Hey George,
A question: with some adaptive optical systems,
you do not, necessarily, need a nearby guide star to
monitor, to use to back out the atmospheric distortion
with mirror actuators. In fact, I would think in this
case, with a satellite (i.e.; the ISS/Shuttle in low
earth orbit) you wouldn't be able utilize stationary
guide stars unless you could work quickly. Instead,
aren't there methods of "creating" a guide star with a
co-axially mounted (sodium?) laser to illuminate the
upper reaches of the atmosphere near the object being
tracked so that you can back out the distortions of
the new guide star/illumination point? And you are
using coherent light. Is there a laser associated with
this system for that purpose?
Regards,
Jeff Umbarger
Plano, TX USA
--- George Roberts <gr@gr5.org> wrote:
> >I'm impressed...
> >http://antwrp.gsfc.nasa.gov/apod/ap070628.html
>
> >I've just put my 8 inch scope in the trash can !!!
> Thanks for the chuckle!
>
> ... or how to make a good satellite photography
> system:
>
> The telescope used to take this picture is a 15
> minute drive
> from my house and I have visited it about 6 times.
> It
> belongs to a private school for K-12 (this isn't the
> only
> impressive part of the school by a long shot - this
> is a very
> rich school). The telescope has a mirror that was
> ground to
> much better smoothness and figure than typical
> mirrors of
> it's size (25 inches). The telescope has an active
> adaptive
> optics system that corrects only in x and y (some
> adaptive
> optics systems have hundreds of correctors).
> According
> to Ron Dantowitz who runs the telescope a single
> corrector
> fixes most of the atmospheric distortion. I don't
> know if this
> system works with photographs like this one where
> there is
> no reference star. But the seeing is very good at
> this location -
> the telescope is mounted on the roof of a 4 story
> building (with
> a pier that runs through all 4 floors into granite
> below -
> vibrationally separate from the rest of the school)
> and
> this building is on top of a hill, and typical winds
> run over
> a large farmer's field before hitting the hill. All
> this reduces
> turbulence. This telescope is used by the Navy each
> night
> remotely (after Ron goes home) to search for planets
>
> around other stars using laser-spectroscopy and Ron
> seems to think it is the most accurate device on our
>
> planet for this purpose because of the telescope's
> unique
> features. Located about 8 miles from light polluted
> Boston -
> obviously one can do serious astronomy in light
> polluted skies.
>
> There is a picture of the building (and the
> telescope dome) in
> the upper corner of this web page:
>
http://www.dexter-southfield.org/podium/default.aspx?t=10557
>
> - George Roberts
> http://gr5.org
>
>
>
>
>
>
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