NavList:

There are, according to the clear explanation in the booklet RYA Astro Navigation by Tim Bartlett, at least three different conventions.

1) The conventional nautical system
Zones ahead of UT are designated as negative.
Zones behind UT are designated as positive.

2) The military system.
UT is designated Z.
Zones ahead of UT are designated from A to M (omitting J).
Zones behind UT are designated from N to Y.

3) The International Standards Organisation.
Zones ahead of UT are designated as positive.
Zones behind UT are designated as negative.

Remark 1)
I know who uses 1) and 2) but who uses 3)? Astronomers?

Remark 2)
Some years ago I had problems understanding the equation of time in old Astro Textbooks until I discovered that Brits and Yankees used opposite plus and minus designations. Nowadays they don't.

Remark 3)
I was tempted just to send a scan of the relevant page in Tim Bartlett's book to the list. Would that have been correct or would I have been stopped next time I tried to go to Britain and put in jail violating some publishing law?

Paul Werner
N59 E18

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