Others will opt for glass-based white-light filters, which can be found in so-so entry-level quality for as little as $70US, but the price of which climbs drastically when the glass substrates approach 1/20-wave precision. Having experienced it, some of the thousands who see the Sun for the first time through the equipment I carry will invest in Hydrogen-alpha telescopes capable of approaching the thrilling detail produced by the DayStar Quark, despite that the entry point of Hα is around $600US and climbs quickly from there. It doesn’t take long for them to wonder whether they, too, can convert their sporting optics or telescopes into solar scopes.Īnd as I explain the options, the next inevitable question is, “What does that cost?” Reactions to each answer remind inexpensive to those of us who enjoy astronomy daily may not feel as affordable to those whose current interest in astronomy is still limited to a one-time viewing of the Augeclipse. A surprising number even recall astronomical telescopes hidden away in closets and garages.
When I explain to guests that both the Sky-Watcher Mak and Explore Scientific apo can be used for nightsky and daylight terrestrial viewing and imaging, as well as for solar, many are reminded that they already own binoculars or spotting scopes. Image 3 – The second cardboard ring was drawn using the first as a template, then also cut out with a utility knife. The solar equipment I currently carry include a Sky-Watcher USA 90-mm Maksutov- Cassegrain fitted with a factory-made solar-film filter, Lunt Solar System’s 8×32 (white-light) SUNoculars and an Explore Scientific ES80CF mated with a DayStar Quark (Hα). White-light and Hydrogen-alpha, it’s a rare day that I’m not asked about affordable solar-viewing and -imaging options. With the Great American Eclipse looming upon us, I’m regularly sharing views of the Sun in both By passing only the Hα wavelength and rejecting the rest, we’re able to observe and photograph detail that is hidden in the relative intensity of rest of the solar spectrum, such as solar prominences. Instead, they are designed to deliver only a very narrow slice of that bandwidth, such as the Hydrogen-alpha wavelength centered at 656 nanometers.
#HOMEMADE SUN SPOTTER TELESCOPE FULL#
Narrowband solar filters do not deliver the full spectrum of solar light. Image 2 – Cutting the first cardboard ring with a utility knife. Baader Planetarium also produces a Herschel Prism, which, for point of reference, Astro-Physics lists for $710US. There are exceptions, though, such as Herschel Prisms, also known as Hershel Wedges, that are placed between the telescope and the eyepiece through which you view or the camera with which you image. That is the type of whitelight filter covered by this article. The simplest white-light filters mount in front of the telescope, where they can reduce that intensity before the sunlight enters. Although white-light filters pass the fullest breadth of the spectrum of solar light, they reduce the intensity of that full spectrum significantly.īaader Planetarium’s AstroSolar material, which is the subject of this article, has a light reduction factor on the order of 100,000 times, and it is that intensity reduction factor that allows us to safely view the Sun through a telescope. Add back that blue, and you have the definition of white. We see the Sun as yellow only because our atmosphere scatters much more of the blue wavelengths.
Broadband solar filters are called broadband or more specifically, white-light filters, because they pass the broadest spectrum of light emitted by the Sun, which appears white. Ultimately, the 90-mm circle was used to define the aperture rather than the 80- mm, and the square was unnecessary, too.įor those of you who are new to all this, solar filters are of two basic types: broadband and narrowband. If 1/20-wave precision is your goal, when it comes to glass, expect to pay dearly for it.Ī Brief Explanation of Solar Filters Image 1 – A compass was used to draw concentric circles on stiff cardboard with diameters of 80 mm, 90 mm and 152 mm. At the other end of the glass-substrate spectrum, those fashioned using high-quality optical- grade glass produced excellent views but at prices that reflected their excellence. Of course, those with coatings deposited on inexpensive plate glass were, well … inexpensive, but they also delivered poor views. I’ve used many white-light solar filters over the years, including examples made with glass ranging from poor to excellent in optical quality. By Gary Parkerson, Executive Editor Astronomy Technology Today