Sky-Watcher Explorer 300PDS OTA 10222

“Compared to our own 250mm f/5 Newtonian reflector, the extra light gathered by the Explorer-300P was obvious. We got impressive views of a wide range of celestial objects. Galaxies such as M65 & M66 in Leo were wonderful, with strong hints of subtle detail along their spiral discs. The nearby galaxy NGC 3628 also stood out well. Nebulae shone against the background sky. M1, the Crab Nebula, showed varying degrees of mottling and scalloped edges – very satisfying indeed. The Orion Nebula, M42-43, was awash with nebulosity and we found we could easily get lost amongst the detail.. At its centre, the Trapezium group of stars sparkled and, at the highest magnifications , we spotted several of its fainter mag. +10 stars, even though the atmosphere wasn’t as steady as we would have liked for such high-magnification views.

Detail Explosion:Late into the night we selected the globular cluster M13 from the hand-controller. As it swung into the field of view it was breathtaking, with swarms of stars looking like bees around a honey pot. The view was so good that we noticed a dark feature, commonly known as the Propeller, superimposed on one side of the cluster. It was easily the best view of the cluster we’ve ever had….For crystal clear views of deep space, this is hard to beat!”
BBC Sky At Night Magazine (Review of Explorer-300P single-speed version with same mirror set)

Superb Parabolic Optics with Faster Cool-Down Time!

Supplied with a set of tube rings, 75mm Losmandy-style dovetail bar, 28mm 2” LET eyepiece, piggyback camera adaptor and a 9×50 fully multi-coated finderscope with crosshair reticle. 1.25” & 2” eyepiece adaptors are included allowing virtually any standard 1.25” or 2” eyepiece to be used. Equipped with a 2” Dual-Speed 10:1 ratio Crayford focuser which allows coarse and very precise fine adjustments to the focusing to ensure no detail is missed.

The heart of any Newtonian telescope is in the quality of its main mirror optics. The accuracy of the figure, the material they are made from and the coatings applied all play an important part. Sky-Watcher’s prowess and reputation for commercial mirror making is well known and one of the jewels in its crown. Sky-Watcher has demonstrated its unwavering ability to produce telescope mirrors of consistent high quality over decades. Parabolic (or Paraboloidal) mirrors are a complex shape so need to be well made to provide the high performance expected of them. A properly figured parabolic primary mirror will eliminate spherical aberrations by bringing the light rays to the same focal point. Sky-Watcher’s diffraction-limited parabolic primary mirrors will produce sharp, contrasty images that are full of detail.

The Explorer 300PDS primary and secondary mirrors are made from special Low-Expansion Borosilicate glass, similar to Pyrex. It has an exceptionally low coefficient of thermal expansion compared to regular glass types. In practice this means a quicker cool-down time to reach thermal equilibrium, and during the cool-down process the mirrors will maintain a better shape, reducing distortions, allowing you to start observing sooner.

The secondary mirror is held in place by four specially designed 0.5mm thin spider vane supports which are extremely rigid when tensioned. They serve to minimise obstruction to the light path, allowing the passage of more precious photons and keeping diffraction spikes to an absolute minimum.

Both primary and secondary mirrors are finished with Sky-Watcher’s RAQ™ Radiant Aluminium Quartz coatings, which include layers of aluminium, tantalum pentoxide and silicon dioxide for a brilliant, highly durable finish with 94% reflectivity that will last for years.

The colour scheme is not just an aesthetic. The OTA is tastefully finished in Sky-Watcher’s proprietary Black Diamond flecked metallic paintwork, and features, by design, complementary contrasting white painted surfaces. The white surfaces are a highly practical feature for providing more visibility, which can help prevent your expensive and carefully aligned telescope from being knocked accidentally in the dark.

With a tube weight of 23kg, this OTA would be a good match for the Sky-Watcher CQ350i Pro or EQ8-R Pro mountings