Questar 3.5″ Telescope Duplex, Magnesium Fluoride Coatings

Description

ooth internal clutch made from micro-rolled discs of stainless steel lets you move the telescope at will. The large setting circles are not merely painted on, but are engraved and then paint-filled, to remain visible even after years of use. ‘Jewel-like precision’ may be an overworked term, but it’s the only one that does justice to a Questar.

Plug a Questar Duplex into a 110 volt 60 Hz household AC outlet and its built-in motor drive smoothly tracks the Moon, planets, star clusters, galaxies, and a host of other deep space objects across the heavens for you, keeping them centered in the eyepiece all night long. During the day, the Duplex will also track the Sun, allowing you to observe sunspot patterns. You’ll do it in complete safety, as standard equipment glass solar filters for the optical tube and finder provide complete protection against the Sun’s fierce radiation for your eye and telescope.

An optional Powerguide III DC drive system and drive corrector will power the Questar Duplex drive motor for up to 50 hours from a single 9 volt transistor radio battery, freeing you forever from the need to stay near an AC outlet to observe the skies. Pushbuttons on the quartz-controlled Powerguide III hand control allow single axis guided astrophotography with drive corrections at 1.4x and 10x the sidereal rate. Other buttons control a built-in map light and the brightness of an optional illuminated reticle guiding eyepiece, and select either a lunar or sidereal drive rate. Another button selects northern or southern hemisphere operation, allowing you to use the Questar anywhere in the world without having to worry about finding the proper power frequency or voltage. With a Powerguide III, the Questar is truly a universal use anywhere/use anytime telescope!

High transmission magnesium fluoride coatings for high light transmission on both sides of the BK7 corrector lens are standard on a Questar Duplex. Having higher transmission broadband dielectric multicoatings added to the corrector lens during manufacture (which also includes a change of mirror coatings from aluminum to silver) is an option worth considering. This option gives you a total of 22% greater light transmission for deep space viewing and low light terrestrial observing, and higher lunar, planetary, and photographic contrast. (Broadband coatings are not recommended if you live by the seaside, as the silver mirror coatings can be adversely affected by constant exposure to salt air.)

A thermally-stable Zerodur ceramic mirror is also available as a factory-installed option to replace this Questar Duplex’s Pyrex mirror to reduce the need for minor refocusing during large temperature swings. As with any Pyrex mirror telescope, if the difference in temperature between indoors and outdoors is 30 degrees Fahrenheit or more when a Questar is taken outside, minor refocusing will be required as its mirror contracts while cooling down to the outdoor air temperature. Although the 3.5″ mirror of the Questar cools down much more rapidly than a larger mirror, some people find the need for even an occasional refocusing to be annoying. Since a Zerodur mirror exhibits virtually no expansion or contraction as temperatures change, this option eliminates the need for refocusing, should this be a concern.

This Questar is protected by a ten-year Questar warranty (two-year warranty on the focuser mechanism).

Absolutely pinpoint resolution, total freedom from spurious color and distortion, with an image clarity and contrast in a class all its own, plus the multifunction ability to convert in seconds from an astronomical telescope to a terrestrial spotting scope and telephoto lens – this Questar Duplex is not only the “Rolls-Royce” of telescopes, it is the “Swiss Army Knife” of telescopes. If you want the best and most flexible small telescope in the world, the Questar Duplex is it. Period.

Tech Details:

Supplied Accessories:

• 1.25″ 16mm and 24mm eyepieces (54x to 120x, depending on eyepiece and whether built-in 1.5x Barlow is used)
• Built-in 4x finder (6x when 16mm eyepiece is used)
• Aluminized and overcoated pyrex mirror
• Magnesium fluoride coated optics
• Built-in star diagonal
• Dual arm fork mount
• Quick disconnect optical tube with built-in photo tripod adapter for terrestrial use
• Setting circles (r. a. circle power driven)
• Sidereal rate AC motor drive (2.7 watts)
• Manual slow motion controls
• Thread-in dust cap
• 1.5″ aperture off-axis solar filter
• Solar filter for finder
• Tabletop tripod legs
• Locking hard case
• Self-storing dewcap with embossed star chart
• Embossed Moon chart on scope barrel
• Ten-year warranty (two years on drive and focuser).