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» Online Classroom   » Emergency Navigation   » Public Discussion of Emergency Navigation   » "Stars do not move faster than 15°/hr"

   
Author Topic: "Stars do not move faster than 15°/hr"
Michael Orton


 - posted March 27, 2005 01:16 PM      Profile for Michael Orton           Edit/Delete Post 
At first I took this to mean at the equator such as Mintaka and the
Orion System and concluded that stars at 40S or 40N might then move at
10 deg per hour on up to Polaris which moves not at all.

I then thought about the curve taken by the sun and stars, either to
the North or the South and the greater distance necessarily involved.


This led to the question: "Do stars also have 'great circle' routes
and if so would the 15 deg. per hour maximum rule still apply?

Mayhap the participants can tackle this one. The answer may be easy
or hard but since dawn is approaching at 7S 20W I'll leave it for
another night watch or a later chapter in the Celestial Course.

David Burch


 - posted March 27, 2005 01:24 PM      Profile for David Burch           Edit/Delete Post 
You are right, or the quote is right, which can also be expressed in arc min/min, which is what we see in the sextant.

stars do not move faster than 15'/1m along any arc in the sky ... can be slower in height change rel to horizon but for bearing can be slower or faster! relative to some reference scheme on the horizon.

we leave the latter thought as a point for discussion.

From: Starpath, Seattle, WA


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