OCAL H-2 206mm f/2.72

Hyperbolic Newtonian Astrograph (H-206)

• Purpose-built for astrophotography: a fast 206 mm aperture, f/2.72 astrograph delivering ~560 mm focal length for wide-field nebulae, comets, large galaxies, and mosaics without sacrificing fine structure.

• Full-frame imaging ready: a 44 mm corrected image circle with a matched 4-element apochromatic corrector (includes one super-ED element) keeps stars tight to the corners.

• Premium optics, proven by metrology: fused-silica primary (hyperboloid) and plane secondary are verified on interferometers and eccentricity meters to ensure top-tier figure and alignment.

• Mechanical precision for repeatable results: 2.5" dual-speed focuser is thread-coupled to the corrector, integrates a dedicated bearing rotator (CAA) with angle scale, and includes a focal-plane adjustment device for easy orthogonality/tilt tuning.

• Designed to hold focus and kill flex: 4 mm carbon-fiber tube, CNC aluminum clamping hoop (10 mm thick, 22 mm wide), and carefully positioned support points deliver rock-solid rigidity for long imaging runs.

• Built-in anti-dew strategy: micro-heating dew removal plus the included OCAL anti-dew system protect critical optics through temperature swings and high humidity.

• Imaging-friendly backfocus: 55 mm from the corrector to the sensor, with M48×0.75 and M54×0.75 adapter rings for straightforward camera train integration (filter wheels, OAGs, spacers).

• Field-smart layout: 80 mm secondary sized for illumination, Noctutec German anti-reflection paint on the tube interior for superior stray-light control, and smooth, resistance-free rotation for perfect framing.

• Compact, travelable package with pro-grade protection: short overall length, robust build, and a wheeled aluminum case for dark-site convenience.

Specifications

• Model: OCAL H-2 (H-206)

• Optical Design: Hyperbolic Newtonian astrograph

• Aperture: 206mm

• Focal Ratio: f/2.72

• Focal Length: ~560 mm

• Image Circle: 44 mm full-frame

• Secondary Mirror (minor axis): 80 mm

• Primary/Secondary Substrate: Fused silica glass

• Primary/Secondary Figure: Hyperboloid / Plane

• Corrector: 4-element APO, one super-ED; clear aperture 56 mm; adapters M48×0.75 & M54×0.75; backfocus 55 mm

• Focuser: 2.5" dual-speed, threaded to corrector; bearing CAA rotator with angle scale; focal-plane adjustment device

• Tube Material: Carbon fiber, 4 mm wall

• Tube Interior: Noctutec special anti-reflection coating

• Mounting Rings: CNC aluminum, 10 mm thick, 22 mm wide, Ø 254 mm; 10× M6 threaded holes

• Dimensions: Length 630 mm; tube Ø 254 mm; max distance between dovetail plates 340 mm

• Weight (complete bare set): 12.7 kg

• Dew Control: Micro-heating dew removal design

What’s in the box?

• OCAL H-2 telescope main body (tube clamp, dovetail plate, focuser, matched corrector)

• OCAL anti-dew system

• Wheeled aluminum carry case

• Quick Start Guide

• Screwdrivers and hex wrenches for collimation/adjustment

• Data cables and DC power wires

• M48×0.75 and M54×0.75 adapter rings

Software & Docs

• Manual