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Focusing and Orientation of the Acquisition Bundle

The end of the acquisition bundle in front of the TV camera should be focussed, using the manual mechanism (see Figure 3). In principle there are two procedures, both requiring the interaction of two people: one at the GHRIL (moving the focus mechanism), and the other in the control room watching the TV screen.

i) With the bundle connected to the to the SP, the inside of AG&C box is illuminated (e.g., with a torch, a faint dome light, etc). By inspecting the edges of the image bundle on the TV screen, the best focus can be determined. If the focus remains unsatisfactory the following procedure must be used (as a last resort).

ii) The bundle is dismounted from the SP (see INT-IAC-PRC001), and connected to a dedicated focusing system. This system allows a test image (e.g., a number) to be seen through the bundle.

Currently, a painted mark is used to fix the bundle orientation. However, we anticipate that before the instrument reaches common user status the bundles will be doweled in the correct positions.

In order to aid night-time acquisition the outline of the bundle should be marked on the TV screen.

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Wed Feb 11 16:14:30 GMT 1998