You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
18 September 1997Chopping secondary mirror control systems for the W. M. Keck Telescopes
The Keck 1 chopping secondary was built by the Palo Alto Research Laboratories of the Lockheed (now Lockheed Martin) Missiles and Space Company. The only software component of the delivered system is a proprietary error correction algorithm; Keck wrote software to generate acceleration-limited azimuth and elevation demands, to rotate these demands as a function of telescope position, to interact with the error correction system, and to mange hardware start-up and shutdown. The Keck 2 chopping secondary, also built by Lockheed, was originally conceived as an infrared fast steering mechanism (IFSM) and is simpler than the Keck 1 system, with lower power and acceleration limits and, therefore, lower chop amplitude and frequency specifications. As far as possible, it provides the same external interfaces as the Keck 1 system. A new EPICS- based telescope control system has been written for Keck 2 and was retrofitted on Keck 1 in March 1997. The Keck 1 chopper control software has been converted to the EPICS environment and, at the same time, altered so that the same software supports both choppers. This conversion has retained as much as possible of the complex real-time code of the old system while at the same time fully utilizing EPICS facilities. The paper presents more details of both the old and the new systems and illustrates how the new system is simpler than the old as well as being much better integrated into the overall telescope control system. Operational experience is presented.
William Lupton
"Chopping secondary mirror control systems for the W. M. Keck Telescopes", Proc. SPIE 3112, Telescope Control Systems II, (18 September 1997); https://doi.org/10.1117/12.284227
The alert did not successfully save. Please try again later.
William Lupton, "Chopping secondary mirror control systems for the W. M. Keck Telescopes," Proc. SPIE 3112, Telescope Control Systems II, (18 September 1997); https://doi.org/10.1117/12.284227