun Nov 23 2003 - 10:03:19 EST

  • Next message: Thomas Fly: "Re: 0 for 2 tracking ISS with Meade Autostar"

    ----- Original Message ----- 
    From: "Thomas Fly"
    
    > An hour after sunset, under a superbly clear sky, the ISS made a stunning,
    > 69 degree elevation pass, which I tried to track with my 10" Meade
    > LXD55 Schmidt/Newtonian, after downloading the freshest McCants
    > TLE into the telescope's Autostar controller (I verified that it was
    > identical to the latest OIG TLE).  As with a lower elevation pass several
    > days ago, Autostar indicated an "AOS" about a minute later than the rise
    > time given in my NASA J-Pass email report.  The telescope basically
    > seemed to follow the path of the ISS, but delayed by that amount of
    > time- which is to say, it didn't work!
    
    I have a working version "0.1" of a program using the ACP ActiveX component
    running. It allows recording the performance of the Autostar satellite
    tracking program, as well as logging positioning to other objects, and your
    own manual tracking. Readout time approaches .5 seconds, so it will only be
    a help to identify the stars used for visual/video observation.
    
    Like you, I have tried a few passes and failed, but my Autostar later failed
    even on Easy Alignment, and I got a replacement a few weeks ago. I have had
    clouds, fog and rain since, so I have only made dry runs, which is what I
    recommend to you as well (set a fake telescope time close to rise time).
    (My) Autostar shows only AOS to the nearest minute, so that's no good
    verification, but look at the az/el of AOS and LOS, and verify that they
    match a trusted prediction program to the required precision. In my
    experience, most are 1-5 degrees off-track, so I'll have to write/find my
    own control program.
    For a pass that appears correct, GOTO the position well in advance, wait for
    the satellite to appear, and press ENTER. (obviously just theoretical
    knowledge).
    
    I'm afraid the existing program(s) do not take the Earth's rotation into
    account for an early/late arrival, which is why I was prepared to develop a
    program of my own for searching for decaying/maneouvred/debris objects along
    a complete orbit.
    
    /Björn
    
    
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