Echellette Spectrograph and Imager

Tasks, Tests and Results

Tasks To Do

• DONE...Align collimator to bearing.
• DONE...Focus collimator.
• Measure location of slit mask.
• Align collimator actuators to optical axis. (Requires darkness)
• Align grating.
• Align prisms.
• Align camera.(Requires darkness)
  1. Translation of axis with laser.
  2. Tilt with spectra.
• Align imaging mirror.

Test Requested

• List of "ESI Precommisioning Tasks" requested by Keck (Bob Goodrich)
• Optical
  1. Perform interferrometric analysis of the two mirror stages, and the prism stage, to determine deflections of fully loaded stages at various spacial orientation.
  2. Measure actual field location of the optical center of the filter wheel.
  3. Measure collimator actuator alignment to telescope axis.
  4. Check focus of collimator
  5. Measure instrument flexure over full range of travel. (Requires darkness)
• Mechanical
  1. Determine positioning repeatability of post dispersion prism. (Requires darkness)
  2. Determine positioning repeatability of imaging mirror. (Requires darkness)
  3. Remove and re-install grating to determine positioning repeatability. (Requires darkness)
• Electrical
• Software
• Other

Results

• Optical
• Mechanical
  1. Ran slit mask wheel under servo control. Rotation target of 2 RPM achieved. Steel belt tracked well with slight vertical displacement upon direction reversal. All three (slit mask, filter, aperture) wheels were operated under servo control at 0 degrees C. Sample torques at this temperature were; .15-.68, .21-.72, .09-.69 Amps. Warm torques of; .11-.60, .12-.69, .24-.52 Amps show that no unexpected binding occured while operating a near zero temps.
  2. Width of Renishaw magnetic fiducial found to be ~76 microns using the slit mask wheel to measure it. Backlash (including windup) of the wheel was measured to be about 15 microns in it's current configuration.
• Electrical
• Software
  1. Collimator actuators ran from limit to limit while supporting a simulated collimator. Ganged motion of all three actuators operating under dual-loop mode performed well.
  2. GUI and control software operational and controlling 10 of 12 stages. CCD exposures now under GUI control.
• Other
  1. Temperature sensors