NavList:

   

Reply

>
>|
>| >When discussing lunars and their accuracies, list members should be
>careful
>| >to state whether they are discussing / observing lunars taken at sea or
>| >lunars measured from on land. There are  significant differences.
>| >
>| >George.
>|
>| Are the differences in accuracy just due to the fact that lunars at sea
>are
>| taken from a platform that is not completely stable George? Or is there
>| something else involved?
>|
>| Geoffrey Kolbe
>
>No, I had nothing else in mind, other than that instability, and the
>difficulties it causes in achieving the necessary precision. .
>
>George.

My experience in doing lunars is limited on land and zero at sea. But my
impression is that the main difficulty is holding the sextant at a
more-or-less horizontal angle which, because it was not designed to be so
held, leads quickly to a rapid 'tremor' due to muscle fatigue. At sea, on a
vessel whose weight is four figures of tons rather than yachts, which bob
about with only single figures in tons, I would have thought the slow
movement of the vessel (in reasonable seas) would have been much less of a
problem and so contribute much less to the errors of the measurement than
the fatigue of holding a heavy, unwieldy instrument.

Comments, anyone...?

Geoffrey Kolbe


--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply