Next: The Grating
Particularly delicate and vulnerable pieces of instrumentation on the
spectrograph are the CCD camera, acquisition TV, and gratings. The observer must
take special care to observe the following:
- NEVER tinker with the CCD dewar, CCD electronics box, or
cabling. See Chapter 11 for explicit precautions.
- NEVER blast the CCD or acquisition TV with excess light levels, as
e.g. from comparison lamps, dome lights, bright stars, etc.
An excessively bright image on the CCD may require days to decay. Overillumination
of the acquisition TV may be fatal to the intensified Vidicon. See CCD
Manual for information on illumination limits of the CCD and Chapter 5 of this
manual for further information regarding the acquisition TV camera.
- THUNDERSTORMS: When thunder can be heard from the Bok walk,
or the antenna on the Bok walk is ticking, turn off the CCD
interface power supply, CCD controller, the Sun computer and all of
its peripherals. Do not depend on the mountain crew to do this --
they cannot be on site at all times.
- NEVER touch or attempt to clean a grating in any way. Even air
jets can be harmful, as shop-quality compressed air contains an oil
mist and cans of ``Dust-Off'' occasionally squirt a stream of liquid
propellant. Always close grating covers before removing them from the
spectrograph and reopen covers only after locking them into the
- Treat the instrumentation with respect and care. These are expensive
pieces of facility hardware which are essential to the research programs of
many scientists. No crank, knob, or lever should require excessive force
for operation. If it does, something is wrong, and further damage will almost
certainly result from additional elbow grease. Tell your telescope operator
of the problem. If he/she cannot solve it, consult the appropriate calling list for
Next: The Grating
Pat Hall - Wed Oct 4 11:02:37 MST 1995