Several of the night sky's showpieces span a degree of more on the dome of the sky and wide-angle, low-power views of the Milky Way are simply stunning. Another virtue of a wide-field telescope is its small size, which makes it likelier to fit into a crowded arpartment or a car chock-full with camping gear. The Astroscan OverviewFor these reasons and more, Edmund Scientific created the Astroscan, a stubby, red reflector with a 4.25 inch f/4.2 primary mirror encased in a round plastic ball. The ball sits in a felt-lined cradle, allowing the Astroscan to be aimed at any point on the sky with a gentle push. For much of its quarter-century+ tenure, the Astroscan stood alone. Some of the Astroscan's unique and best features include:
The Astroscan is an "ideal first telescope for (the) entire family." For most families, that means the telescope has got to be extremely simple to assemble when it comes out of the box. And indeed, the Astroscan is. You can unpack the Astroscan and set it up in less than five minutes. Edmund ships the Astroscan with a planisphere and a thorough beginner's guide to amateur astronomy. Astroscan versus the Bushnell Voyager Model 78-2010I first compared the Astroscan and the Busnell Voyager on a breezy summer night with excellent transparency, no moon-light and moderate seeing. Both telescopes saw all of the 9th magnitude stars and some of the 10th magnitude stars in the triangular region bordered by Vega, Epsilon Lyrae, and Zeta Lyrae. The Astroscan's eyepiece provided an ever so slightly wider field of view. (But) basically, both 16x views were comparable. It took a lot longer to find my targets with the Voyager because it lacked a sighting device. I was forced to try lining up the edge of the sphere with the top of the focuser knob. On one night, this trick worked well; on another, I spent a minute or more hunting for Jupiter and Vega. Another annoyance was the gaping hole for the carrying strap in the bottom of the Voyager. This would often catch on the felt pads that line the telescope's base, bringing sky sweeping to a dead halt. Visions of Jupiter(Used with) my own high-quality eyepiece (a Tele Vue 8-mm Plossl) yielding 57x on the Astroscan and 54x on the Voyager, the Astroscan-Tele Vue combination readily showed three cloud bands on Jupiter and even hinted at ruffling on the equatorial bands; "surprisingly sharp" read my notes. By comparison, the Bushnell-Tele Vue combination barely showed even the two most promising stripes. Saturn's rings mainfested themselves crisply in the Astroscan with the gaps between the rings and the globe clearly defined. Would the Bushnell do any better with the Tele Vue eyepiece than with its own? No luck: the ringed planet still appeared an indistinct oval. Astroscan versus the Discovery 4.25" EQLater in September when our Discovery 4.25" EQ arrived, I used it side by side with the Edmund Astroscan. My sketches of the Dumbbell Nebula and its surroundings showed that 10th-magnitude stars faintly visible in the Astroscan were absent from view with the Discovery telescope. I also found the nebula notable dimmer in the Discovery. These findings are hardly surprising given the Discovery's smaller effective aperture. Star- testing the Discovery was difficult; the thick wire struts that support the secondary mirror threw off such bold diffraction features that little could be seen of the disk and rings that one normally uses to probe for abberations. The small plastic-lens finderscope on the Discovery was adequate for finding planets and the very bright stars - but no more. Slewing from place to place was much easier with the Astrocan...the Discovery mount had unusually tacky motions. The Choice is YoursIf you've decided that a 4-inch f/4 reflector is right for you (or the budding astronomer in your life) there is... little reason to choose Bushnell's Voyager model. The Edmund Astroscan's time-tested design is superior, on balance, and its far better optics give respectible views of high-lights like Jupiter's bands and Saturn's rings when mated with an optional 8- to 10-mm eyepiece. Its superlative documentation package will keep a budding stargazer going for many months without having to purchase other atlases or catalogs. The Discovery's effective aperture and resolution are significantly diminished by a too-small secondary mirror. Beginning astronomers with probably need a great deal of help getting it "tuned up" unless the instruction manual is rewritten and adequately illustrated. Astroscan Packages and AccessoriesAstroscan Basic PackageAstroscan Deluxe Package Astroscan Accessories Astroscan Eyepieces
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