| 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 |