Used Celestron 7" Maksutov OTA

Condition:

This is a used 7" Mak in excellent condition. The outer body and the optics are both clean, though there is some pretty insignificant dust on the corrector plate of the scope that will not disturb your view at all. Includes the diagonal as well as a 28mm eyepiece and an 8x50 finder scope, all in great condition as well. This does not include the original boxes. 

Description:

The 700 Maksutov-Cassegrain telescope (700 Mak) is a specialized instrument designed for detailed, high contrast views of smaller celestial objects like the planets. With the Maksutov-Cassegrain optical tube and sturdy equatorial mount and tripod, this kit will provide unparalleled views of the planets and up-close views of the lunar surface, including craters and maria, Maks are also well suited to hunting smaller, fainter, deep sky objects such as globular clusters and planetary nebulae.  Astronomers located in urban areas will appreciate the Mak’s ability to bring out more contrast in celestial objects. Transporting the entire system to a dark site is not a problem either. The optical tube, mount head, tripod, counterweight bar, and counterweight all disassemble, with no tools required, into separate manageable pieces.

Maksutov-Cassegrain Optical Design 

The Mak is a catadioptric telescope, which means the optical design includes both a lens and a mirror. The light coming through a Mak passes through the corrector lens to the primary mirror and back to a spherical secondary mirror before it hits your eyepiece. Images are bright, sharp, and virtually free of chromatic aberration.

The Maksutov-Cassegrain’s optical design offers several unique benefits. Instead of a secondary mirror, the Mak features a “secondary spot” of reflective coating applied directly to the inside of the corrector plate. Because of this, the telescope does not require frequent collimation like a Schmidt-Cassegrain. Also, the secondary spot is significantly smaller than a traditional Schmidt-Cassegrain secondary mirror, giving the Mak its signature high-contrast views.

One important thing to note about Maksutov-Cassegrain telescopes is that the larger, heavier Maksutov corrector plate takes longer to cool down and adjust to ambient air temperature compared to a Schmidt-Cassegrain of the same aperture.

StarBright XLT Technology

StarBright XLT is Celestron’s revolutionary optical coating system that outperforms any other coating in the commercial telescope market. There are three major components that make up our StarBright XLT high-transmission optical system design:

• Unique enhanced multi-layer mirror coatings made from precise layers of aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and SiO2 (silicon dioxide). Reflectivity is fairly flat across the spectrum, optimizing it for both imaging and visual observing.
• Multi-layer anti-reflective coatings made from precise layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide). Hafnium—a rare element that costs nearly $2,000 per kilogram—gives us a wider band pass than the titanium used in competing coatings.
• High-transmission water white glass is used instead of soda lime glass for the corrector lens. Water white glass transmits about 90.5% without anti-reflective coatings; that’s 3.5% better transmission than uncoated soda lime glass. When water white glass is used in conjunction with StarBright XLT’s anti-reflective coatings, the average transmission reaches 97.4%, an 8% improvement.