SUNSET: 
How Can I Prevent My Finder From Dewing Over?
How do I keep my finder from dewing over when I observe? Your finder should have a light shield (“dewcap”), which you can cover between uses. Or you can purchase an anti-dewing device. This need not be expensive. You probably have a box full of them at home: A simple…
Should I wear eyeglasses while observing?
Should I wear eyeglasses while observing? If you are near-or farsighted, with no other eye problems, definitely take them off. You’ll have to tweak the focus, but you’ll see objects in the telescope just as clearly as if you had 20:20 vision. By taking off your glasses you’ll avoid the…
What’s the difference between nebula filters and light-pollution filters?
What’s the difference between nebula filters and light-pollution filters? Nebula filters block out most of the visible spectrum while transmitting the handful of finely tuned colors that emanate from the most luminous constituents of cosmic gas clouds: hydrogen atoms and oxygen ions. Light-pollution filters, by contrast, are designed to block…
What's the difference between two Plössl eyepieces?
I bought exactly the same Plössl eyepiece that a buddy has, but mine doesn’t work as well as his. Did I get a lemon? That’s possible, but very unlikely. Our guess is that your telescope has a short focal ratio, perhaps f/5 or less, while your friend may have an…
Is software available to analyze optical designs of telescopes?
Does software exist, preferably downloadable from the Internet, that I can use to analyze original optical designs of telescopes? Yes. The easiest way to find what’s out there is with a fine-tuned Google search. Right now, if you enter “optical design software” as the search terms, you get a few…
What size first telescope mirror should I make?
What size is best for someone’s first attempt at making a telescope mirror? Most books on telescope making recommend starting with either a 6- or an 8-inch mirror, and that’s good advice. Either size is suitable for a first-timer, but a 6-inch will probably take a little less time to…
If stars appear as points, why are some stars big and some small in different images?
If stars are unresolved points, even in the largest telescopes, why do bright ones look bigger than faint ones? Our eyes are amazing instruments, but they’re limited by physics and biology. When starlight enters an optical system with a circular aperture, such as a telescope or a human eye, the…
Roger W. Sinnott
Roger came to Sky & Telescope in 1971, after gaining an astronomy degree from Harvard University and making two deployments to Southeast Asia as an officer in the US Navy Seabees. From 1974 to 1998 he conducted the magazine's Telescope Making department, showcasing homemade telescopes, accessories, and cutting-edge optical designs.…
Sean Walker
Sean Walker joined the staff of Sky & Telescope in 2000. A graduate of Massachusetts College of Art, Sean brings extensive experience with digital image-processing techniques, as well as decades of visual observing. A self-described "gear head," he is constantly testing out or trading astronomy equipment. Rather than concentrating on…
Alan Dyer
Alan Dyer is one of Canada's best known popularizers of astronomy, and is a veteran of numerous total and annular solar eclipses. His special interest in amateur astronomy is astrophotography of all types from nightscapes on film to deep-sky portraits on CCDs. Alan is author or co-author of several astronomy…
Astronomy Education Links
Organizations Astronomical League Observing Programs Youth ResourcesAstronomical Society of the Pacific (ASP)Astronomy Education ReviewCampaign for Dark SkiesChallenger Center for Space Science EducationChallenger Space Science Center of ArizonaDark-Sky SwitzerlandEuropean Association for Astronomy EducationEuro Space Center (Belgium)International Association for Astronomical Studies (IAAS)International Dark-Sky Association (IDA)National Space Society (NSS)Near and Far Sciences for…
Image & Animation Links
Research Institutions Anglo-Australian Observatory ARC Telescope Astronomical Institutes of the University of Bonn Big Bear Solar Observatory European Southern Observatory Great Images in NASA Harvard-Smithsonian Center for Astrophysics Hubble Space Telescope Institute for Astronomy NASA's Observatorium Image Gallery NASA's Planetary Photojournal Nordic Optical Telescope Ohio State University Astronomy Dept. Stardial…
Astronomy Software Vendors
Contact information for commercial developers of astronomical software.
Robert Naeye
Courtesy Robert Naeye. Robert Naeye was editor in chief of Sky & Telescope magazine and SkyandTelescope.com from 2008 to 2014. It was Bob’s third stint at S&T. He served as an editorial intern during the summer and autumn of 1991, when he was finishing his master’s degree in science journalism…
Good Lighting Fixtures: Where to Get Them
Here's a selection of manufacturers and suppliers of good lighting equipment.
Online Data and Catalog Links
Astronomical Data Center (ADC) Astrophysical Data System (ADS) Canada Astronomical Data Center (CADC) Digitized Sky Survey Double Star Library JPL's Solar System Dynamics Group NASA/IPAC Extragalactic Database (NED) National Space Science Data Center (NSSDC) NGC/IC Project Planetary Data System (PDS) SkyView Solar Terrestrial Dispatch Star Data Pages Strasbourg Astronomical Data…
Amateur Research Societies
The Amateur Sky Survey (TASS) American Association of Variable Star Observers (AAVSO) American Lunar Society Association of Lunar & Planetary Observers Astronomy and Astromicroscopy Center for Backyard Astrophysics Dutch Meteor Society Galilean Satellite Eclipse Timings Grup d'Estudis Astronomics (Spain) International Amateur-Professional Photoelectric Photometry (IAPPP) International Meteor Organization International Occultation Timing…
Professional Research Links
American Astronomical Society (AAS) American Meteor Society Astrophysical Institute of the Canary Islands Berkeley Illinois Maryland Association (BIMA) Brown University Planetary Geology California Space Institute Canadian Space Agency Meteorites and Impacts Advisory Committee Canadian Institute for Advanced Research Central Bureau for Astronomical Telegrams (CBAT) Harvard-Smithsonian Center for Astrophysics (CfA) High…
Online Star Charts
SkyandTelescope.com's Interactive Sky Chart AstroImage AstroViewer Hawaiian Astronomical Society's Storybook and Deepsky Atlas Heavens Above National Geographic's Star Chart Nearest and Brightest Stars in VRML Sky View Café Project DeepSkyMap StarGazer Java atlas Starchart Map Server Skymaps.com Weather Underground Sky Chart
Magazines and Journals
Amateur Astronomy Magazine Astronomical JournalAstronomical Review Astronomie Heute (German language) Astronomy Education Review Astronomy Now Astrophysical Journal and Astrophysical Journal Letters Australian Sky & Telescope Coelum (Italian language) EurekAlert! science research news server Icarus Journal of the British Astronomical Association Mercury Meteorite! Nature The Planetarian Popular Astronomy Publications of the…
