It seemed like a cloud either began to pass in front of the sun (edge of cloud)
on scan 20 or did so very soon after.

The third set of scans (21-30) were marginal since there were many clouds
and the sun was near the horizon. Had to wait a few times for clouds to pass
between scans. Smoke from the smoke stack of the Merian could be a contaminant
for the whole set as the first few were taken with the base of the stack near
the path to the sun (but the path was below the top of the smoke stack) and
above the smoke stack but to the side (but smoke could still mix over
depending on the wind) for the rest, which were taken from the deck above
the bridge. Also, clouds were close to many of the scans. See photos for
locations the scans were done, proximity to smoke stack, and cloud situation.
More than one photo was taken at each location with different exposure
settings (obtained by telling the cell phone to focus on different parts
of the sky near the sun with differing brightnesses).

A note for future researchers using the instrument from aboard ships. It is
much easier to aim the instrument at the sun while sitting down on the ship,
even the deck of the ship, than while standing.


-- Freja Nordsiek (freja.nordsiek@ds.mpg.de)