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Determination of left/right boundaries

1. By using the sun

1.1 Left boundary on back wall


(Date: Dec. 21st, 1997)
 
 
Date start/end time tape start delay time event actual time center sun right side sun
15/12/97 14:31:49 00:00:20 00:10:09 14:42:18 214°58' 215°14'
15/12/97 15:16:49 00:00:00 -00:34:54 14:41:55 214°53' 215°9'
21/12/97 14:31:49 00:00:20 00:13:22 14:45:31 214°59' 215°15'
21/12/97 15:16:49 00:00:00 -00:30:42 14:46:07 215°6' 215°22'
The average sunset azimuth boundary (greenline, Line A) on left side off back wall is: 215°15' +/-5'
 

1.2 Right boundary on back wall


(Date: Jan 12th, 1998)
 
 
Date start/end time tape start delay time event actual time center sun left side sun
12/1/98 14:53:49 00:00:20 00:36:40 15:30:49 223°13' 222°57'
12/1/98 15:31:49 00:00:00 -00:01:12 15:30:37 223°11' 222°55'
17/1/98 15:07:49 00:00:19 00:23:01 15:30:50 223°16' 223°0'
17/1/98 15:46:49 00:00:00 -00:15:59 15:31:10 223°11' 222°55'
The average sunset azimuth boundary (purpleline, Line B) on right side off back wall is: 222°57' +/-5'
 

Difference between left and right side boundary on back wall: 7°42' +/-10'
 

2 By using the model

Line B: 3°36' +/- 1'
Line A: 4°45' +/- 2'
Total difference: 8°21' +/- 4'
Line M (combining the figures from section1and this section): 219°40'+/-15'
 

Determination of horizon altitude

The azimuth of the horizon with Ward hill is determined by three photographs: Combining these three pictures gives an overview of the horizon with Ward hill somewhere in the middle.

The purple and green lines are determined by modeling the positionsofthe camera, the entrance location at D and S and the passage at respectivelyG 2 and H2 (see also the overview of the mound).

Using the above picture between the green and the purple line, the altitude of the horizon as a function of the azimuth can be determined. In the below pictures one can see this altitude, which is used as input to themodelof Maeshowe;

(100 pixels are equivalentwith1°)
 

Sunny days

The following days were more or less sunny at Maeshowe. The first threecolumns provide the date information and the following pair of colomnsprovide anapproximation of the amount of sun on the back wall (0%:means sunbehind clouds)for a specific days in the year:
 
 
 

 

# days before/after Date Date 1997 1997/1998 1998 1998/1999 1999 1999/2000 2000 2000/2001 2001 2001/2002
winter solstice before after before after before after before after before after before after
0 Dec. 21 Dec. 21 65% 0% 100% 0%
1 Dec. 20 Dec. 22 0% 0% 0% 0% 0% 0% 0% 0%
2 Dec. 19 Dec. 23 0% 0% 0% 2% 0% 0% 0% ???
3 Dec. 18 Dec. 24 0% 0% 0% 0% 0% 0% 100% 80%
4 Dec. 17 Dec. 25 1% 0% 0% 0% 0% 0% ??? 100%
5 Dec. 16 Dec. 26 0% 30% 0% 0% 0% 0% 0% 0%
6 Dec. 15 Dec. 27 25% 75% 0% 80% 0% 0% 0% 0%
7 Dec. 14 Dec. 28 5% 0% 100% 0% 0% 0% ??? ???
8 Dec. 13 Dec. 29 20% 80% 0% 0% 0% 0% 0% ???
9 Dec. 12 Dec. 30 0% 0% 100% 100% 10% 0% 0% 0%
10 Dec. 11 Dec. 31 0% 50% 0% 0% 0% 0% 0% ???
11 Dec. 10 Jan. 1 0% 0% 0% 0% 50% 0% 0% ???
12 Dec. 9 Jan. 2 0% 100% 0% 0% 0% 0% 0% ???
13 Dec. 8 Jan. 3 ? 0% 0% 60% 0% 0% 0% 100%
14 Dec. 7 Jan. 4 ? 25% 0% 0% 0% 0% 100% 0%
15 Dec. 6 Jan. 5 ? 0% 0% 0% 0% 0% 100% 0%
16 Dec. 5 Jan. 6 ? 0% 0% 0% 0% 45% 0% ???
17 Dec. 4 Jan. 7 ? 0% 0% 10% 0% 0% 0% 0%
18 Dec. 3 Jan. 8 ? 75% 50% 0% 0% 0% 100% 0% 0%
19 Dec. 2 Jan. 9 100%+(?) 0% 0% 0% 0% 65% 0% 30% 50%++
21 Dec. 1 Jan. 10 ? 0% 100%+(2min) 100% 0% 0% 0% 25%++ 0%
21 Nov. 30 Jan. 11 ? 10%++ 0% 100%+(1min) ? 0% 0% 0% 0%
22 Nov. 29 Jan. 12 ? 100% 100% 0% ? 90%+(4 min) ? 100% 0%
23 Nov. 28 Jan. 13 ? 0% ? 0% ? 0% ? 100% ?
24 Nov. 27 Jan. 14 ? 0% ? 0% ? 0% 100% ??? ?
25 Nov. 26 Jan. 15 ? 0% ? 0% 100% 0% ? ??? ?
26 Nov. 25 Jan. 16 ? 75% ? 0% 0% 0% ? ??? ?
27 Nov. 24 Jan. 17 ? 100% ? 0% ? 0% ? 0% ?
28 Nov. 23 Jan. 18 ? 0% ? 0% ? 0% ? 0% ?
29 Nov. 22 Jan. 19 ? 0% ? 100% ? 0% ? 0% ?
30 Nov. 21 Jan. 20 ? 0% ? 0% ? 5% ? 0% ?
31 Nov. 20 Jan. 21 ? 0% ? 0% ? 0% ? ? ?
32 Nov. 19 Jan. 22 ? 0% ? 0% ? 0% ? ? ?
33 Nov. 18 Jan. 23 ? 0% 100% 0% ? 0% ? ? ?
34 Nov. 17 Jan. 24 ? 0% ? 0% ? 0% ? ? ?
35 Nov. 16 Jan. 25 * 0% ? 0% ? 0% ? ? ?
36 Nov. 15 Jan. 26 ? 0% ? 0% ? 0% ? ? ?
+ the sun flashed behind the right side of Ward Hill, the practical proof for my model (between brackets the duration of thereappearance).
++ although partly sun, no sun at a possible moment no reappearing.
* there was sun in the passage but not in the back wall! So between33days before/after winter solstice (like Nov. 18th, 1998)until35 days before/after winter solstice (like Nov. 16th,1997) thesun stops shining on the back wall.
? Not known.
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