# Mir and the good old days

From: Randy John (skysat@home.com)
Date: Thu Mar 22 2001 - 23:18:25 PST

• Next message: Antonín Vítek: "Re: Mir re-entry video very good!"

```As long as we are reminiscing about Mir I thought I would tell you how I did
it in the "good old days".

When I first got started observing satellites I would just go outside and
look.  Of course I had heard of Mir but hadn't actually seen it (at least
not to my knowledge).  Eventually I found out that you could call the
National Space Society (now they have a website, http://www.nss.org/) and
they would give you predictions for the nearest large city.  While talking
to the person on the phone I was told that in addition to the predictions
they also had elements.  "Let me have them", I said.  Of course I wasn't
quite sure what to do with them now that I had them, but I persevered.

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 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).

So the next time you complain that heavens-above is too slow - just do it
the old fashioned way.

ISS is certainly nice, but there will never be another Mir.

Randy

p.s.  I still have the globe.  The string is still wrapped around the base.

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