White Helmets cave complex
The back wall of this entrance forms a sundial.
The concrete molding slats on the west wall form the time markers. The black arrow is on slat 14 from top.
The shape of south wall is approximately square.
The south wall is 29 slats high and about 30 slats wide.
Earliest photo, around 7:10 am
Shadow on text, 7 slats from top.
Shadow just above arrow, 11 slats from top: 20 degrees at 8:00 am
Shadow below arrow, 14 slats from top. 25 degrees at 8:25 am
Shadow 16 slats from top. Must also take into account the changing azimuth.
Children on truck are seen on same EMC video around 7:25
Note the shadow in the background under the concrete slab roof.
EXIF data provided by Reuter says Date and time of data generation: 10:00 am, 4 April 2017.
Also 10:00 am. A similar estimate can be made from shadows, so this timestamp could be from camera with the time set to Syrian daylight saving time.
Same event, staged by another White Helmet. The shadow hints that this is a few minutes earlier
Explosions hit the cave complex.
8:12 - First mention of chemical attack in Whatsup group used by doctors in the area.
8:30 - ("closer to") Dr. Islam claims to start receiving patients at his clinic 60 km and 45 minutes drive away from Khan Sheikhoun.
9:29 - First casualties reported at Jarjanaz clinic.