"Telescope Talk: Orion's Eyes"
I'm not a telescope salesman: I'm just a guy who likes looking at the great stuff out there in the heavens. But, here's what I can tell you about a really nice little instrument: the Orion ED 80 refractor.
Background: ED stands for "Extra-low Dispersion," meaning a special type of glass which focuses light better than the plain soda glass used in most small telescope lenses. The problem faced by everyone from famous first telescopic astronomer Galileo, to Joe Average in this century, is that colors focus at slightly different places when coming through a lens system. This means that violet, red, and green light hit the lens at slightly different places, making chromatic aberration or "false color" a problem in refractor (lens only, no mirrors) telescopes. This typically means you'll see a fuzzy violet-colored ring around really bright celestial objects like the Moon, Venus, Jupiter, and brightest stars, like Sirius. Opticians and engineers have tried many different glass lens combinations to help get rid of false color, usually using two or three main lenses up front to refocus the different colors, and diminish the effect. This produced the achromat, meaning "almost no false color." ED glass is one of the most common modern solutions to the color problem, but more expensive than plainer optical glass, so a telescope using it costs quite a bit more money. Telescopes using ED or expensive glass like fluorite are called apochromats, meaning: "Now we're serious, this really has no false color." Honestly, false color doesn't bother everyone. I spent three years observing with an inexpensive 102mm Meade achromat, and my views of the Moon and planets were good quality and very enjoyable, despite the fuzzy purple halo. However, being a bit of a technophile, I always like to try new equipment, and I didn't mind the idea of an improved small telescope. But, when you had US $500 to spend on a telescope, and not US $1500, an ED model just wasn't much of an option, until recently.
The Synta Company of China introduced the ED 80 (80 mm or 3.1 inch diameter objective lens) refractor in 2003, and Orion Telescopes and Binoculars Company, California, U.S.A, is the major North American distributor of this model. In late 2003, Orion originally priced the telescope at US $429! This price was for the telescope tube itself, and not the fully equipped set-up with mount, tripod, finder scope, and star diagonal shown (photo, left). The idea was a true bargain apochromat (hereafter "apo"), that more amateur astronomers could afford. You could buy the higher quality optical tube, and use your existing mount and accessories. Well, this product caused a huge buzz in astronomy circles, and Orion and their dealers sold out in a hurry. The ED 80 was such a hit, the company had it on backorder for anywhere from a few weeks to two months. Plus, by January 2004, Orion raised the price to US $499 - based the old supply and demand from basic economic theory. But, even at that price, this is a really super deal! I received the scope from Orion in January 2004. It is mounted on a Meade LXD-500 German Equatorial Mount (GEM), and has been retrofitted with sturdy set of Al's Oak Legs.
I've had this scope for two months as of this writing, and have been out for six extended viewing sessions, so I have a pretty good basis for saying "This f/7.5 600mm focal length wonder lives up to its name!" Not a trace of false color on Jupiter, Saturn, or bright stars! Images are crisp, have excellent contrast, and focus to a fine sharpness in good seeing (a calm atmosphere without wiggling air, which makes for blurry images). I mainly use the scope at magnifications ranging from 48x to 125x, though it can take up to 150x without any noticeable image degradation. As for the views, they are incredibly bright and detailed -- Aimed at the Moon, this scope shows splendid craterlet detail on major crater floors, and very dark shadows crossing bright white mountain peaks. The King of Planets, Jupiter looks tack sharp, with the two prominent cloud belts visible, and some bubbly detail in the polar cap. I can easily observe the Great Red Spot, and its surrounding atmospheric hollow, and I can also see details such as large dark areas called barges, in the main cloud belts. Turning to the other great gas giant planet: Saturn is beautiful, with fine color distinction, and razor-edged transitions from the glorious rings to the planet. I can easily make out the dark groove of the Cassini Division in the ring plane, and at least one major copper-colored belt on the planet's disk. Heading outward to deeper space, the Great Orion Nebula is a treat, and the multiple star system at its heart, the Trapezium, is as neat and tight and angular as I can recall in a refractor! Nothing but splendid things to see in this scope. If it has a fault, it's merely the small objective size - which every amateur astronomer will tell you is the main tradeoff of a high quality refractor, you just don't get the light grasp of a bigger lens or mirror. As for portability, this scope is pretty light, at about 5.5 lbs/or 2 kg. I can pick up the whole setup and be observing in just a few minutes. I haven't yet attached my digital camera, but I'm certain the scope will produce beautiful prime-focus images.
This instrument is truth in advertising. The Orion ED 80 is a superb quality, well-built small scope, and is perfect for solar-system explorers who want a value-priced apo. You'll be pleased at what you see. -- JW