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trinitree88
2010-Feb-22, 07:57 PM
The night sky glows in a greenish hue due to ozone reforming oxygen, once the sun's ultraviolet is taken out of the equilibrium. For dark sky sites, this can hinder subtle measurements if you are looking through the glow, and, in a range near maximum (lambdamax) effect. Consequently,these authors monitor the brightness variability throughout the night at Cerro Tololo, with considered application for other similar sites like Cerro Paranal. SEE:http://arxiv.org/PS_cache/arxiv/pdf/1002/1002.3637v1.pdf

The picky, but important, way for new instrumentation to be calibrated. It's a good thing the world makes lots of different kinds of people.:shifty: pete

George
2010-Feb-23, 07:34 PM
The night sky glows in a greenish hue due to ozone reforming oxygen, once the sun's ultraviolet is taken out of the equilibrium. I would bet it's blue, using enhanced eyeballs. [The universe, as a whole, was first deemed green, but then the rage was beige. ] :)

It looks like the paper is suited for y-band imaging, which is about 1 micron stuff.


The picky, but important, way for new instrumentation to be calibrated. It's a good thing the world makes lots of different kinds of people.:shifty: pete I like the colorful ones best.

matt.o
2010-Feb-23, 09:15 PM
I haven't looked at the paper, but 1 micron is about where the skylines dominate in the optical and sky subtraction becomes an issue. See this sky spectrum as an example. (http://www.gemini.edu/sciops/ObsProcess/obsConstraints/atm-models/opt-emiss.gif) Note that green has a wavelength of ~550 nanometers.

ngc3314
2010-Feb-23, 10:02 PM
There are some interesting movies of sky glow, either in the optical lines (http://www.youtube.com/watch?v=Qdu9ayRnEAE&feature=player_embedded) (Na 5893 A, [O I] 5577 and 6300 A) or the near-IR (http://www.astro.virginia.edu/~mfs4n/2mass/airglow/adams/h1.mpg) where OH is the culprit. Bands march across the sky (V) on few-minute timescales, and the near-IR OH emission lines accompanying them are a source of error in some IR imaging applications (as the spectrum of the blank sky changes, so may the flat-field calibration pattern).

HENARRY JAYA
2010-Mar-04, 05:20 AM
In a sense you are both right. The whole of Southern England is contaminated by sky-glow. The sky-glow from London affect an area with a radius of up to 100km. So unless you were more than 100km from London, part of the sky glow you saw was from London.
A lot of the rest of it was from other industrial sources in and around London. It seems like it's getting impossible these days to get away from it.