- My experience using two 80-millimeter long-focus refractors
- GSO 8-inch TRUE CASSEGRAIN
- Celestron Regal 65ED M2
- Review: The Vixen FL55ss
- PrimaLuceLab Eagle Review
- interstellarum Deep Sky Guide Desk Edition
- Chronicling the Golden Age of Astronomy: A History of Visual Observing from...
- Omegon Mini Track LX2 Review
- Review of the APM 152 ED serial number 245
- THE BURGESS 24MM MODIFIED ERFLE & 10MM ULTRAMONO
- APM 140mm DOUBLET APO REFRACTOR
- Comparison of the Boltwood II and Sky Alert Cloud Sensors
- Chile Dilly!
- MONO & BINO VIEWING WITH THE BAADER MORPHEUS 17.5MM EYEPIECE
- The Eye of the Flak (Das Auge der Flak)
CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.
Dec 09 2014 03:16 PM | Mike I. Jones in Technical Reports
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.
Oct 14 2005 03:32 PM | CN_Admin in Technical Reports
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.
Mar 22 2005 11:41 AM | EdZ in Technical Reports
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
Mar 22 2005 11:32 AM | Guest in Technical Reports
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