BIG motion: Ultra-precise positioning for the largest telescope in the northern hemisphere

After seven years of construction, the largest optical telescope in the northern hemisphere, the Gran Telescopio Canarias (Grantecan) on La Palma, Spain, has begun trial operation. Heidenhain model ERA 780C angle encoders are being used to position the telescope. The telescope rotates about two axes: elevation (vertical motion) and azimuth (horizontal motion); earth motion also requires compensation during the sometimes hour-long observations.

04/24/2008


Schaumburg, IL — After seven years of construction, the largest optical telescope in the northern hemisphere, the Gran Telescopio Canarias (Grantecan) on La Palma, Spain, has begun trial operation. Heidenhain model ERA 780C angle encoders are being used to position the telescope — a solution that has already proven itself in numerous telescope projects. The telescope rotates about two axes: elevation (vertical motion) and azimuth (horizontal motion). In addition, the motion of the earth has to be compensated during the sometimes hour-long observations.
The angle of the azimuth axis is measured over a diameter of about 15 meters, which requires a scale tape with a length of 48.48 meters. 1,212,000 lines with the scale-tape grating period of 40Calibration and compensation of systematic errors bring a system accuracy of 0.06 arc secs (1.7E-5º) over 13.2°. Each scale is installed in a slot about the respective axis of motion and is provided with a suitable number of measuring heads.
The 105 million euro system is now in a test phase lasting one year. The hyperbolic telescope mirror consisting of 36 hexagonal segments will be expanded segment by segment until it reaches the total diameter of 10.4 meters. At the same time, all instruments will be adjusted. When ready for operation, the telescope will focus four million times more accurately than the human eye. It will enable astronomers to detect more details than ever before.
Edited by C.G. Masi , senior editor
Control Engineering Machine Control eNewsletter
Register here and scroll down to select your choice of eNewsletters free .





No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
2015 Top Plant: Phoenix Contact, Middletown, Pa.; 2015 Best Practices: Automation, Electrical Safety, Electrical Systems, Pneumatics, Material Handling, Mechanical Systems
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Special report: U.S. natural gas; LNG transport technologies evolve to meet market demand; Understanding new methane regulations; Predictive maintenance for gas pipeline compressors
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Migrating industrial networks; Tracking HMI advances; Making the right automation changes
Understanding transfer switch operation; Coordinating protective devices; Analyzing NEC 2014 changes; Cooling data centers
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role that compressed air plays in manufacturing plants.