Ang: LEO satellite tracking with a Meade telescope

From: b_gimle@algonet.se
Date: Wed Dec 15 2004 - 16:33:08 EST

  • Next message: Andy Kirkham: "RE: LEO satellite tracking with a Meade telescope"

    I downloaded the most recent update a few weeks ago (probably the same)
    The biggest bonus is the three-star alignment, but sat tracking still fails.
    
    Not the glorious ways yours did, but that has happened to me even on star alignment.
    After that, I got my Autostar replaced, and although I used it mostly like 
    a Dobson
    (hand-operated) I am reasonably confident there was some hardware error 
    on the first one.
    
    On both programs versions I have tested a small ACP program (modified the 
    demo program
    that comes with Starry Sky/ACP and the comnnection cable. It seems to position 
    correctly,
    but apart from scope slew, there seems to be a delay of almost two seconds 
    for a
    position read/write.
    
    This modified program logs the time and position each time I press spacebar, followed 
    by an optional comment.
    
    Using this while Autostar purportedly follows a satellite, I noticed a 1-
    6 degree pointing error,
    plus stopping tracking high in the sky, without any tripod leg problem. 
    This is for both versions.
    
    I haven't felt like reporting this widely yet, because like yours my tests are 
    infrequent.
    The fact that I have to bring the tripod, mount, Autostar and computer 
    together
    (in our summer house) just to test the programming is no help either!
    
    Presently I intend to use text output from a graphic prediction program, like 
    SkyMap 
    or ObsReduce, selecting good reference stars, and uploading these positions 
    as
    User Objects to the Autostar, and/or connecting the laptop directly and let 
    the laptop
    move the scope to the next available (pre-selected) position when I press 
    some key.
    
    This could also compensate for Earth's rotation when an object is early/late, which
    probably no generally available control program does !?
    
    /Björn
    
    
    >----Ursprungligt meddelande----
    >Från: thomasfly@j2ee-consultants.com
    >Datum: Dec 15, 2004 9:03:27 PM
    >Till: SeeSat-L <SeeSat-L@satobs.org>
    >Ärende: LEO satellite tracking with a Meade telescope
    >
    >In prior (not very recent) attempts to track the ISS with my Meade LXD55 scope, 
    it failed miserably, "tracking" into the
    >ground, rather than the sky.
    >
    >I'd downloaded the Java serial I/O library, and had been playing with issuing 
    Autostar commands, using a simple demo
    >program that comes with that library, when I discovered an update to the 
    firmware (Autostar model #497 version 33Ef,
    >12/6/04):
    >http://www.meade.com/support/auto.html
    >
    >In testing with TLEs for a couple recent ISS passes, the new version appears 
    basically to work (though I can't easily
    >determine how accurately); though in both cases, it stopped tracking when 
    it appeared that further tracking would cause
    >the OTA to smack into the tripod (there doesn't seem to be a way to choose 
    which of the 2 possible sections- separated
    >by a tripod collision- of a pass to track).
    >
    >That problem had occurred to me, in thinking about how to implement my 
    own tracking software.  One way to give the
    >telescope free reign over the sky would be to effectively convert the 
    equatorial mount to an altitude-azimuth mount, by
    >mounting it to a post, with the RA axis vertical.  However, passes near 
    the zenith would require a high rate of RA slew,
    >during which the satellite might be lost (at least temporarily).
    >
    >Alternatively, one could have a pseudo altitude-azimuth arrangement, by 
    making the RA axis horizontal, and (most simply)
    >parallel or perpendicular to the path of the satellite.
    >
    >Just using a post mount, rather than the tripod, would mitigate the tripod 
    collision problem, of course.
    >
    >I'd be interested in hearing about any existing solution to this problem, as 
    well as any successes people may have had
    >using Autostar.
    >
    >-------------------------------------------------------------------------
    >Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    >http://www.satobs.org/seesat/seesatindex.html
    >
    >
    
    
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Wed Dec 15 2004 - 16:48:01 EST