MADEFAST Optical Design Information
MADEFAST Optical Design Information
Images created August 19, 1994
The optical assembly shown consists of:
- Parabolic primary mirror
- Status: Design and manufacture complete 10/10/94
- Also serves as inner gimbal
- Nickel and gold plated
- Hyperbolic secondary mirror
- Status: Design and manufacture complete 10/10/94
- Nickel and gold plated
- Spider
- Status: Design and manufacture complete 10/10/94
- Holds secondary mirror
- Anodized to reduce reflection of light
- Shade
- Status: Design and manufacture complete 10/10/94
- Blocks stray light
- Holds PSD in place
- Anodized to reduce reflection of light
- This will be a Stereo Lithography part from CMU
- Rate sensor mountings
- Status: Design and manufacture complete 10/10/94
Design Description
The PSD (Position Sensing Device) position in the following design
descriptions is relative to the center of the surface of the primary
mirror.
Optical Design 4:
Approximate Dimensions and Optical Specifications:
- Primary mirror: 4.06 inch diagonal diameter
- Secondary mirror: 1.56 inch diameter
- Spider: 1.920 inch height
- Focal length: 120mm
- Field of view: 4.76 degrees
- PSD position: +1 mm
The image below shows a ray tracing of the current optical design.
This is a cross section of the primary and secondary mirrors and the
protective dome. The rectangle where the rays converge represents the
PSD.
The benefit of placing the PSD at +1mm is that mounting it becomes
easier, since the optical shade can be used to hold the PSD in
position. This alleviates the need for additional mounting hardware.
By placing the PSD at +1mm, the secondary mirror is enlarged slightly
relative to Optical Design 3, but it should not block a significant
amount of light.
There were several iterations on the placement of the PSD and the
mirrors before the current design was agreed upon.
Carolyn M. Valiquette
cvalique@cs.utah.edu
Images created August 19, 1994