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On the left you can see the detector used on the telescope in the late
70's and early 80's called a photometer. It was used to measure the brightnesses
of stars one at a time. To the right is a detector called a CCD (Charge
Coupled Device) which was used during the late 80's and throughout the 90's.
It is basically an electronic camera that measures and outputs numerically
the brightnesses of (390 x 584) locations all across the field the telescope
is observing. It allows one to observe several stars at once and it detects
photons (particles of light) with much greater efficiency than our eyes
do. |
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To the left one can see a liquid nitrogen dewar connected to the CCD. It is necessary to
cool the detector to observe faint objects. To the right one can see the metal box which
contains a readout of the CCD temperature. We start observing when the temperature reaches
-100 degrees Celsius. |
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To the left one can see our filter bolts. These contain squares of colored glass which only allow
certain colors of light through to the CCD. The bolt can slide back and forth underneath the
telescope. Thus, we can measure the brightnesses of stars in different colors.
To the right is a picture of our data room. Our telescope operation is highly automated
requiring very little human interaction. The pointing of the telescope, the sliding of the filter bolts,
and the taking of CCD frames is all done by computer. |
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