Glenn's Pennsic pages copyright 1997 by Fred Blonder and D. Glenn Arthur Jr. Last updated 1997.

# Build A Pennsic Sundial

## Fred Blonder's Sundial for Clan Cambion

For Pennsic XXVI, Fred Blonder built a vertical sundial. While the design was complicated by his decision to make it correct only for mid-August at Pennsic, thus incorporating seasonal corrections and daylight-savings-time into the calculations, use of the sundial was greatly simplified by this. Incorporating those calculations into the design rendered the resulting instrument less general (it's only accurate in August), a user who wishes to read the time need not deal with the seasonal corrections needed for a year-round sundial and the lattitude/longitude corrections of a portable one. Below are the angles he computed, so that others can build similar sundials if so inclined. I, for one, would love to see sundials sprinkled around the site. Perhaps a couple of large-ish ones for the merchant areas?

As he was camping with Clan Cambion, Fred painted his sundial to resemble the clan's device -- sable, with a checkered border and a bar sinister, argent. The colour made it a bit difficult to read from a distance, unfortunately, but it did keep accurate time. It was positioned at the gate of the Clan Cambion campsite. Being a South-facing sundial, it had to be on the inside of the gate. (Clan Cambion was camped on the South side of Howard's Fenway.)

## Table Of Angles -- build your own!

The text from here down is by Fred Blonder:

Angles are measured increasing counterclockwise, with zero being straight down. Facing the dial from the south you see:

```  <-- West  East -->
-90 ======================================================================++------ +90
/||\
/ || \
/  ||  \
/   ||   \
/    ||    \
/     ||     \
-45           +45
00
```

The vertical "zero" line is duplicated and separated by the thickness of the gnomon.

The gnomon:

```    This	|\ <- 49.03 Degrees
side	| \
attaches ->	|  \
to		|   \
dial	|    \
face.	|     \ <- 40.97 Degrees
======================================================================
```

The number of decimal places is absurd. I can't measure that accurately. ;-)

```   Time    Shadow angle
A.M.:

7:30 - -88.376789
7:35 - -86.722532
7:40 - -85.070620
7:45 - -83.422216
7:50 - -81.778465
7:55 - -80.140482

8:00 - -78.509349
8:05 - -76.886106
8:10 - -75.271748
8:15 - -73.667219
8:20 - -72.073410
8:25 - -70.491153
8:30 - -68.921219
8:35 - -67.364317
8:40 - -65.821093
8:45 - -64.292127
8:50 - -62.777933
8:55 - -61.278962

9:00 - -59.795601
9:05 - -58.328176
9:10 - -56.876950
9:15 - -55.442128
9:20 - -54.023862
9:25 - -52.622247
9:30 - -51.237328
9:35 - -49.869105
9:40 - -48.517530
9:45 - -47.182515
9:50 - -45.863933
9:55 - -44.561622

10:00 - -43.275386
10:05 - -42.005000
10:10 - -40.750212
10:15 - -39.510747
10:20 - -38.286304
10:25 - -37.076568
10:30 - -35.881202
10:35 - -34.699856
10:40 - -33.532169
10:45 - -32.377764
10:50 - -31.236258
10:55 - -30.107258

11:00 - -28.990366
11:05 - -27.885176
11:10 - -26.791280
11:15 - -25.708265
11:20 - -24.635716
11:25 - -23.573217
11:30 - -22.520352
11:35 - -21.476701
11:40 - -20.441847
11:45 - -19.415375
11:50 - -18.396867
11:55 - -17.385910

P.M.:

12:00 - -16.382090
0:05 - -15.384997
0:10 - -14.394221
0:15 - -13.409355
0:20 - -12.429994
0:25 - -11.455734
0:30 - -10.486176
0:35 -  -9.520919
0:40 -  -8.559566
0:45 -  -7.601723
0:50 -  -6.646996
0:55 -  -5.694992

1:00 -  -4.745321
1:05 -  -3.797594
1:10 -  -2.851421
1:15 -  -1.906416
1:20 -  -0.962191
1:25 -  -0.018360
1:30 -   0.925463
1:35 -   1.869665
1:40 -   2.814633
1:45 -   3.760753
1:50 -   4.708413
1:55 -   5.658001

2:00 -   6.609906
2:05 -   7.564521
2:10 -   8.522235
2:15 -   9.483443
2:20 -  10.448541
2:25 -  11.417925
2:30 -  12.391994
2:35 -  13.371149
2:40 -  14.355793
2:45 -  15.346332
2:50 -  16.343172
2:55 -  17.346722

3:00 -  18.357394
3:05 -  19.375600
3:10 -  20.401755
3:15 -  21.436274
3:20 -  22.479575
3:25 -  23.532074
3:30 -  24.594190
3:35 -  25.666340
3:40 -  26.748940
3:45 -  27.842405
3:50 -  28.947148
3:55 -  30.063578

4:00 -  31.192099
4:05 -  32.333111
4:10 -  33.487007
4:15 -  34.654170
4:20 -  35.834977
4:25 -  37.029791
4:30 -  38.238962
4:35 -  39.462826
4:40 -  40.701702
4:45 -  41.955888
4:50 -  43.225662
4:55 -  44.511277

5:00 -  45.812959
5:05 -  47.130904
5:10 -  48.465277
5:15 -  49.816206
5:20 -  51.183781
5:25 -  52.568049
5:30 -  53.969015
5:35 -  55.386635
5:40 -  56.820815
5:45 -  58.271406
5:50 -  59.738206
5:55 -  61.220952

6:00 -  62.719322
6:05 -  64.232932
6:10 -  65.761333
6:15 -  67.304013
6:20 -  68.860394
6:25 -  70.429833
6:30 -  72.011625
6:35 -  73.605000
6:40 -  75.209128
6:45 -  76.823121
6:50 -  78.446037
6:55 -  80.076882

7:00 -  81.714618
7:05 -  83.358166
7:10 -  85.006410
7:15 -  86.658207
7:20 -  88.312394
7:25 -  89.967791
```
 (* email D. Glenn Arthur Jr. * Glenn's Pennsic page * Fred's pre-calibrated vertical sundial * Fred's pre-calibrated ring sundial * Glenn's camping without a cooler page * Pennsic photo preview page * Map Of My Web Pages * my main page * about me * musings and observations * me the musician * writings * events * humour *)