NavList:

   

Reply

Douglas Denny has missed the point. The nearness of his observation point to
Greenwich has nothing to do with it. The time correction, due to changing
declination, as the same the whole world over, at the same latitude and
time-of-year..

His calculated time of Meridian Passage may well be correct. But he isn't
observing Meridian Passage, when the Sun is due South. He is observing
maximum altitude, the peak of the curve, which is subtly different.

George.

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
----- Original Message -----
From: 
To: 
Sent: Friday, September 25, 2009 11:48 PM
Subject: [NavList 9933] Re: Time of meridian passage accuracy



I wrote:-

"You will also note from the graph of my example, that the maximum altitude
was
within one minute of arc for approx plus and minus ten minutes of time. This
is the main point in question here I believe - that obtaining Mer passage at
the location to within one minute of time using an Equation of Time within
this limit is  _more_  than adequate".

---------

I should have also mentioned you will note from the graph that Mer passage
at Bosham is exactly as calculated coinciding with the peak of the curve,
because I calculated the declination at the exact time for Greenwich Mer
passage for the day and time, and also calculated Equation of Time for that
time exactly too.

I could have further calculated for the exact time for the Mer Passage at
Bosham - but as mentioned - negligable difference so did not bother.  I
might have done so if I lived, like Bill,  in New Zealand.


Douglas Denny.
Chichester. England.




--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply