Appendix 9 - CCD Orientation

  1. f/3.3 Prime Focus
  2. f/8 Auxiliary Focus

9.1 f/3.3 Prime Focus

With the possibility of mounting the CCD in any orientation (though its usually limited to any of the four orientations which align the rows and columns with RA and DEC), and the camera head itself being in any of four orientations, it is difficult to offer any firm guidlines on what your field orientation will be.

However, usually the TEK CCD is mounted as it is shown in Figure 3.1  with the  CCD electronics box directed down when the telescope is at prime focus access (or N when the telescope is at the zenith). Whenever the electronics box is pointing in that direction, then the orientation you will have is

Now of course, if you had the CCD originally oriented in the `box down' direction, but rotated the camera head, then you'll have a different orientation.

9.2 f/8 Auxiliary Focus

Here again, you have the uncertainty of which way the CCD is mounted, and which way the Cassegrain A&G box is rotated. However, usually you'll have the Blue thomson mounted with its electronics box pointed downwards as you look at the dewar in the Cassegrain cage. And often you'll be observing with the Cassegrain rotator at 90 degrees. In this case you'll see

Introduction The Telescope & optics The Detectors
The Imaging Cameras An Imaging Cookbook The Data you Take Away
Exposure times OFFSET_RUN files CCD Windows Data Catalogs
On-line Reduction Filters Flat-fields Blank Fields Orientation Shutters

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This Page last updated:  27 Nov 1997, by Chris Tinney