At 11:38 AM on 7 Sep 97, Bruce LeGrande said to Tom DelFratte:
BL> Tom DelFratte wrote in a message to All:
Ahh, you're in EDT at the moment; let me fix something for you:
Converting between 12-hour time and 24-hour time:
     
12h 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11
24h 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23
 midnite                               noon                            
dnite
(There can be long arguments about whether Midnight is 2400 or 0000; it is
agreed, however, that 1200 is Noon.)
- = - 
American Standard Time Zone Names and hour offsets from UCT (GMT):
Atlantic Eastern Central Mountain Pacific Alaska HawaiiAleutian Samoa Wake 
Guam
  -4       -5      -6       -7      -8      -9       -10          -11  +12  
+10
(Note that the International Date Line lies between Samoa and Wake, and those
times are ahead of UCT/GMT.)
(new name) Universal Coordinated Time = Greenwich Mean Time (old name)
Given that it is some time hhmm UCT, the time in the other zone is 
the sum of hh and the offset, where the offset is understood to be
a signed number.  For most of the USA this means that we end up 
subtracting (adding a negative.)  Note that not all of the places
in the world have such simple offsets; parts of Australia, for example
have an offset of some number of hours and thirty minutes.  And some 
areas have offsets that are even smaller intervals (I think they're
all on five minute boundaries, now, though, if not quarter-hour!) 
The chart below I use when I'm yawning.  Not that I'm too much good at
arithmetic anyway, I've been spoiled by calculators and multi-zone watches.
UCT 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23
+1  01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00
+2  02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01
+3  03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02
+4  04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03
+5  05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04
+6  06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05
+7  07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06
+8  08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07
+9  09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08
+10 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09
+11 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10
+12 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11
-11 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12
-10 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13
-9  15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14
PST 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
MST 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 
PDT
CST 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 
MDT
12h  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5 
CST
                     = = = = = = = = = AM = = = = = = = =
12h  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6 
CDT
EST 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 
CDT
12h  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6 
EST
                  = = = = = = = AM = = = = = = = = = =
12h  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7 
EDT
AST 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 
EDT
-3  21 22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 
ADT
-2  22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21
-1  23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22
UCT 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 
UCT
12h 12  1  2  3  4  5  6  7  8  9 10 11 12  1  2  3  4  5  6  7  8  9 10 11
     = = = = = = = = = AM = = = = = = = = - - - - - - - - - PM - - - - - - -
The bar inserted into the grid between my time zones (you can of course move 
it
to yours, adjusting the numbers by circularly shifting them to fit your zone)
has the 12-24, normal-summer, and local-UCT conversions done; enter the 
ottom
of the grid with 1156 UCT, read up and find 6:56 AM CDT or 5:56 AM CST.  Or 
enter the grid at 2000 CST, read down to find 8 PM CST, 9PM CDT, and 0200 UCT
the following day.
(I've inserted an additional bar for EST-EDT; note that EST=CDT.  You'll want
to delete the five lines between CST and EST.)
Enter the bottom UCT bar, move to the right to 15xx, up to EDT, find 11xx, 
nd
up again finding 11:xx AM EDT, or 10:xx EST.  
If you cross the 00 marking, you've changed days, forward or backward.
Happy listening!
-=- htom@spare.tdkt.org -=- Neither a lawyer nor a LEO and not on TV. -=-
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