Echellette Spectrograph and Imager
(Most images can be clicked on to view a larger version)
These are photos of the moving prism mount and translation stage. It has
been fabricated and is being tested with a dummy prism installed. The
dummy prism is an aluminum mockup, filled with concrete to simulate the
mass of the prism. The following tests will be performed.
- Repeatability of the translating mechanism
- Force needed to backdrive the ball screw
- Holding power of the brake
- Optical tilt of the prism under:
- Varying gravity
- Translation of the stage
- Hysteresis of the translation mechanism
These are photos of the QC tests performed on the actual x dispersing
prisms for ESI. Mechanical dimensions and angles were confirmed. Both
prisms were also tested interferometrically in double pass. Specs for
the test:
- Aperture: 6 inches
- Subapertures tested: 2, top and bottom of the prisms
- Test wavelength: .6328 microns
- Path: double pass
- Temperature: 20 C
Here are the resulting interferograms
The prism is now having mounting pucks glued onto the glass.
There is a paper written by Andy Sheinis titled
"Large Prism Mounting to Minimize Rotation in
Cassegrain Instruments" that deals with this subject
