Re: Mir and the good old days

From: Jonathan T Wojack (
Date: Tue Jun 26 2001 - 14:36:12 PDT

  • Next message: Randy John: "RE: Mir and the good old days"

    > So, what do you do with elements when you don't have a computer?  
    > You use a
    > 3 inch diameter globe (filled with pennies) and a piece of string of 
    > course.
    > The first thing that you do is hope that the eccentricity is close 
    > enough to
    > zero so that you can ignore it.  The only two numbers that are 
    > really
    > important are the inclination and the period.  Using a known pass, 
    > you lay
    > the string on the globe so that it passes through your site and has 
    > max/min
    > latitude the same as the inclination.  Now you can make future 
    > predictions
    > since you know where Mir will be in 15, 16, 30, 31, 46 or 47 orbits 
    > from
    > now.  During these passes the Earth will have rotated approximately 
    > 1, 2 or
    > 3 revolutions.  Of course, you had to make up for the difference 
    > between
    > "approximately 1 rev" and the actual amount of time.
    Using TLE data, I using a known H-A prediction for my site for SeaSat 1. 
    I used the data to project when the satellite would be visible 9 days
    later.  My prediction was only 4 minutes off the H-A prediction (which
    are almost always +/- 10 seconds that far into the future) !!!  So this
    works!  Thanks a lot for sharing this with us.
    > Using this method I successfully predicted a pass at my dark sky 
    > site more
    > than 150 miles away from the prediction city.  If you don't believe 
    > me, I
    > have a picture with Mir's trail about 5 degrees above the horizon to 
    > prove
    > it (I didn't actually see it).
    Randy, if you're listening, can you explain how to factor the inclination
    of the satellite into the calculations.  I don't see why it matters (for
    the sake of calculation) .  Also, is there a way to estimate the altitude
    of the satellite when observed (I understand how to determine in what
    area of the sky the satellite will "peak" in).
    Thanks very much!
    Jonathan T. Wojack       
    39.706d N   75.683d W           
    4 hours behind UT (-4)
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    This archive was generated by hypermail 2b29 : Tue Jun 26 2001 - 14:39:18 PDT