Posts Tagged ‘Telescopes’
Last Updated on Thursday, 12 August 2010 06:11 Written by Administrator Thursday, 12 August 2010 06:11
Unusual Telescopes
In this book, Peter Manly surveys more than 150 unusual telescope designs. These are telescopes built by amateur and professional astronomers to suit some special need. There is, for instance, an inflatable telescope and one with a liquid mirror. Every so often a neglected design comes back into fashion: the largest telescopes now under construction use the alt-azimuth design that was ignored for over a century, and liquid mirror telescopes can be used for zenithal astronomy. The author shows why a particular engineering approach makes each telescope unique and explains the rationale behind the design. The effects on telescope performance are discussed where possible. This is not just a collection of weird and wonderful devices that proved to be false starts; the author also discusses the first instrument to measure star diameters and the first useful radio telescope. This book is a resource and stimulus for anyone who likes to build astronomical telescopes or is interested in the history of telescope-making.
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Tags: Telescopes, Unusual | Posted under Telescope Book Reviews | 2 Comments
Last Updated on Friday, 23 July 2010 12:04 Written by Administrator Friday, 23 July 2010 12:04
Question by xxfoundthewayxx: Why do infared telescopes have to worry about thermal radiation from there surroundings?
Telescopes functioning at visible wavelenfths don’t have to worry a bout thermal radiation from their surroundings, but infared telescopes do; infared detectors are usually cooled by liquid nitrogen or liquid helium. Why?
Best answer:
Answer by Jason T
Thermal radiation *is* infrared radiation, that’s why. Not cooling an infrared telescope would be like having an optical telescope made of luminescent materials in a floodlit football field! You’d never see anything through the light already pouring into your eyepiece.
The body of the infrared telescope itself can absorb the infrared radiation and then re-emit it as it warms up. The detector would be overwhelmed by its own infrared emissions and would be unable to detect distant sources. By cooling it with liquid nitrogen or helium you prevent the telescope itself from emitting infrared, and so it can distinguish distant sources.
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Tags: about, from, infared, radiation, surroundings, Telescopes, there, thermal, worry | Posted under Telescope Questions | 1 Comment
Last Updated on Wednesday, 21 July 2010 04:31 Written by Administrator Wednesday, 21 July 2010 04:31
The Design and Construction of Large Optical Telescopes
This book assembles for the first time in a single text the full range of astronomical and engineering principles used in the design and construction of large telescopes. It aims to cover all aspects of the field, from the fundamentals of astronomical observation, to optics, control systems, and structural, mechanical, and thermal engineering, as well as such specialized topics as site selection and program management. The book is the result of the collaboration of many leading astronomers, engineers, and project managers. Their contributions have been edited to provide a consistent approach and treatment: for example, ground- and space-based telescopes are treated from a common perspective. Topics covered include: – Design Methods and Project Management – Telescope Optics – Stray Light Control – Structure and Mechanisms – Pointing and Control – Active and Adaptive Optics – Thermal Control – Integration and Verification – Observatory Enclosure and Siting
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List Price: $ 129.00
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Tags: Construction, Design, Large, Optical, Telescopes | Posted under Telescope Book Reviews | 1 Comment
Last Updated on Monday, 19 July 2010 10:13 Written by Administrator Monday, 19 July 2010 10:13
Question by lapis: What is approximately the greatest distance out to which it is possible for ground-based telescopes to measure
What is approximately the greatest distance out to which it is possible for ground-based telescopes to measure parallax? Also, why does such a limit on parallax measurements exist?
Best answer:
Answer by Mmkeita K
i dont no
Know better? Leave your own answer in the comments!
Tags: approximately, distance, greatest, groundbased, measure, possible, Telescopes | Posted under Telescope Questions | 2 Comments