User's Guide to the Kast Double Spectrograph

Table of Contents

Quick Reference
Hardware Overview
Common Path
Blue Side
Red Side
Detector Characteristics
Kast Controller
Data Taking System
Position Angle
Arc and Flat-field Lamps
Diagonal Mirror
Kast Focus
Telescope Offset
Setup and Observing Hints
Setup Procedures
Observing Hints
Calibration Lamp Spectra
Exposure Time Calculator

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Diagonal Mirror

There is a diagonal mirror in the TUB used to direct light into the science instrument, guide camera, both or neither. The four positions for the diagonal mirror can be selected from the sdiagmir_fe program. sdiagmir_fe is started by clicking on its icon on either the gouda or karnak computers.
  • Position 1 puts the diagonal mirror out of the light path, sending all light into the science instrument.

  • Position 2 puts a full surface flat mirror into the beam, which diverts all the light to the guide camera for field acquisition; no light reaches the detector. A white card on the back of the mirror in position 2 directs light from the TUB quartz or line lamps onto the slit for setting up or wavelength calibration.

  • In position 3, a portion of the diagonal mirror that has a hole in it is positioned so that light from the object passes through the hole to the detector, and the surrounding mirror is available for offset guiding.

  • In position 4, the mirror is entirely out of the way, but a periscope is in position to view the slit. The slit jaws are tilted slightly, and light reflected from them is directed to the periscope, which passes the light on to the guide camera for guiding.

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Last modified: Mon Mar 30 15:23:00 PDT 2009