[AZ-Observing] Re: Another Shuttle and ISS pass tonight (06/20)

Rick,

Wikipedia says the ISS' average speed is 17,240 mph, and I counted approx 14 
seconds for the ISS to catch up to the orbiter.

If you plug those numbers in the "distance = velocity x time" formula, like 
this:

17240 m/h
----------------      X   14 s
3600 s/h

You get 67 miles, and say +/- 10 miles.

True, I was counting, and not using a stopwatch, but we're still out by an 
order of magnitude on this one.

Do you know if SkyMap used predicted locations, or did it obtain get actual 
locations some how?

Heavens Above seemed to predict a separation of only one second, which would 
calculate out to around 5 miles.  Maybe SkyMap used similar TLE's as Heavens 
Above?

Neville


----Original Message Follows----
From: "Rick Tejera" <saguaroastro@xxxxxxx>
Reply-To: az-observing@xxxxxxxxxxxxx
To: <az-observing@xxxxxxxxxxxxx>
Subject: [AZ-Observing] Re: Another Shuttle and ISS pass tonight (06/20)
Date: Wed, 20 Jun 2007 22:18:12 -0700

Greg,

At 2200 they were 5.52 miles apart. OK, how'd I come up with that, you ask
(and I know someone will).

First I looked up their positions in SkyMap at 2200.

ISS: S 50 37 04, W 7 23 02
STS-117: S50 38 07, W 7 15 41

I then ran these coordinates in a utility I have call Forward/Inverse to
come up with the answer.

Now that being said this is a topographic solution, it would not take into
account the greater separation due to the higher altitude. I don't imagine
it would add up to much, but if anyone would like to do the trig, feel free.
:)


Clear Skies
Rick Tejera
President, Editor SACnews
Saguaro Astronomy Club
Phoenix, Arizona
www.saguaroastro.org
saguaroastro@xxxxxxx

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