Cassegrain Telescope 203mm F/12 OTA

Cassegrain telescope 203mm f/12 OTA for astrophotography and visual observation is designed for pure precision. With 203mm aperture, an impressive focal length of 2436mm and a classic Cassegrain configuration, this telescope offers exceptional sharpness and contrast, perfect for high-res photography of planets, the moon and double stars.

The f/12 ratio and closed design make this instrument particularly suitable for observation sites with moderate seeing or high humidity. The tube maintains collimation well and requires minimal maintenance, with a more compact form than a comparable refractor of the same focal length.

✓ 203mm aperture – high light gathering for detailed observations
✓ f/12 focal ratio – ideal for planets, double stars and lucky imaging
✓ Closed design – less sensitive to dust and temperature fluctuations
✓ Compact tube form – easier to mount than long refractors
✓ Exceptionally suitable for photography with barlow and planetary cameras

With this telescope, you can easily capture Saturn’s Cassini Division, detail in Jupiter’s cloud bands, or a moon’s shadow during a transit. Visually, it’s also a powerful instrument for double star enthusiasts and for high-magnification lunar detail.

Application

• Photography of planets, the moon and double stars
• Visual observation with high magnification
• Compact alternative to a long refractor (e.g., 150mm f/15)
• Suitable for permanent setup, balcony observation or observatory use

What You Can See

✓ Mars details during opposition, Saturn’s rings and moons
✓ Jupiter transits and Great Red Spot
✓ Superb separation of double stars down to 0.5″ separation
✓ Crater structures and rilles on the moon at 300x magnification
✓ Visual observation without chromatic aberration

Filters / Features

• Telescope type: Reflector
• Design: Classic Cassegrain
• Lens diameter: 203mm
• Focal length: 2436mm
• Aperture ratio: f/12
• Focuser: 2″ connection (usually via adapter)
• Usage type: Planetary photography / double stars / moon
• Mount connection: Vixen or Losmandy-style dovetail (depending on version)
• Suitable for beginners: ✗
• Suitable for advanced users: ✓
• Suitable for observatories: ✓

Technical Specifications

• Optics: Classic Cassegrain with 2 mirrors
• Primary mirror: Parabolic
• Secondary mirror: Hyperbolic
• Coating: Alu + SiO₂ reflection coating
• Aperture: 203mm
• Focal length: 2436mm
• Tube length: approx. 600-650mm
• Weight: ± 7-8 kg
• Construction: closed tube
• Focuser: usually via rear connection with optional Crayford
• Included: OTA, dust cap, dovetail
• Mount: not included