Junk.
Written: Jun 16 '00
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Product Rating:
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Pros: None
Cons: Unusable
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| ke8yy's Full Review: Bushnell Voyager 78-9440 (440 x 12.5mm) Telescope |
Most prospective buyers of telescopes think that magnification is what they should be looking at. Makes sense; after all, you're looking at something millions of miles away. But oddly enough, magnification is the last thing you should consider.
The most important aspect of a telescope is aperture, or the size of the objective lens- that's the big lens at the end of the telescope. Your eye is only 6mm or 7mm in diameter at its widest, and a 60 mm lens, like the one on the scope under review, can gather over 100x as much light as the typical eye. That's important. It allows you to magnify a small image without it becoming too dim to see.
Back to magnification: There's a limit, for any given scope, of how far you can magnify the image before it becomes impossible to see, because of the limitations of the scope and the eye. For a telescope with excellent optics, that figure is generally around 50x per inch of aperture under ideal conditions. For a 60mm scope (about 2-1/4"), that works out to just over 100x. Best resolution with a scope this size is had at around 40x.
But this scope is advertised as having a magnification of 400x. How can they do that? Answer: They can't. It's physically impossible. They supply you with cheap eyepieces that theoretically deliver 440x- but if you try to actually use them at that magnification, all you'll see is a dim blur. In other words, they're selling something that they know is unusable, since they realize naive consumers will buy based on the magnification.
Recommendation? Skip this turkey, and all other telescopes sold in department stores. Stick with telescope specialist dealers. You can still get a usable scope for $100 or $200- just not this one.
Recommended:
No
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Epinions.com ID:
ke8yy
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Member: Michael Edelman
Location: Huntington Woods, MI
Reviews written: 85
Trusted by: 3 members
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