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The full observatory (sometimes referred to as PS4) will consist of four 1.8 meter diameter optical systems
that will be aimed at the same point in the sky. Each optical system will have its own independent electronic camera.
What is the optical design of the telescope?
The basis of Pan-SYTARRS is a 1.8-m concave primary mirror that
follow the Ritchey-Chretien design,
Light from the primary is reflected off a convex secondary mirror
to a Cassegrain focus behing the primary. In order to produce good
images over a wide field of view, the light passes through three
corrector lenses before reaching the camera at the focus. Each
of the lenses is about 50 cm in diameter. The focal ratio of f/4
gives a focal length of 8 meters, and plate scale of 38.5 microns per
arcsecond.
How will the mirrors be mounted?
It has not yet been decided how to support the
mirrors. One alternative is to build four separate
mounts, each of which can be controlled independently. The mirrors
would be housed in a single large protective dome.
Alternatively, all four mirrors could be mounted
side-by-side in a single equatorial mount inside a single dome.
Some flexibility would be lost, but the instrument would be
compact enough to be placed inside a comparatively
small dome, such as the one that currently houses the University
of Hawaii's 2.2-meter telescope on Mauna Kea.
Where will Pan-STARRS be located?
We are doing site testing on both observatory locations in Hawaii
-- Haleakala and Mauna Kea. If Pan-STARRS goes to Mauna Kea it will
probably replace the University of Hawaii's 2.2-meter telescope.
The prototype Pan-STARRS telescope, PS1, was built
on Haleakaka
How big is the field of view?
The field of view of the telescope is 3 degrees. This angle is about
the length of Orion's belt, or six times the diameter of the full
moon. It is comparable to that of a typical pair of binoculars,
or a 35 mm camera fitted with a 400 mm
telephoto lens. While this may seem narrow in comparison with a
typical consumer digital camera, it is far wider than commonly
found in astronomical telescopes. The
wide field of view is the main feature of Pan-STARRS that enables
it to survey the sky quickly.
Next: Camera Design
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Ray Trace Diagram
Map of Hawaii
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