NavList:

Celestial Running fixes are as you describe (Terrestial Running fixes are a different matter altogether) which is to say several LOP's advanced or retarded over a span of several hours.  I would tend to agree that the LAN sun and Moon lines (both shot within a minute) crossed would constitute a fix by themselves, while the AM sunline advanced to noon would be considered a checking LOP that would be more questionable due to the effects of set and drift on its advance.

 

However, there is a catch here.  The sun and moon lines were shot at about 12:20 LT and we are looking for a 1200 position for the noon slip and to calculate the "day's run."  Therefore, both of these lines must be retarded 19 and 20 minutes respectively to give us a 1200 position which, along with the advanced AM sunline, give us a 1200 Running fix. 

 

The general practice in the US system is to advance any number of AM sunlines to noon and advance or retard LAN to noon to give us the 1200 running fix.  This position is thought of as a bit questionable, and often times the DR lines are run from AM stars to PM stars without correction by the noon position, although I am sure there is a lot of variation due to the Captain's preference.

 

Jeremy

 

Jeremy,
I've just worked the first part of the exercise, but I got to a slightly
different result.
In fact I use to define a running fix one which is derived from observations
well spaced in time, e.g. a couple of hours before LAN, LAN and a couple of
hours after LAN: in this case I assume the center of the (hopefully) small
triangle formed by these three LOPs as being the Fix. In this case only one
LOP is really spaced in time, i.e. the sun LOP of the morning, while LAN and
moon LOP are only a few minutes apart, so I would rely on the latters to
calculate the 1200 fix which is then 15deg 13.7' N 145deg 00.0' E.
What do you think?
Federico