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Norm, you wrote:
"Castor and Pollux too. Lots of data for Lunars? Can you find a lunar distance accurately with a full moon?"

There's one small catch with a not quite full moon. One might measure a distance to the edge that isn't quite full. That, of course, would lead to a little error. But otherwise, a full moon is fine. It's awfully bright, but sextants were designed with lots of shades in both viewing directions just for this purpose. When we look at actual practice, as seen in many historical logbooks, full moons were rarely used for lunars because the Sun was, by far, the prefered "other body" in lunars, and the period right around First Quarter or Last Quarter was the prefered period for shooting lunars.

Jupiter right at this moment, though very pretty, is in the worst position for traditional lunars (for finding GMT and from that longitude). If you look at the real moon or a simulation of it, you'll find that Jupiter is lined up almost perfectly with the north pole of the Moon. The Moon's motion across the celestial sphere is just about perpendicular to that, so the Moon-Jupiter arc is nearly unchanging with time in this geometry. Among the standard lunars stars, that also rules out Pollux, but Regulus and Aldebaran are nicely aligned along the Moon's path, ahead and behind respectively. A very careful lunarian historically might have done a set with three or four Pollux lunars and three or four Aldebaran lunars to cancel out some sources of error by shooting on opposite sides of the Moon.

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