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