UNIVERSITY OF WISCONSIN River Falls

Time Lapse Sequence

Sundial SummerNote the arrow which points to the end (except for this one) of the shadow of the Gnomons in each of the pictures. This sequence of 8 pictures, approximately 1 hour apart, was taken from a video filmed on 6/19/95 just two days before the solstice. Even though only one frame per second was recorded, the full video is far too large to down-load over the net at a resolution good enough to see the shadow.

The arrow on this picture points to the Gnomon's shadow but not to the end of it which is obscured by the tree and is in fact on the pillar. Although the Sun had been shining for several hours when this picture was taken, it had risen North of East and therefore the wall was in shadow for some time. When the Sun was eventually to the South of East, the end of the shadow of the Gnomons was too long and fell on the ground. This picture was taken just before the end of the shadow registered on the wall.

Sundial Summer 2The shadow of the pillar to the right (East) diminishes as the Sun moves West. 

Sundial Summer 3The time indicated is 11:30am Central Daylight saving Time or 10:30am Central Standard Time.

 Sundial Summer 4

 Sundial Summer 5

Sundial Summer 6 

Sundial Summer 7The shadow of the pillar on the Left (West) is now increasing in size

Sundial Summer 8This is the last in the sequence because in the next hour the end of the shadow of the Gnomons is on the ground.

Sundial Summer 9