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From: klewis@mwunix.mitre.org (Keith Lewis)
Newsgroups: sci.military
Subject: Re: Tomahawks
Keywords: sun angle summer winter
Message-ID: <1991Jan25.034325.12952@cbnews.att.com>
Date: 25 Jan 91 03:43:25 GMT
References: <1991Jan18.005043.9622@cbnews.att.com> <1991Jan24.033445.19610@cbnews.att.com>
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From: klewis@mwunix.mitre.org (Keith Lewis)
In article <1991Jan24.033445.19610@cbnews.att.com> IO00672%MAINE.BITNET@VM1.gatech.edu (Sloth) writes:
>Jon C. R. Bennett writes:
...
>>Fransico Bay) was created from 2D Landsat data by having a computer
>>compare the shadows cast by the sun at different times of the day. It is
...

>The Landsat satellites run in a sun-synchronous orbit. That is, the
>orbital plane is such that it precesses across the Earth at the same
>rate as the Earth's rotation. Thus, no matter where the images are taken,
>they all are taken at the same local time (nominally 9.30a) and have the
>same "sun angle."

You could make it so that the satellite passes over the same area at the
same time every day, but that will only stabilize the longitudinal 
componant of "sun angle."  The latitudinal componant will still vary with 
the seasons.  

In other words, you only get repeats twice a year.

--
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Keith Lewis		klewis@mwunix.mitre.org, klewis@mitre.org
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