questions and comments on http://tycho.usno.navy.mil/tzones.html

[Paul Eggert]

Thanks for putting the USNO unofficial time zone info on the Web; it
has helped me compose proposed patches for the public domain time
zone history database at <ftp://elsie.nci.nih.gov/pub/tzdata95k.tar.gz>.

After comparing the USNO data to other sources, I have some questions
and comments.  I'd appreciate any information you can send me to clear
up the questions, especially pointers to other sources.  The tzdata
history database relies heavily on Thomas G. Shanks, The International
Atlas (3rd edition), San Diego: ACS Publications (1991), a source that
is now 4 years old, so some of the discrepancies noted below are
undoubtedly because the time zones or daylight savings rules have
changed recently.  But I thought I'd tell you about the discrepancies
just in case.

<http://tycho.usno.navy.mil/tzones.html> (1995-11-11) says:


	Antarctica: -2 hours (Local summer -3 hours)

Which part of Antarctica is that?  I have the vague impression that
different research stations in Antarctica use different local times.
(The South Pole is the most interesting case, of course.)


	Armenia: +4 hours (Local summer +5 hours)

Shanks has Armenia switching to +3 (+4 summer) in 1991.
Perhaps they've switched back?


	Argentina western prov: -4 hours 

Shanks says Argentina has always had just one time zone.


	Azerbajian: +3 hours 

Shanks has Baku at +3 (+4 summer).
Perhaps they've stopped using daylight savings time?


	Brazil Acre: -4 hours (Local summer -5 hours)
	Brazil Atlantic Islands: -1 hours (Local summer -2 hours)
	Brazil East: -3 hours (Local summer -1 hours)

These must be typos.  Here are proposed fixes.

Brazil Acre: -5 hours (Local summer -4 hours)
Brazil Atlantic Islands: -2 hours (Local summer -1 hours)
Brazil East: -3 hours (Local summer -2 hours)


	Chatham Island: +12.75 hours (Local summer +13.75 hours)

Do you have a source for when the transition to and from summer time
takes place?


	Cocos (Keeling) Islands: ( hours (Local summer ) hours)

This is a typo.  The 1989 USNO listing has Cocos at +6.5 hours.


	Cook Islands: -10 hours 

Shanks has Cook at -9.5 during summer.  The 1989 USNO listing had two entries
for Cook, one at -10, the other at -10 (-9.5 summer) like Shanks.


	Equitorial Guinea: +1 hours 

This should be `Equatorial Guinea'.


	French Polynesia: -10 hours 

French Polynesia covers several time zones; e.g. I think the Marquesas
and Gambier are part of French Polynesia, and they are at -9.5 and -9,
respectively.


	Georgia: +4 hours 

Shanks says Georgia has summer time, but this may have changed with
the rules change late last year (see _The Economist_, 1994-11-19, page 60).
Is there a better source for this?


	Greenland Scoresbysun: -1 hours (Local summer 0 hours)

This should be `Scoresbysund'.


	Guinea Bissau: - hours (Local summer 0 hours)

This should be `0 hours', with no summer time.


	Kazakhstan: +6 hours (Local summer +7 hours)

Shanks says Alma-Ata switched to +5 (+6 summer) in 1991.
Perhaps they've switched back?


	Kiribati: +12 hours

The country of Kiribati covers several time zones.
Perhaps you could change `Kiribati' to `Tarawa'.


	Kwajalein: -12 hours

In comp.risks 14.87 <http://catless.ncl.ac.uk/Risks/14.87.html#subj2>
(1993-08-26), Peter Neumann writes that Kwajalein changed to +12 hours
on 1993-08-20.


	Libya: +2 hours

Shanks has Libya at +1 (summer +2).


	Mexico Baja Calif Norte: -8 hours (Local summer -7 hours)

Shanks has Ensenada, southern Baja, at -8 all year.


	Mongolia: +8 hours

Shanks says Mongolia has 3 time zones: +7 (+8 summer), +8 (+9 summer),
and +9 (+10 summer).


	Namibia: +1 hours (Local summer +2 hours)
	Nicaragua: -6 hours (Local summer -5 hours)

Shanks has Namibia at +2 all year, and Nicaragua at -6 all year.
If these have changed recently, do you know when it changed, and what
the transition times are?


	Russian Federation zone two: +4 hours (Local summer +5 hours)

This must be a typo; it should be `+3 hours (Local summer +4 hours)'.


	Scotland: 0 hours

Shanks and other sources have Scotland at +1 in summer.


	Tajikistan: +6 hours

Shanks has Tajikistan at +5 (+6 summer).
Perhaps they've switched?


	Tunisia: +1 hours

Shanks has Tunisia at +2 in summer.
Perhaps they've stopped using DST?


	Turkmenistan: +5 hours

Shanks has Turkmenistan at +6 during summer.
Perhaps they've stopped using DST?


	Ukraine: +2 hours (Local summer +3 hours)

Ukraine has multiple time zones.  _The Economist_ (1994-05-28, page
45) reports that Crimea switched to +3 (summer +4) last year.


	Uzbekistan: +5 hours

Shanks has Tashkent at +5 (+6 summer).
Perhaps they've stopped using daylight savings time?