Dish Surface Optimization System |
Caltech Submillimeter Observatory | |
Melanie Leong | |
August 15, 2002 |
Dish Surface Optimization System Agenda |
Primary Specifications | ||
99 Channel Dish Surface Optimization System | ||
Engineering Challenges | ||
Major Milestones | ||
Performance | ||
Test Results | ||
Efficiency with 692 Receiver | ||
Efficiency with SHARCII | ||
Future Plans |
Dish Surface Optimization Sys Primary Specifications |
Desired Performance Specifications | ||
+/- 25 Micron Length Change for Most of Dish | ||
Reduce RMS Surface Error from 25 Micron RMS to 15 Micron RMS | ||
Improve Aperture Efficiency by a Factor of 2, Integration Time by a Factor of 4 | ||
+/- 50 Micron Length Change for Perimeter of Dish | ||
3 Toothpick Controller/Driver Prototype Demonstrated that desired length changes can be achieved | ||
99 Channel Dish Surface Optimization System Requested to Build ASAP |
Dish Surface
Optimization System Diagram |
DSOS Simplified Block Diagram for (1) Channel |
Dish Surface Optimization Sys Toothpick Assembly |
Dish Surface Optimization Sys Dish Wiring & Plumbing |
Dish Surface Optimization System Racks |
Dish Surface Optimization Sys 99 Channel Controller Unit |
Dish Surface Optimization Sys 99 Channel Controller Unit (cont.) |
Dish Surface Optimization Sys 25 Channel Driver Unit |
Dish Surface Optimization Sys 25 Channel Driver Unit (cont.) |
Dish Surface Optimization System Performance |
Command Value to Micron Movement Verifies +/- 25 Micron Desired capability | ||
Power Consumption | ||
Power Draw At Start Up = 4kWatts | ||
Quiescent Power Draw = 840 Watts | ||
Added Weight to Dish - 268 lbs | ||
Approximate Weight of System on 3rd Floor - 1,994 lbs |
Dish Surface Optimization
Sys Length Change Capability |
DSOS Test Results Efficiency with 692 Rx |
Efficiency Done Due to Lack of Planets | |
Determined From Past Holography Maps to Act on (14) Toothpicks out of (99) | |
14% Improvement of Object Temperature w/ 692 Rx | |
All Scans Showed An Improvement | |
Calculated Expected Improvement is 21% with all (99) Toothpicks Activated | |
Indication That The Dish Surface Optimization System is on itŐs way | |
Dish Surface Optimization
Sys 14% Improvement With 692Rx |
DSOS Test Results Efficiency with SHARC II |
Activated (19) Toothpicks. Determined From Past Holography Maps | |
27% Improvement of Peak Signal Power From Uranus | |
All Cycles Showed an Increase in Signal Power When Dish Correction is Applied |
DSOS with SHARCII 27% Improved Signal Power |
Dish Surface Optimization System Future Plans |
Goal is to Obtain a 100% Improvement at 350 Microns | |
High Resolution Holography Maps Need to be Made | |
Interpolation to Determine Command Values in 10 Degree Steps in Zenith Angle for all 99 Channels | |
Calibration of all 99 Toothpick Assemblies | |
Software Control to Speed up Ramp and Settling Time | |
Power On/Off Controller Unit |