Designed as a highly portable and user-friendly entry- to mid-level astronomical observation platform, the Celestron NexStar 90SLT 90mm f/14 Maksutov-Cassegrain GoTo Telescope gives you the ability to make detailed observations of the Moon, with the ability to easily see planets and reach outside the solar system to resolve bright deep-space objects like galaxies, nebulae, and binary or variables stars. The compact and powerful Maksutov-Cassegrain design uses a front corrector plate with a convex meniscus lens to correct off-axis aberrations, like comas, and chromatic aberration to produce images with true color rendition. The nature of the lens results in a smaller secondary mirror—limiting obstruction and increasing contrast, while eliminating the need for periodic collimation.
The brain of the NexStar SLT is the venerable NexStar computer controller. Equipped with a database of over 4000 objects, including the planets, stars, nebulae, galaxies, and the complete Messier catalog, it can also be programmed with up to 99 custom user-defined objects and filters for custom object lists. Its intuitive menu-driven user interface provides the power to observe the heavens with nine slew speeds and three tracking rates, plus anti-backlash compensation. Features such as guided tours, extended information on 200 popular objects, and multiple assisted alignment procedures make the NexStar controller easy to use and invaluable to new users and experienced stargazers.
Optical Tube
- 90mm aperture
- f/14 focal ratio
- 1250mm focal length
- Maksutov-Cassegrain optical design
- Front convex meniscus lens corrects spherical and chromatic aberrations and comas (off-axis aberration) across the entire field of view
- Compared to Schmidt-Cassegrains, a smaller secondary mirror reduces obstructions and increases contrast
- Fully coated optics improve light transmission, color rendition, and contrast
- Resolution: 1.55 arcsec (Rayleigh); 1.29 arcsec (Dawes)
- Internal focusing system
- Vixen-style dovetail plate
NexStar Controller
- 4000+ object database
- 99 customizable user-defined objects
- Expanded information on over 200 most popular objects including history, facts, and mythology
- Tracking rates: Sidereal, Solar, Lunar
- Nine slew speeds: 2x, 4x, 8x, 16x, 32x, 64x, 1°/sec, 2°/sec, 3°/sec
- Anti-backlash compensation trains out the intrinsic play between gears to improve GoTo and tracking accuracy
- Alignment procedures: Sky Align, Auto 2-star, 1-star, 2-star, Solar system
- SkyAlign allows fast and easy alignment without having to polar align or even know the names of stars
- Tour mode: Seeks out the best objects and automatically slews to them
- Constellation Tour: Tour of the best objects within a specific constellation
- Identify mode: Searches the database catalogs or lists and displays the name and offset distances to the nearest matching object
- Flash upgradable via Internet
- 2-line/16-character LCD display with 19 backlit LED buttons
- RS-232 communication port for updating or computer control
- Database Details:
- Solar system: Includes planets, Moon, and Sun
- Constellations
- 50 named deep-sky objects
- Stars: Select list of SAO catalog including named stars, asterisms, variable stars, double stars
- Abell catalog
- IC catalog
- Caldwell catalog
- Complete Messier catalog
- Select objects from the NGC catalog
Mount and Tripod
- Mount:
- Single-arm fork design
- Dual-axis DC servo motors
- Optical encoders on motors improve GoTo and tracking accuracy; up to 0.26 arcsec accuracy
- Internal battery compartment to prevent cord wrap during use
- Hand control and motors are powered by eight user-supplied AA batteries or optional 12 VAC adapter
- No-tool setup, complete quick release setup and breakdown
- Tripod:
- Sturdy stainless steel
- Adjustable height accommodates a variety of users and observation positions
- Spiked feet improve stability on soft or uneven ground
- Movable hand controller holder prevents cord wrap during long-duration observation and astrophotography sessions
- Tray holds accessories like eyepieces, filters, phones, and flashlights
Included Accessories
- Eyepieces:
- 1.25"-diameter barrel
- Accepts most 1.25" astronomical filters
- 9mm focal length produces 139x power
- 25mm focal length yields 50x power
- Diagonal:
- Eyepiece holder accepts most 1.25" eyepieces and accessories
- 90° angle places head at a comfortable viewing angle
- Star diagonal corrects image horizontally, but not vertically
- Finder:
- Unmagnified to ensure a wide field of view for finding alignment stars easily
- Reticle won't obstruct small objects
- Variable-intensity LED protects night-adjusted vision
- Software:
- NSOL Telescope Control Software: Provides basic telescope control via computer with optional RS-232 cable
