Aircraft pilots and aviation students are familiar with the so-called "whiz wheel" or E6B computer, a cardboard or metal analog device that works on the old slide-rule concept. The device dates back to the 1930s; it still handily helps pilots calculate a variety of data including wind speed, fuel consumption, and the like. Of course, there are electronic keypad versions of the E6B available, but many flyers swear by the batteryless cardboard or brushed aluminum slide wheel versions in the cockpit.
Amateur astronomers have similar analog devices to rely on for a variety of tasks, from quick reference to finding stars and constellations. The best thing about such analog devices: no complicated learning curve, they don't require batteries, and you won't be fumbling with a keypad that is designed for a child's tiny fingers.
Most popular among the analog computers for astronomers of all levels are calculating wheels such as the Glow in the Dark Star Finder. This handy cardboard computer, and others of similar designs, help stargazers quickly locate stars and constellations at night. While advanced amateurs know the night sky like the back of their hands, many beginners will find the Star Finder a quick and easy way to gain night-sky familiarity.
In the case of the Glow in the Dark Star Finder, major stars are printed in a non-radioactive luminous ink which glows in the dark (you have to expose the wheel to a light source for a few minutes to activate the luminous ink).
The star finder can be set to show the positions of the stars for any date and time, a.m. to p.m. Star Finders require the user to hold the device overhead with a clearly marked arrow pointing "north" to orient.
Once established, you then rotate the star map wheel so that the date of observation printed on the map corresponds to the hour of observation printed on the map. It's more difficult to explain than to use, believe me. There's also a handy zodiac dial printed on the wheel back.
Another analog device used by astrophotographers is the Whiz Wheel (no relation to the E6B explained above). It's an astro-imaging calculator for film and electronic imaging. It can also be used with a variety of digital cameras such as CCD cameras, even web cams and home video cameras.
Canadian astronomer Gordon Patterson invented this nifty calculator in 1975. But since the 1990s, the Whiz Wheel has been modernized to include exposure settings for digital cameras.
For young astronomers looking for fun, analog learning wheels make all the difference. They are easy to use and provide a great way to access instant facts and figures.
The D.C. Heath Solarscope dates from the 1950s and lists all nine planets. Yes, far-out Pluto is still considered number 9 on the the Solarscope's hit parade, but I suspect future versions will demote Pluto to dwarf planet status.
Set the Solarscope to, say, "Mercury", and it provides you with instant data such as the hot planet's order in size, diameter in miles, approximate mean distance from the Sun, length or day and year, length of time for a one-way radio message to travel from Earth to there, the planet's escape velocity, etc.
Another fun, handy "whiz wheel" for astronomers of all ages is the Moon Gazers' Wheel, created in 2009 by astronomer and educator Bob Crelin.
This cardboard wheel is an easy-to-use guide to understanding the changing faces of the Moon. Set the wheel for when the Moon rises and sets in your town and then you'll be able to instantly calculate the next rising or setting-plus know the Moon's phase. You can also determine, at a glance, if the Moon will be visible or not in the sky in your neighborhood.
If you're interested in buying any of these modest priced analog devices, start with www.powscience.com or search for "star finder wheels" and see what else is available. Moon Gazer wheels may be purchased at the inventor's website: www.BobCrelin.com.
What's in the Sky: On Saturday, July 17,check out Vega is the brightest star in the eastern sky. Deneb is to vega's lower left with Altair to the lower right. This bright trio forms the Summer Triangle.
Lou Varricchio, M.Sc., is a former science writer at the NASA Ames Research Center in California. He is Vermont's NASA-JPL Solar System Ambassador and a recipient of the U.S. Civil Air Patrol's Gen. Chuck Yeager Aerospace Education Achievement Award.