Since high magnification isn’t necessary for casual solar observing, will binoculars suffice? I’d say yes, but I worry about the risk to the optics should binoculars be used for solar projection. If you’d like to observe the Sun with binoculars or simply prefer a direct telescopic view, invest in an aperture solar filter. Made of black polymer, Mylar, or specially coated glass, it affixes to the front of the binocular barrel or telescope, blocking out all but a safe amount of incoming light. Costs depend on type and telescope aperture, ranging from $20 for a black polymer filter suitable for standard binoculars or a 2-inch refractor to over $200 for a glass filter designed for a 16-inch scope. Do-it-yourselfers who wish to construct an aperture solar filter should look into a tutorial posted on the website of the Springfield Telescope Makers. Log on to
http://tiny.cc/stellafanesun.
Small-aperture telescopes manufactured during the latter half of the 1900s were often accessorized with Sun filters that screw into the eyepiece. Don’t use them! Concentrated heat at the eyepiece has caused screw-in Sun filters to shatter without warning. Don’t believe me? My January 2010 column, “Screw-in solar filter hazards,” relates several accounts from readers who were momentarily blinded when theirs suddenly splintered.
Solar projection and aperture Sun filters deliver what is called a “white light” view of the Sun. If you’d like to see our star in a whole new light (literally!), look into a specialized filter or telescope that allows only a narrow bandwidth of light (in this case, the Hydrogen-alpha line of the solar spectrum) to reach the eyepiece. They’re a lot more money — a few hundred dollars to as much as a few thousand — but the visual reward is worth every penny. What could be more breathtaking than to view a solar prominence arching high above the Sun’s limb or to capture a solar flare erupting from the vicinity of a sunspot?
If you’re a dedicated backyard astronomer, don’t limit your quest to the denizens of the night sky. The most magnificent prey of all roams the daytime sky.
Questions, comments, or suggestions? Email me at
gchaple@hotmail.com. Next month: We see the unseen! Clear skies!