SHARPSTAR 61EDPH-II APO TRIPLET F/5.5

The Sharpstar 61EDPH APO is a fast apochromatic triplet with a focal ratio of f/5.5 and a focal length of only 335mm. The objective lens includes one Extra Low Dispersion glass for a superb chromatic correction.

This telescope is light and compact and it works at its best when combined with its 0.82x field flattener and reducer (not included), resulting in the focal length of 275mm and the focal ratio f/4.4. This corrector is specifically designed for this instrument and it delivers an exceptionally large corrected image circle of 44mm where the full frame fits completely. 

The large rack and pinion 2" focuser can be rotated 360° and it has a reduction gear of 1:10 for precise focusing. The telescope has a long backfocus to allow the use of flattener/reducers and any kind of accessory. To reach the focus without the flattener/reducer, it is recommended to use a 50mm tube extension. The focuser is compatible with the ZWO EAF electronic focuser bracket.

All the lenses are fully multi-coated and the tube is internally blackened to reduce reflections and absorb stray light. The tube is made of aluminium, the rack and pinion focusing mechanism of brass and the mechanical components are engineered to provide the best rigidity, performance and durability.

Every SharpStar telescope is inspected on the optical bench by Testar and guaranteed against defects. To ensure optimal performance, the collimation of every telescope is tested using a GMK collimator. This instrument incorporates 4 LED lights that are oriented towards the objective lens and a symmetrical reflection of these lights is a synonymous of a good collimation. Here is a sample of the certificate attached to every tested Sharpstar.

GMK collimator on SharpStar 61 EDPH-II

This telescope works at its best with its own focal reducer and corrector delivering a fully corrected field of view for the full frame sensors. The CCD inspector results shows that across the entire full frame this telescope produces a "curvature" of only 23.1%. That means at the corner of a full frame sensor, stars are only 23.1% larger than in the center. For more information about CCD Inspector, please read this article in the Testar blog.

CCD Inspector results with SharpStar 61 EDPH-II combined with its field flattener and reducer. Range 2.0 - 1.0.

The field is truly fully illuminated for the entire full frame format. The maximum vignetting is only 3.5% at the corner of the sensor

• SharpStar 61EDPH f/5.6
  
• 80mm tube ring
• 100mm Vixen style dovetail bar
• Handle on the rings
• Adapter to 2" and 1.25"