Sky light, sky bright,
Only sky I'll see tonight,
I wish I may, I wish I might,
Know the sky I'll see tonight.
skybright is a tool for esitamting the sky brightness (in
magnitudes/asec^2) of a given set of celestial coordinates, from a
given site, at a given time, in a given filter.
It use a simple model with four components:
- An airglow shell in the Earth's atmosphere
- Rayleigh scattering of moonlight
- Mie scattering of moonlight
- A very simple algebraic estimation of twilight.
From a shell, it can be executed thus:
$ skybright --help
usage: Estimate the sky brightness [-h] [-m MJD] [-r RA] [-d DEC] [-f FILTER]
[-c CONFIG]
optional arguments:
-h, --help show this help message and exit
-m MJD, --mjd MJD Modified Julian Date (float) (UTC)
-r RA, --ra RA the RA (decimal degrees)
-d DEC, --dec DEC the declination (decimal degrees)
-f FILTER, --filter FILTER
the filter
-c CONFIG, --config CONFIG
the configuration file
$ skybright -m 58008.4 -r 40.0 -d -5.0 -f i -c etc/skybright.conf
Moon zenith distance: 47.645061
Sun zenith distance: 105.734680
Elongation of the moon: 101.444917
Moon brightness: 0.132464
Pointing angle with moon: 35.179739
Pointing zenith distance: 34.326929
Airmass: 1.210294
Sky brightness at pointing: 19.249708
The jupyter notebook in
doc/skybright.ipynb shows the use of
the python API.