Celestron Schmidt-Cassegrain telescope SC 125/1250 NexStar SLT 5 (83439)

Schmidt-Cassegrain Optics by Celestron

The Celestron Schmidt-Cassegrain telescopes combine long focal lengths with a compact optical tube assembly (OTA), making them highly portable and easy to transport. The optical design uses an aspherically figured Schmidt corrector plate to guide light to a spherical primary mirror. The light reflects back to a secondary mirror, then passes through a central hole in the primary mirror to the focuser at the base of the OTA. This closed system prevents air turbulence and protects the optics from dust.

The multi-coated Schmidt plate ensures bright, sharp images with minimal stray light reflections. With high contrast and definition, these telescopes are ideal for planetary observation. Their versatile Schmidt-Cassegrain design supports both visual observation and astrophotography, and an extensive range of optional accessories expands their capabilities. The system also works well for terrestrial observation, such as birdwatching. With an aperture ratio of f/10, astrophotography is accessible and straightforward.

Main mirror focusing provides a broad range of adjustment, accommodating virtually any standard accessory. The use of pre-loaded ball bearings minimizes "mirror shift," a common issue in simpler designs. High-quality materials like CNC-milled aluminum, cast steel, and stainless steel ensure durability with minimal weight, reducing the need for heavy mounts.

Key Features of Schmidt-Cassegrain Optics:

• Long focal length in a compact OTA
• Lightweight aluminum construction
• High-quality StarBright XLT multi-coatings
• Closed optical system to prevent dust and turbulence
• Pre-loaded ball bearings for low mirror shift during focusing

NexStar SLT Series with SkyAlign Technology

The NexStar SLT series offers computerized GoTo telescopes with a multilingual menu and access to a vast database of celestial objects. The quick-release couplings and pre-assembled tripod allow setup within minutes, no tools required. The intelligent design suggests the best objects to observe each month, making it user-friendly and ideal for beginners.

SkyAlign Technology simplifies alignment by allowing users to choose any three bright celestial objects. Enter the date, time, and location, and the telescope calculates the positions of visible objects. The Sun can also be used for alignment (with a solar filter), enabling daytime observations of planets and stars—perfect for educational use.

Standard Accessories Include:

• Computerized hand control with a database of 40,000 objects
• Detachable single-arm fork mount with quick setup features
• SkyAlign for simple alignment using any three bright celestial objects
• "The Sky" Level 1 planetarium software and NSOL telescope control software

Specifications

Optics:

• Type: Reflector
• Build: Schmidt-Cassegrain
• Aperture: 125 mm
• Focal Length: 1250 mm
• Aperture Ratio: f/10
• Resolving Capacity: 1.1 arcseconds
• Light Gathering Capacity: 320x
• Max Useful Magnification: 250x
• Tube Material: Aluminum

Mount:

• Type: Single-arm fork, azimuthal
• Motors: Servo motors with worm wheel drive
• GoTo Control: Yes, with a database of 40,000 objects
• Alignment Method: SkyAlign
• Tracking Speeds: Sidereal, solar, lunar

Tripod:

• Material: Steel
• Height Range: 76 cm to 127 cm
• Leg Diameter: 31.8 mm
• Weight: 2.3 kg

Included Accessories:

• Eyepieces: 20mm and 9mm (1.25")
• Diagonal: 1.25" 90° star diagonal
• Finder Scope: Red dot finder

Applications:

• Astrophotography: Not recommended
• Moon and Planets: Yes
• Nebulae and Galaxies: Yes
• Nature Observation and Sun: No (requires appropriate solar filter for Sun)

General Information:

• Series: NexStar SLT
• Battery Type: Mignon (AA, LR6)