RE: Request by Charles David Phillips

From: Björn Gimle via Seesat-l <>
Date: Tue, 24 Jan 2017 11:00:16 +0100
Charles posted an observation project in the restricted "So you want to see
satellites" Facebook group. It relates to possible future breakups of DMSP

He included a map showing one position and a rather dim partial track.

Using a recent feature at Heavens-Above I extended it to show full world
tracks, with extent of surface darkness, and sunlight and shadow along the

This was made as three images for 02:24 UTC Jan 24 to have surface darkness.
I combined them with PaintShop Pro ("Lightest")

The tracks are drawn true to the topography. So when F15 passes e.g. South
African latitude (moving southbound) some 15 minutes after the predicted
position, the distance from F15 to the morning terminator will be about
four degrees shorter, and F16 track some 15 minutes before prediction is
four degrees (400 km) further away as it passed near Cape Town. F17 will
only be in the E during dawn.

Chris Peat  described the mapping feature :
"I also added a time parameter to make it easier for you. If you use this
URL, you can modify the "mjd" parameter,
which stands for the Modified Julian Day number.
Today  (2016-03-14 midnight UTC) is 57461.0

You could also adjust the size using the width and height parameters.
(Use same aspect ratio !)

The mode parameter controls the view. Possible values are;
A - above satellite   (aspect ratio 1:1)
M - map (ground track over rectangular Earth map) (1:2)
N - above orbital plane (1:1)  "
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Received on Tue Jan 24 2017 - 04:00:55 UTC

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