- 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.
Jan 14 2020 01:53 PM | CygnusBob in CN Reports
Amateur astronomers have been using lucky imaging for planetary targets with great success. The basic strategy is to obtain a large number of short exposure images in order to “freeze” the turbulence and then select the sharpest images for alignment and integration. Short exposures are valuable because the biggest effect of turbulence for small telescopes is image jitter. For long exposures, the image jitter gets averaged out, just generating a blurred image. The problem with doing this with deep sky objects is that the number of photons collected in a 1/60 of a second is rather small in most cases. This makes it hard to determine an image shift accurately. However lucky imaging can still help sharpen DSO imagery.
Dec 15 2019 12:30 PM | CygnusBob in CN Reports
A paper that describes a method of noise reduction for DSO imagery that I have invented for Deep Sky Lucky Imaging. I am Dr. Robert Majewski, a retired engineer living in Las Vegas. I have M.S. and Ph.D. degrees in Physics from the University of Illinois. My career involved testing and calibrating a number of imaging electro-optical systems at the Hughes Aircraft Company and Raytheon Missile Systems. My hobbies include high resolution planetary imaging, exo-planet transits and deep sky imaging.
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.
Nov 22 2014 02:37 PM | Scott in NC in Other Reports
A. Jaegers Optical Corporation--A personal recollection Stephen L. Nightingale For many teenagers in the 1960’s, an after-school or summer job meant...MacDonald’s! As a teenage amateur astronomer and telescope nut, I had the perfect job--working for Al Jaegers at A. Jaegers Optical Corporation from 1968 to 1970.
Mar 29 2011 05:24 AM | David Knisely in Accessories Reports
I had purchased a QuickFinder to put on the front of the dewcap of my 100mm f/6 refractor, as I was occasionally having trouble getting to the new "correct-image" right angle optical finder I had installed earlier