Why are you going with four small mirrors instead
of one larger telescope?
It is much quicker and cheaper to design
and build several small optical systems than one large one with
the same collecting area. There is also much less technological
risk. The downside to using four mirrors is that we need four
cameras and a lot more computing power. But the cost of electronic
chips and of computers is dropping so rapidly that the multi-system approach is far more economical.
Will the four mirrors always be pointing in the same direction?
Usually, yes. With four images of the same region of sky we
can not only collect more light, but can eliminate flaws that occur
in a single image due to cosmic rays, bad pixels, and gaps between
adjacent CCD chips. However, we also have the option of using different
filters in each telescope and measuring four colors simultaneously
for certain kinds of studies. Depending on how the mirrors
are mounted we may also be able to point them in four different
directions, if we need to make a particularly rapid survey.
Will the four mirrors be used as an interferometer?
There are no plans to connect the four optical systems as an interferometer.
Will the four optical systems be built at the same time?
The first telescope, called PS1, has been built as a self-contained
prototype instrument. It is used to test hardware and software
for the completed instrument, and to set up a grid of astrometric
and photometric standards. It is also undertaking an extensive program of scientific observations for the Pan-STARRS Scientific Consortium
Can Pan-STARRS be built with today's technology?
Yes. All of the basic technology is already known. The telescope
designs are fairly standard. The CCD focal plane cameras will employ
Orthogonal Transfer CCDs (OTCCDs) that have been developed at Lincoln
Laboratory and tested at the UH 2.2-meter telescope on Mauna Kea. The
computer-processing pipeline is scalable from systems used to analyze
data from the current generation of imaging CCD mosaics such as
the 12K and MegaCam CCD arrays on the Canada-France-Hawaii telescope.
Pan-STARRS will integrate these various components into a finely
tuned data gathering, processing, and analysis system.
Next: Telescope Design
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