NavList:

J Hardy said,

>>Unless I am missing something here, it is a typical problem of longitude by chronometer.
The event is at 0233h UT, on August 28th. UT is UT, no daylight saving time.
The event is at 0133h, UT - 1, on August 28th, longitude 15 W
The event is at 0033h, UT - 2, on August 28th, longitude 30 W<<

I think this is EXACTLY what Frank Reed was getting at earlier. Zone time hides Local time. You can get zone time from your watch, and if you check the zone time of the event against the UT of the event, yes, you get a longitude of of a sort, but it's the longitude of the (effective!) time zone, which could be one hell of a long way from your real longitude.

If you're on Eastern Time (Quebec, JH?), then when you compare zone time against the UT of the start the lunar eclipse, you'll get a difference of four hours. THEREFORE (by your apparent reasoning above), yuor longitude is 60d West. Instead of Quebec, you're living in easternmost Nova Scotia OR Barbados. Every observer all across the Eastern Time Zone ends up with a longitude near Barbados. And THAT is why you can't use zone time for this. Zone time is a legally-decreed LOCKED offset from UT. It's got almost no info about lon in it. And btw even if we were not on EDT, we would still end up on a WRONG longitude, 75d instead of 60 West.

So how can you get local time? Or how can you do something equivalent?

For a completely modern case, I'll take a stab at it. On Thursday night, At the moment I am convinced that the Moon is beginning partial eclipse, which is only good to the nearest minute, I grab my sextant and shoot two stars with my artificial horizon (since it's not twilight). It's just two common sextant sights at known UT!!! You get a fix. End of story. But this version is strictly for moderns (not Ptolemy) and strictly for people like us in the NavList group who already possess the tools of celestial navigation. Still, that's all there is to it if you have a sextant. I think! The Moon event is like a digital clock up in the sky announcing the UT. We don't need to take sights off it. We don't care about the Moon except to see those eclipse events, each announcing some minute of UT

Josh