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Cassegrain acquisition and guider Unit

 

At the rear of the INT primary mirror cell is the Cassegrain turntable which can be rotated by 365 degrees, and onto which an A&G unit is mounted. The Cassegrain A&G Unit of the INT has been designed primarily for use with the Cassegrain Intermediate Dispersion Spectrograph (IDS) and Faint Object Spectrograph (FOS-1). Nevertheless, the overall philosophy of the design has been to incorporate a range of facilities which would be required by most instruments operating at the Cassegrain focus. Figure gif shows the layout of the A&G unit. The full field is 20 arcmin in diameter, but the comparison lamps and filters are only useful over a more restricted field of 4 arcmin, matching that of the IDS.

  
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Figure: Three views of the Cassegrain acquisition and guider unit of the INT, showing the autoguider, TV camera, comparison system and filters. (a) and (b) Elevation, (c) Plan

The following functions are provided:



next up previous contents
Next: Prime focus acquisition Up: Acquisition and guiding Previous: Finder telescope




Tue Aug 15 16:42:46 BST 1995