The Sky Survey Replaces its Monitor Telescope:
The New Photometric Telescope

Lifting a mounting fork
into the domeThe 0.5-meter telescope from Johns Hopkins arrived at Apache Point in perfect condition, and was installed on schedule (as shown to the right) in mid-August. However the transfer plans were nearly upset by the World Lacrosse Championship held in Baltimore that same week! One of the lacrosse fields used in the tournament is near the JHU astronomy building, so the telescope transport crew wasn't allowed to close the road to the observatory.

The telescope fit inside the dome only after some minor modifications. Because the new telescope is taller than the original, Mark Klaene from APO and John Briggs from Yerkes had to lower the concrete pier. They also added a mounting wedge to correct for the 6.5 degree latitude difference between Baltimore and Apache Point.

The optics and instrumentation of the 0.5-meter telescope had been originally designed for less-demanding student use. In particular, its useful field of view was too small for SDSS purposes. To solve this problem, Shu-i Wang from Yerkes designed a set of field corrector optics, which have enlarged the usable field of view to nearly 1 degree across. Alan Uomoto from JHU has designed a new instrument box, and Takashi Ichikawa, from the Japan Participation Group, built a new shutter. Within two months, the modifications will be complete and can then be tested.

And the price tag on this replacement? Alan Uomoto says, "The total cost is $300,000, three-quarters of it for purchasing a replacement telescope for JHU which, ironically, will have exactly the optics that SDSS would've wanted."

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