Technical Reports

Thermal Modeling and Athermalization in Telescope Optical Design

Telescopes are typically stored and operated over a wide range of temperatures. Changing temperatures and extreme temperature ranges affect nearly all materials used in constructing telescopes, as well as the optical properties of the air in the immediate vicinity. This article discusses the two principle effects of temperature on telescope materials: (1) changes in optical and structural material dimensions with temperature, and (2) changes in optical glass refractive index with temperature. These two temperature-dependent material properties usually combine to negatively affect optical performance in refractive and catadioptric systems if not compensated for, and system optimization must account for these properties in the design phase to minimize temperature effects on telescope performance.

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Thoughts on Optical Aberrations and simple telescope testing...

Today there seem to be more amateurs than ever getting into the hobby, and like many of us, they are not just interested in the targets in the night sky but the optical systems themselves. Although seemingly simple an optical system is quite a complex thing, with various and confusing elements.

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CN Report: The $50 Pier

An excellent and detailed article on how to build your own Pier.

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CN Report: Affect of Eye Pupil on Binocular Aperture

In a telescope, you can vary the exit pupil by changing the eyepiece. In a fixed power binocular the exit pupil you purchase is the exit pupil you live with. The question answered here is this: What happens when your eye pupil is smaller than the binocular exit pupil

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CN Report: How to clean a Fraunhofer Achromat

Ever wonder how you disassemble and clean an achromat refractor? This article lays out the steps in a clear to understand manner.

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CN Report: Understanding Spherical Aberration

Optical designer Thomas Back explains what spherical aberration is and why you need to know about it

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CN Report: Limiting Magnitude in Binoculars

What exactly is the limiting magnitude of a pair of binoculars? Does it depend on the size? The magnification?

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CN Report: CT-Scan of a Meade 2045 SCT

What does it look like when you put a Meade 2045 SCT through a CT-Scan? The results are fascinating

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CN Report: How to convert a hybrid Newtonian into a good RFT

Ever hear of mirror flexing? If not, you are in for a treat with this article. Carlos takes you step by step through a complete newtonian conversion project

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CN Report: Review of the TMB Mono Reviews

Albert Bellg critiques both his own review of the TMB monos and a recent Sky & Tel review. Did some errors occur?

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