Correction of LAT (Local Apparent Time - Sun-Dial)
to LMT (Local Mean Time)
LAT (sundial time) was used prior to the late 1700s. Geneva switched
from LAT to LMT in 1780; London in 1792; Paris in 1816: Norway in 1834;
Sweden in 1841; Switzerland in 1851.. (Arthur Blackwell). GMT was used for
95% of public clocks in Britain by 1855, even though GMT did not become
the official legal time for all of Britain until January 1, 1880. (David
Fisher, Time Changes in Great Britain)
Equation of Time
(Calculated for 12 UT daily for the year 1700)
| |
Jan. |
Feb. |
Mar. |
Apr. |
May |
Jun. |
Jul. |
Aug. |
Sep. |
Oct. |
Nov. |
Dec. |
|
| 1 |
+4:24 |
+14:17 |
+12.45 |
+3:55 |
-3:13 |
-2:48 |
+3:08 |
+5:43 |
-0:22 |
-10:26 |
-16:10 |
-10:23 |
1 |
| 2 |
+4:52 |
+14:24 |
+12:33 |
+3:37 |
-3:21 |
-2:39 |
+3:19 |
+5:40 |
-0:41 |
-10:44 |
-16:10 |
-9:59 |
2 |
| 3 |
+5:20 |
+14:30 |
+12:19 |
+3:18 |
-3:28 |
-2:30 |
+3:30 |
+5:35 |
-1:00 |
-11:03 |
-16:10 |
-9:35 |
3 |
| 4 |
+5:47 |
+14:35 |
+12:06 |
+3:00 |
-3:25 |
-2:20 |
+3:41 |
+5:30 |
-1:19 |
-11:21 |
-16:09 |
-9:11 |
4 |
| 5 |
+6:14 |
+14:39 |
+11:52 |
+2:42 |
-3:41 |
-2:10 |
+3:51 |
+5:25 |
-1:38 |
-11:38 |
-16:06 |
-8:46 |
5 |
| 6 |
+6:40 |
+14:43 |
+11:37 |
+2:24 |
-3:46 |
-2:00 |
+4:02 |
+5:19 |
-1:58 |
-11:55 |
-16:04 |
-8:20 |
6 |
| 7 |
+7:06 |
+14:46 |
+11:22 |
+2:06 |
-3:51 |
-1:49 |
+4:12 |
+5:12 |
-2:18 |
-12:12 |
-16:00 |
-7:53 |
7 |
| 8 |
+7:31 |
+14:48 |
+11:07 |
+1:49 |
-3:55 |
-1:38 |
+4:21 |
+5:05 |
-2:38 |
-12:28 |
-15:55 |
-7:27 |
8 |
| 9 |
+7:56 |
+14:49 |
+10:51 |
+1:31 |
-3:59 |
-1:27 |
+4:30 |
+4:57 |
-2:58 |
-12:44 |
-15:50 |
-6:59 |
9 |
| 10 |
+8:20 |
+14:59 |
+10:35 |
+1:15 |
-4:02 |
-1:15 |
+4:39 |
+4:49 |
-3:19 |
-13:00 |
-15:43 |
-6:32 |
10 |
| 11 |
+8:44 |
+14:49 |
+10:19 |
+0:58 |
-4:04 |
-1:04 |
+4:47 |
+4:40 |
-3:39 |
-13:15 |
-15:36 |
-6:04 |
11 |
| 12 |
+9:07 |
+14:48 |
+10:02 |
+0:42 |
-4:06 |
-0:51 |
+4:55 |
+4:30 |
-4:00 |
-13:29 |
-15:28 |
-5:35 |
12 |
| 13 |
+9:30 |
+14:47 |
+9:45 |
+0:25 |
-4:08 |
-0:39 |
+5:03 |
+4:20 |
-4:20 |
-13:43 |
-15:19 |
-5:06 |
13 |
|
14
|
+9:52
|
+14:44
|
+9:28
|
+0:10
|
-4:08
|
-0:27
|
+5:10
|
+4:10
|
-4:41
|
-13:56
|
-15:09
|
-4:37
|
14
|
|
15
|
+10:13
|
+14:41
|
+9:10
|
-0:06
|
-4:08
|
-0:14
|
+5:16
|
+3:59
|
-5:02
|
-14:09
|
-14:59
|
-4:08
|
15
|
|
16
|
+10:33
|
+14:37
|
+8:53
|
-0:20
|
-4:08
|
-0:01
|
+5:23
|
+3:47
|
-5:22
|
-14:22
|
-14:47
|
-3:39
|
16
|
|
17
|
+10:53
|
+14:32
|
+8:35
|
-0:35
|
-4:09
|
+0:12
|
+5:28
|
+3:35
|
-5:43
|
-14:33
|
-14:35
|
-3:09
|
17
|
|
18
|
+11:12
|
+14:27
|
+8:17
|
-0:49
|
-4:05
|
+0:25
|
+5:33
|
+3:22
|
-6:04
|
-14:44
|
-14:22
|
-2:39
|
18
|
|
19
|
+11:31
|
+14:21
|
+7:59
|
-1:03
|
-4:03
|
+0:38
|
+5:38
|
+3:09
|
-6:25
|
-14:55
|
-14:08
|
-2:09
|
19
|
|
20
|
+11:48
|
+14:14
|
+7:40
|
-1:16
|
-4:00
|
+0:51
|
+5:42
|
+2:56
|
-6:46
|
-15:05
|
-13:54
|
-1:39
|
20
|
|
21
|
+12:05
|
+14:07
|
+7:22
|
-1:29
|
-3:57
|
+1:04
|
+5:45
|
+2:41
|
-7:06
|
-15:14
|
-13:38
|
-1:09
|
21
|
|
22
|
+12:21
|
+13:59
|
+7:03
|
-1:42
|
-3:53
|
+1:17
|
+5:48
|
+2:27
|
-7:27
|
-15:23
|
-13:22
|
-0:39
|
22
|
|
23
|
+12:37
|
+13:50
|
+6:45
|
-1:54
|
-3:49
|
+1:29
|
+5:50
|
+2:12
|
-7:47
|
-15:31
|
-13:05
|
-0:09
|
23
|
|
24
|
+12:51
|
+13:41
|
+6:26
|
-2:06
|
-3:44
|
+1:42
|
+5:52
|
+1:56
|
-8:08
|
-15:38
|
-12:47
|
+0:21
|
24
|
|
25
|
+13:05
|
+13:31
|
+6:07
|
-2:17
|
-3:39
|
+1:55
|
+5:53
|
+1:40
|
-8:28
|
-15:45
|
-12:29
|
+0:51
|
25
|
|
26
|
+13:17
|
+13:20
|
+5:48
|
-2:27
|
-3:33
|
+2:08
|
+5:53
|
+1:24
|
-8:48
|
-15:50
|
-12:10
|
+1:21
|
26
|
|
27
|
+13:29
|
+13:09
|
+5:29
|
-2:38
|
-3:26
|
+2:20
|
+5:53
|
+1:07
|
-9:08
|
-15:56
|
-11:50
|
+1:51
|
27
|
|
28
|
+13:41
|
+12:58
|
+5:10
|
-2:47
|
-3:20
|
+2:32
|
+5:52
|
+0:50
|
-9:28
|
-16:00
|
-11:29
|
+2:20
|
28
|
|
29
|
+13:51
|
|
+4:52
|
-2:57
|
-3:12
|
+2:44
|
+5:51
|
+0:32
|
-9:47
|
-16:04
|
-11:08
|
+2:49
|
29
|
|
30
|
+14:00
|
|
+4:33
|
-3:05
|
-3:05
|
+2:56
|
+5:49
|
+0:15
|
-10:07
|
-16:06
|
-10:45
|
+3:19
|
30
|
|
31
|
+14:09
|
|
+4:14
|
|
-2:57
|
|
+5:47
|
-0:04
|
|
-16:09
|
|
+3:47
|
31
|
|
