- COUNTING SUNSPOTS WITH A $10 OPTICAL TUBE ASSEMBLY
- Hubble Optics 14 inch Dobsonian - Part 2: The SiTech GoTo system
- iStar Optical’s Phantom FCL 140-6.5 review
- Who’s Afraid of a Phantom: Istar Phantom 140mm F/6.5, that is?
- SHARPSTAR 94EDPH APOCHROMATIC REFRACTOR
- My Losmandy G11T review
- FIELD TEST: THE NOH CT-20 ALT-AZ MOUNT
- SkyTee-2 Alt/Az Mount Review
- SharpStar Askar ACL200 200-mm f/4 astrographic telephoto lens
- A review of the Unistellar EVscope
- Astrotrac 360 tracking platform – first impression
- FIELD TEST: CARL ZEISS APOCHROMATIC & SHARPEST (CZAS) BINOVIEWER
- Omegon 32mm 70º SWA eyepiece review
- Review of iPolar hardware and software for polar alignment
- Review of the Hubble Optics 14 inch, f/4.6 Premium Ultra Light Dobsonian Tele...
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.
May 09 2020 11:33 AM | Larry F in CN Reports
The Art Institute of Chicago is a museum that I have always considered to be one of the best in the world, even though I’m a New Yorker and a member of the Metropolitan Museum of Art. As my wife and I were ambling through one of the American galleries on a visit in 2018, we looked up to see a figure hanging from the ceiling. It was Isamu Noguchi’s 1932 aluminum sculpture Miss Expanding Universe. We are great fans of this artist for his vast and brilliant output that includes such diverse works as portrait sculptures, furniture (we have a Noguchi-designed coffee table our living room), fountains, monumental abstract sculptures and vast garden installations.
Apr 01 2020 07:51 AM | Larry F in CN Reports
One of the great things about astronomy is how it connects you to so many spheres of human thought and activity, both scientific and cultural. You never know when some unknown link is suddenly revealed, and you learn something remarkable. My latest “astrocultural” discovery was at the Museum of Modern Art, which in the fall of 2017 exhibited a large selection of its extensive holdings of works by the prolific German surrealist artist Max Ernst (1891-1976).
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.