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Check the following:
- The comparison lamps should be on, and the
comparison lamp shutters open. It is possible to check
that the comparison lamps are drawing current by inspecting
the meters in the NAG electronics rack on the Nasymth platform.
- Check the mimic to see which diffuser is in the beam.
At a wavelength of 5000 Å, the wideband diffuser decreases
the intensity by a factor of about 350 compared to having no
diffuser in the beam.
At a wavelength of 3500 Å, the UV diffuser decreases
the intensity by a factor of about 40 compared to having no
diffuser in the beam.
The diffuser is only normally essential for longslit work.
Changing the diffuser can only be done manually; ask your
Support Astronomer.
- Check the mimic to see that the autoguider mirror is in the
ULAMPS position.
- Check the mimic to see whether the slit shutter
opens and closes during an exposure.
- The echelle gratings have dust covers, which should have
been raised at the start of the observing run. The only way
to check this is by opening up the thermal enclosure, so only try
this after trying everything else first. Only
the support astronomer or duty tech should open up the enclosure.
- Check on the mimic display that the camera shutter is out.
- Check on the mimic display that the interface cover is off.
The interface cover cannot be moved under computer control;
ask your support astronomer or duty tech if it needs to be
moved.