The all-sky DayCams take images of
the entire sky at regular intervals.
When the sun is visible in clear skies it shows as a dark spot (the CMOS detector saturates) surrounded by an aureole caused by forward scattering in the Earth's atmosphere as well as scattering due to small surface imperfections in the reflecting ball.
Frequently there will be a bright spot opposite the sun. Early
in the morning dew sometimes forms on the surface of the reflecting ball. It
disappears by mid-morning. We may add a heater inside the ball to reduce dewing.
The camera used for our DayCams is not sensitive enough to display stars at
night. It is sensitive enough to show the moon if the exposure time is set to
its maximum but the sun then badly saturates daytime images. We are working
on software to change the exposure time automatically at sunset and sunrise.
