Sky-Watcher Esprit 70EDX Super APO Triplet f/6.5 Telescope

Sky-Watcher Esprit 70EDX: A 70mm f/6.5 APO for Imaging and Visual Use

Sky-Watcher designs the Esprit EDX series primarily for astro-imagers, and says they are also fine telescopes for visual observation. The 70EDX has a 70mm aperture and a 455mm focal length at f/6.5.

Optical Design: 3-Element Objective with Hoya FCD100 Glass

The objective is a three-element, air-spaced lens with one Hoya FCD100 ED element. The Esprit 70 manual describes no visual color fringing even on bright objects.

The lenses carry Sky-Watcher's proprietary Metallic High-Transmission Coatings (MHTC). The optical system is knife-edge baffled.

455mm Focal Length at f/6.5

The Esprit 70EDX's optical parameters, a 70mm aperture and 455mm focal length, result in a native f/6.5 focal ratio. The 455 mm focal length suits wide-field imaging.

Visual Observing with the Esprit 70EDX

Sky-Watcher supplies the 70EDX without eyepiece, star diagonal and finderscope. The drawtube adaptor accepts a 2-inch star diagonal, and the finderscope shoe takes Sky-Watcher finderscopes.

Astrophotography with the Optional Esprit 70 Flattener

A dedicated thread-on Esprit 70 field flattener, with two lenses, is sold separately for imaging. It is not needed for visual use.

Before installing the flattener on the drawtube, unscrew and remove the 2-inch ring adaptor. The manual then shows the extender tube and an enlarged 48mm T-ring for your camera. Without the flattener, the extension adaptor connects the camera.

The 2.7-inch Focuser with 11:1 Dual-Speed Control

The Esprit 70EDX is equipped with a CNC-machined 2.7-inch rack and pinion linear power focuser. It offers a high accessory load capacity and zero image shift. Focus with the knobs until the image is nearly sharp, then use the 1:11 knob for fine focus.

The indexed scale on the drawtube shows the focus position for each accessory; fine tuning is still advised. skywatcher.com says the 70EDX does not have a rotatable main focuser, but a rotatable adaptor on the drawtube helps frame images: unscrew the blocking ring at the end of the drawtube, turn the adapter ring with the optical train, then screw the ring back to lock it. Lock the lever below the focuser if a heavy load is attached.

Mechanical Build: A 3.2 kg OTA Measuring 368mm

The aluminum optical tube weighs 3.2 kg (7.1 lb) and measures 368 mm with the dew shield retracted, 420 mm extended (skywatcher.com). The dew shield is retractable.

The telescope comes with a set of CNC-machined aluminum tube rings, a carrying handle, and a 45 mm Vixen-style dovetail bar for mounting. A Sky-Watcher finderscope mounting shoe is fitted; the manual notes the finder can be removed during an observation if it gets in the way.

Threads and Adapters for Your Imaging Train

The focuser drawtube terminates in a male M74 x 1 thread. The manual's thread diagram also shows M65x1, M62x1 and M48x0.75 threads in the imaging train with the optional flattener. A Canon EOS camera adapter is included.

Choosing a Mount for the 7.1 lb Optical Tube

The optical tube weighs 3.2 kg (7.1 lb) and comes with a 45 mm Vixen-style dovetail bar, so it needs a mount with a Vixen-style saddle and a payload rating that covers the tube plus your camera and accessories.

Transport and Care with the Included Aluminum Case

The Esprit 70EDX comes in a sturdy foam-lined aluminum case, designed to carry the telescope and the tube rings securely.

Getting Started: From Case to First Light

The image usually needs fine refocusing over time as the temperature changes, which often happens when the telescope has not yet reached the outside temperature. For visual use, insert a 2-inch diagonal in the drawtube adaptor, then an eyepiece.

If you are imaging, attach your camera via the appropriate adapters. Make sure the focuser's locking lever is unlocked, focus with the knobs, then fine focus with the 1:11 knob. Never look at the Sun directly through the telescope: permanent eye damage will result. Use a proper solar filter firmly mounted on the front, never an eyepiece-type solar filter, and never project sunlight with the telescope.