This vertical sundial was installed in memory of the 100th anniversary of the Camp (1915-2015)
How to read a sundial set to true solar time?
- Traditionally, a sundial indicates true time and not the official time.
- In summer, one hour must be added to the time indicated on the dial.
- Every day of the year, 33 minutes are added. This is due to the fact that we are in a place in the time zone where we are 33 minutes out of true solar time; this is the longitude deviation.
- The equation of time must also be taken into account, as the length of a day is not constant throughout the year. To do this, consult the table below, which shows us the minutes and seconds (average values) to be subtracted or added for the given day.
Table of average values
| Days | Jan. | Febr. | March | April | May | June | July | Aug. | Sept. | Oct. | Nov. | Dec. |
| 1 | (+) 3’16" | (+) 13'33" | (+) 12'34" | (+) 4’09" | (-) 2’51" | (-) 2'25" | (+) 3'34" | (+) 6'18" | (+) 0'15" | (-) 10'03" | (-) 16'21" | (-) 11'15" |
| 5 | (+) 5'07" | (-1) 14'00" | (+) 11'44" | (+) 2'57" | (-) 3’18" | (-) 1'47" | (+) 4’19" | (+) 6'00" | (-) 1’03" | (-) 11’19" | (-) 16'24" | (-) 9’42" |
| 10 | (+) 7’16" | (+) 14'17" | (+) 10'32" | (+) 1’32" | (-) 3’39" | (-) 0'52" | (+) 5’08" | (+) 5'25" | (-) 2’45" | (-) 12'45" | (-) 16'08" | (-) 7'33" |
| 15 | (+) 9’12" | (+) 14'14" | (+) 9'12" | (+) 0’13" | (-) 3'45" | (+) 0'10" | (+) 5'46" | (+) 4'35" | (-) 4'30" | (-) 14'00" | (-) 15'30" | (-) 5’13" |
| 20 | (+) 10’51" | (+) 13'53" | (+) 7'46" | (-) 0'56" | (-) 3'37" | (+) 1’15" | (+) 6’13" | (+) 3'33" | (-) 6’16" | (-) 15'01" | (-) 14'32" | (-) 2'47" |
| 25 | (+) 12'13" | (+) 13'15" | (+) 6'16" | (-) 1'55" | (-) 3’15" | (+) 2'20" | (+) 6'26" | (+) 2’18" | (-) 8’01" | (-) 15'47" | (-) 13'14" | (-) 0'18" |
What Time is it?
| Winter | Location | Summer |
| Winter time / Summer time | + 1 Hour | |
| + 33 Minutes | Longitude difference in Vaumarcus | + 33 Minutes |
| + Equation of time | Variation of the length of the time, to be readed in the table below | + Equation of time |
Example : First of August, 12h on the dial = 12h + 1h + 33 minutes + 6 minutes = 13:39
| Days |
Jan. |
Febr. |
March |
April |
May |
June |
July |
Aug. |
Sept. |
Oct. |
Nov. |
Dec. |
| 1 | + 3' | + 13' | + 13' | + 4’ | - 3' | - 2' | + 4' | + 6' | 0' | - 10’ | - 16' | - 11' |
| 5 | + 5’- | + 14' | + 12' | + 3’ | - 3’ | - 2’ | + 4’ | + 6’ | - 1' | - 11' | - 16' | - 10’ |
| 10 | + 7’ | + 14' | + 11' | + 2’ | - 4’ | - 1' | + 5’ | + 5’ | - 3' | - 13' | - 16' | - 7’ |
| 15 | + 9' | + 14' | + 9' | 0' | - 4' | 0' | + 6' | + 5' | - 5' | - 14' | - 15' | - 5' |
| 20 | + 11' | + 14' | + 8' | - 1' | - 4' | + 1' | + 6' | + 4' | - 6' | - 15' | - 14' | - 3' |
| 25 | + 12' | + 13' | + 6' | - 2' | - 3' | + 2' | + 6' | + 2' | - 8' | - 16' | - 13' | 0' |
