Questar 3.5″ Telescope Duplex, Magnesium Fluoride Coatings, Factory Installed Powerguide III

Description

Observe through a Questar, and you’ll appreciate the attention to detail even more. The gearless 25:1 ratio slow motion controls operate with a smoothness and freedom from backlash unmatched by any other amateur telescope. The drive gear diameter is fully half the length of the telescope itself, for tracking precision that must be experienced to be believed. No tiny levers need be thrown to disengage the drive for manual operation, as a butter-smooth 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.

A Questar Powerguide III DC drive system/drive corrector is factory-installed into this Questar Duplex. It replaces the AC motor and 110V power requirement of the standard Duplex. The Powerguide III has a DC servo quartz drive that powers the scope’s drive motor for up to 50 hours from a single 9 volt transistor radio battery. This frees you forever from the need to stay near an AC outlet to observe the skies. The Powerguide III 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 Questar will also track the Sun, allowing you to observe sunspot patterns. You’ll do it in complete safety, as standard equipment glass solar filters provide complete protection against the Sun’s fierce radiation for both your eye and your telescope.

Pushbuttons on the quartz-controlled Powerguide III hand control allow single axis guided astrophotography with 1.4x and 10x sidereal guiding rates in right ascension (dual axis with an optional declination motor). 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 Duplex anywhere in the world without having to worry about finding the proper power frequency or voltage, or having the right kind of AC adapter. With the factory-installed Powerguide III, the Questar Duplex is truly a 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 DC-powered 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).