Direct Access:
If you have an account at NCSA you can access the data directly with "ssh"
ssh **username**@lsst-dev.ncsa.illinois.edu
cd /nfs/lsst/all-sky
Here you will find a directory for each night that data from the all sky camera were collected.
*** I still need to put a pointer for the diode data ***
Web Access:
http://lsst-web.ncsa.illinois.edu/all-sky/
You can use "wget" to retrieve specific files or directories
wget -r -e robots=off http://lsst-web.ncsa.illinois.edu/all-sky/**file or directory name here***
Comparing to the ESO Sky Brightness Calculator:
I use the eso sky calculator to compute the expected surface brightness for each time on the given days. Note these calculations were made for zenith (airmass = 1), and I turned the zodiacal light off for the time being (still need to do some coordinate conversion to calc zodiacal light properly). I'm assuming the Cannon RGB filters map to astronomical R, V, B via a zeropoint shift (e.g., I take -2.5log10 of the skybrightness measurements and add a zeropoint to match the median of the model in the middle of the night).
A nice dark night. The model says the sky brightness should be pretty constant and the data look pretty constant.
Moon starts up and sets during the night. The model predicts the sky should be brighter at the start of the night.
Moon rises during the night. Model seems to get the first part of the rise pretty well, but then the sky gets much brighter than the model.
Nearly full moon rising at the start of the night (as full moons tend to do). Those are clouds hitting at the end of the night, but I'm not sure why the measured brightness goes to such a monster peak in the middle of the night.
Preliminary thoughts:
- Running the ESO calculator over the web is really slow and painful
- The ESO model doesn't include twilight at all!
- Looks like there is an issue with the sky brightness measurements once the moon gets above a certain elevation.