Re: Can I have this RC when the mission is done???

From: William C. Keel (keel_at_bildad.astr.ua.edu)
Date: 12/17/04 

Date: 17 Dec 2004 12:15:37 -0600

Thomas Womack <twomack@chiark.greenend.org.uk> wrote:
> In article <41c2e5cc$1@news.ua.edu>,
> William C. Keel <keel@bildad.astr.ua.edu> wrote:
>>RichA <none@none.com> wrote:

>>> On a more serious note, no one does ground-based ultraviolet study, do
>>> they?

>>Not as long as we've left some of the ozone layer in place, no.

> Would going to Antarctica help, or is the ozone hole only a relative
> depletion of ozone, so there's enough left to absorb in the UV?

Only slightly - across most of the UV, absorption is something like
a factor-of-100,000 thing, so half that doesn't help much. You
can nibble around the edges of the problem a bit, though. Antarctic
winter might let you work a little farther into the UV than
other sites (280nm instead of 300?). Being in a high dry site
helps right around the cutoff, where scattering by small particles
ca also be important. Don Hayes (guru of photometric calibrations)
put together a table years ago showing that from typical mountaintops,
this scattering was as important as ozone absorption around 320nm.
I recall seeing some spectra from Mauna Kea that were usable down
around 310. (For bright enough targets, you can go a bit farther - I
dimly recall a spectrum of Venus taken from altitude 1300 m which
went down almost to 280 nm).

Bill Keel

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