The Sharpstar AL-140PH APO is an apochromatic triplet telescope with a focal ratio of f/6.5 and a focal length of 910mm. The triplet objective lens includes two ED elements for a high degree of correction of chromatic aberration.
The large 4″ brass rack-and-pinion focuser is fully rotatable by 360° to perfectly frame the subject, and it has a precise dual-speed 10:1 focusing mechanism for precise focus control. The drawtube has an opening for standard 2″ diagonals and accessories with 110mm of focuser travel.
This refractor works at its best when paired with the Sharpstar 2.5″ 0.74x field flattener/focal reducer (sold separately), especially when using full-frame cameras, to achieve a fast focal ratio of f/4.8. The use of this telescope by itself for imaging is not recommended unless you use a camera with a very small chip (diagonal size not exceeding about 10mm).
All the lens elements of this Sharpstar apo refractor are fully multi-coated, and the aluminum tube is internally blackened to reduce reflections and absorb stray light. All mechanical components including tube rings, dovetail, and carrying handle are engineered to provide the best rigidity, performance and durability.
The telescope also includes a Vixen/Synta-style finder mounting base (finder not included), tube rings, a Losmandy/D style mounting rail (180mm long), a convenient carrying handle, a metal objective dust cover, and a protective hard case. No 1.25″ eyepiece adapter is included.
- Aperture: 140mm
- Focal Length: 910mm
- Limiting Star Magnitude: 12.5
- F Ratio: f/6.5
- Resolution: 0.83 Angular Seconds
- Objective Type: Tripled Air-Spaced APO (Two Ultra-low Dispersion ED Glass)
- Total Length of Tube: 738.6m
- Net Weight: 22.3 lb (10.1kg)
- Length: 900mm (DewShield Extended), 739mm (DewShield Retracted)
- Tube Outside Diameter: 148mm
- Dewshield Outside Diameter: 179mm