Features

This is an excellent and very compact computerized telescope.

Product Highlights

• 90mm/3.5" Maksutov-Cassegrain
• Focal Length: 1250mm f/13.9
• 9.0mm Eyepiece
• 25mm Eyepiece
• Stainless Steel Tripod w/ Accessory Tray
• Computerized Altazimuth Mount
• StarPointer Finderscope
• 'The Sky' Level 1 CD-ROM
• NexStar Observers List CD-ROM
• NexStar Computer Control technology

Overview

Designed as an affordable computerized 'Go-To' telescope, the NexStar 90SLT telescope from Celestron provides an excellent balance of power, performance, and portability. With its computer-automated technology, the SLT is up and running after locating 3 bright celestial objects.

This SLT is a Maksutov-Cassegrain reflector with a 90mm aperture and a focal length of 1250mm. The optical system is fully coated for enhanced sharpness and clarity. Two eyepieces are included - one 25mm as well as a 9.0mm. The mounting platform incorporates a sturdy stainless steel tripod with a motorized and computerized altazimuth mount.

An Altazimuth Mount is a simple two-axis mount for supporting and rotating an instrument about two mutually perpendicular axes; one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth (compass bearing) of the pointing direction of the instrument. Rotation about the horizontal axis varies the altitude (angle of elevation) of the pointing direction.

New and experienced observers will appreciate NexStar 90SLT's comprehensive database of 4000+ objects, along with the customized lists of the most intriguing deep-sky objects, planets, and double stars.

Combining a first-class feature-set with Celestron's legendary optical standards, the 90SLT provides amateur astronomers with a sophisticated and easy-to-use telescope. The computerized hand-control provides simple on-screen instructions that guide the observer through the alignment procedures. Each step, helpful hints, and valuable reference materials are easily accessible to ensure a simple and pleasurable viewing experience.

NexStar 90SLT Telescope

• Maksutov-Cassegrain reflector
• Aperture: 90 mm/3.5"
• Focal Length: 1250 mm, f/13.9
• AFOV: 1.0°, LFOV: 53' @ 1000 yd
• Optical system: all-glass, fully coated
• 2 Eyepieces: 25 mm - 50x, 9.0 mm - 139x
• StarPointer finderscope for accurate alignment and object location

Motorized Altazimuth Mount

• Lightweight computerized altazimuth mount
• Fully enclosed motors and optical encoders
• Fully adjustable sturdy stainless-steel tripod
• Flash upgradeable fully computerized hand control
• Internal battery compartment to prevent cord wrap during use
• Educational astronomy software CD-ROM "The Sky" with printable sky maps
• Quick-release fork arm mount, optical tube, accessory tray for quick no tool set up
• Hand control and motors are powered by 8 user-supplied AA batteries or optional 12V AC adapter
• NSOL telescope control software: provides basic telescope control via computer with optional RS-232 cable
• Computerized hand controller with NexStar computer control offers 4,000 object database and storage for programmable user defined objects
• Tracking rates: sidereal, solar, lunar. Tracking modes: alt-az, EQ north/south. Slew speeds: 1,2,3°/sec - 64x, 32x, 16x, 8x, 4x, 2x. Alignment procedures: skyalign, auto 2-star, 1-star, 2-star, solar system.

Maksutov-Cassegrain telescopes are similar to Schmidt-Cassegrains, using both mirrors and a lens to focus light into a smaller area. Maksutov-Cassegrains replace the familiar corrector plate and secondary mirror of the Schmidt-Cassegrain with a convex meniscus lens. The secondary mirror is actually a silvered spot on the inside of the meniscus lens. This in itself leads to one major advantage: Maksutovs do not require periodic collimation of the optics as do Schmidt-Cassegrains and Newtonians.

Maksutov-Cassegrains offer superior contrast to a Schmidt-Cassegrain due to the smaller central obstruction of the secondary mirror. They are suitable for both astronomical and terrestrial observing due to the upright image they produce, and are an excellent choice for planetary and double star observing. The only noteworthy disadvantage to a Maksutov-Cassegrain is the relatively slow focal ratio that results in a narrow field of view in comparison to other optical designs with similar aperture.

Specifications

Optical Design Maksutov-Cassegrain
Aperture 90 mm / 3.5"
Focal Length 1250 mm
Focal Ratio f/13.89
Eyepiece Barrel Diameter 1.25"
Finderscope StarPointer
Mount Type Computerized altazimuth
Tripod Stainless steel
Resolving Power Rayleigh: 1.55 arcsec
Dawes: 1.29 arcsec
Maximum Useful Magnification 213x
Motor Yes
GO-TO Capability Yes
PC Compatible Yes, via RS-232 cable
Power Source 8 AA batteries
Weight 12.0 lb / 5.44 kg