Bushnell Telescopes

More Information  · Supplied Accessories  · Related Documents  · Images of Some Features Price $359.95 Shipping $25.00 List Price $565.95 Highest Useful Magnification 180x Visual Limiting Magnitude 12.2 Focal Length 1200mm Focal Ratio f/13.3 Resolution 1.3 arc seconds Aperture 3.5" Weight 13.5 lbs. Warranty 2 years

The Maksutov-Cassegrain design of the 90mm (3.5") aperture optical system has two visible benefits. First, it eliminates the purple halo of spurious color common with refractors in this size range. Second, it eliminates the spherical aberration that causes the blurred and slightly out of focus star images often seen in Newtonian reflectors in this price range. The result is an exceptionally sharp and high contrast image that is unsurpassed for observing lunar and planetary details, and for resolving binary stars and globular star clusters.

It’s hard to believe that you can get this level of performance for so little money. Nevertheless, it’s true. This truly inexpensive (but optically exceptional) telescope finds objects in the sky for you automatically at the touch of a button. In addition, a human voice talks you through the telescope setup and operating procedures and describes each celestial object as you view it. If the idea of a talking telescope doesn’t appeal to you, you can always turn off the Real Voice Output and observe in silence.

The easy-to-use 90mm NorthStar is light enough to pick up in one hand and carry to your observing location, whether that’s your own back yard or a distant site away from city lights. Once you’re there, place the telescope on its supplied adjustable height field tripod; do a quick, easy alignment of the telescope’s computer to the sky; and start observing. It’s that simple. If you can tell the telescope the day and the time, the name of the closest big city, and where North is, the 90mm NorthStar will locate planets, stars, and deep space objects for you at the push of a button. Once found, it will follow those objects automatically as they move across the skies so you can observe at your leisure.

All of the major planets except Pluto can be seen with exceptional clarity and detail through the BNS90. You can study the multiple rings of Saturn; the cloud belts and four major moons of Jupiter; and the polar caps and prominent features on Mars. You can see mountain ranges on the Moon, rilles and domes, and lunar craters by the hundreds. Within our Milky Way galaxy the NorthStar will find and let you view hundreds and hundreds of nebulas; star clusters; double, multiple, and variable stars; plus dozens of external galaxies – as many as 20,000 stars and celestial objects in all. Not all of the faint deep space objects will be easily visible, due to the relatively small aperture and long focal ratio of the scope, but the NorthStar still reveals an amazing amount of celestial detail that is invisible without the telescope.

This Telescope’s Optical System . . .

Compound optical design: 1200mm focal length 90mm aperture f/13.3 all-glass optics. Maksutov-Cassegrain optical design using a lens and two mirrors to fold a long 47" focal length optical system into a compact optical tube that’s barely 10" long.

Finderscope: The supplied battery-operated non-magnifying red dot finder attaches to the side of the optical tube. It seems to project a dot of red light on the sky exactly where the scope is pointed at all times. It makes initial scope alignment and object centering easy and painless.

Two multicoated eyepieces: You get a high power 1.25" 4mm (300x) eyepiece and a medium power 1.25" 25mm (48x). The 300x magnification of the 4mm eyepiece is realistically beyond the maximum practical magnification limit of a 3.5" scope under all but the most exceptional seeing conditions. Do not expect to be able to use the 4mm eyepiece on an everyday basis. An optional 6mm to 9mm high power eyepiece would be more useful on a night in/night out basis.

This Telescope’s Mount . . .

Fork mount/drive system: The 90mm NorthStar has a very stable single arm fork mount with two built-in motor drives. Precision drive systems on each axis permit smooth pushbutton operation of the telescope using the supplied computer hand control. A single 9-volt transistor radio battery (not supplied) in the drive base powers the NorthStar.

RVO computer: The RVO (Real Voice Output) computer hand control that store in the base of the telescope makes initial setup of the scope easy. Simply point the optical tube north and follow the few short instructions on the hand control’s two-line red illuminated LCD readout – or follow the verbal directions of the teeny, tiny human being hiding in the hand control (just kidding, the computer is only playing back a recorded human voice). Once it’s aligned on the skies, a procedure that takes only a few minutes, the computer lets you automatically locate and precisely track over 20,000 stars and celestial objects. Just choose the object you wish to observe on the hand control display. The display will show you how far and in what direction to move the scope to get to the object. If you prefer, simply press the GO TO button, and watch as the telescope rapidly moves all by itself to place the object in the field of view. Once centered on an object, the computer display will tell you about the object and the Real Voice Output will verbally repeat the information so you don’t have to take your eye away from the eyepiece to learn about what you are seeing. You can always turn the voice output off at the touch of a button if you’d prefer to observe in silence. If you don’t know what you’d like to look at, you can have the computer take you on an automatic guided tour of the best objects visible on the night you observe. The hand control shows a constantly updated display of the celestial coordinates (right ascension and declination) that the scope is pointing to, plus the terrestrial coordinates (altitude and azimuth).

Tripod: The supplied field tripod is rigid and stable for shake-free high-power astronomical observing. The lightweight aluminum tripod permits altazimuth (vertical-horizontal) alignment of the telescope and easily adjusts for standing or seated observing. The tripod includes an accessory shelf that holds your eyepieces.

Lifetime warranty: NorthStar optics and mechanics are protected by a lifetime Bushnell warranty (electronic components are covered by a two-year warranty).

If you add up all that you get – the 90mm Maksutov optics telescope, the battery-operated motor drives, the two supplied eyepieces, the RVO go-to computer, and the full length adjustable height field tripod – you have a telescope that was unavailable to the amateur astronomer at any price only a few short years ago. The fact that the 90mm NorthStar exists, that it works so simply and so well, and that it costs so very little for all the performance and features you get, is a marvel indeed. For the beginner, as a gift for an inquisitive youngster, as a second or travel scope for the advanced lunar and planetary observer, the 90mm NorthStar is well worth serious consideration.