NavList:

Modris,
I am impressed by your thorough analysis of the Vega lunar observation, and I agree with your conclusions. In my enclosed solution, I didn't start with an assumed longitude but with an assumed GMT, which is the same thing. I thought I should be careful and tried to calculate the altitudes as accurate as possible, ending up in some iterations going from true to apparent altitudes. Your solution is much more elegant: first compute a rough apparent altitude, accurate within a minute of arc or so, and then compute the true altitude with all necessary corrections included. It is much easier to go from apparent to true as all tables are designed for this.

Anyway, both our results are very close to Vega's, which is given at the end of my paper. I do not know how they performed their calculations, have only seen their final result. The longitude determined for their winter quarter was taken as the mean value of six occultations together with this lunar, but there were quite a spread within these observations: 58 seconds of time.
Lars