FIRST LIGHT
Sky-Watcher Evolux 82ED refractor
A dinky, smart, grab-and-go scope that still delivers big on performance
VITAL STATS
• Price £649
• Optics air-spaced doublet refractor with ED lens
• Aperture 82mm
• Focal length 530mm, f/6.45
• Focuser CNC-machined dual-speed rack and pinion
• Extras tube ring, Vixenstyle dovetail bar, 2x finderscope brackets, carry case, 2-inch eyepiece adaptor
• Weight 2.9kg • Supplier Optical Vision Ltd
• Email info@opticalvision.co.uk
• www.opticalvision.co.uk
As the name suggests, the Sky-Watcher Evolux 82ED is an 82mm-aperture refractor that builds on the legacy left by Sky-Watcher’s Evostar range, popular with beginner and intermediate astronomers. However, at 2.9kg and a mere 425mm long when the dew shield is retracted, the Evolux is designed as a more compact and lightweight addition to Sky-Watcher’s lineup.
The Evolux 82ED arrived in a single box, revealing a solid and well-padded aluminium carry case. We were surprised at how compact this was for an OTA (optical tube assembly) of this aperture and focal length. We immediately appreciated the lightweight build and noted the extra-long dew shield, which gives extra protection from the elements when fully extended. A single clamshell-style tube ring with a pair of finder/guidescope brackets connects firmly to the short Vixen-style dovetail bar. At the back, Sky-Watcher has dropped the Crayford-style focusers seen on other models for a more robust 2.4-inch rack and pinion focuser.
This utilises a linear geared bar on the underside of the focus barrel, which promises to hold a greater weight with less risk of slippage than legacy Crayford focusers which rely on friction alone to maintain position.
All features great and small
The Evolux’s weight and dimensions render it a perfectly portable grab-and-go telescope, suitable for both astronomy and astrophotography. Cosmetically, the refractor is finished in the traditional white and green associated with modern Sky-Watcher products, which makes for an attractive setup. However, the impressive lightweight spec appears to have been achieved by using thinner materials. Although well put together, the OTA’s construction feels perhaps less robust than older models. The dew shield also feels very thin, and while retracting and extending it we noticed a slight judder and some friction sounds, implying it may be susceptible to knocks and marking over time. One thing that isn’t flimsy is the machined tube ring, which holds the refractor snugly and securely.
Bright, wide views
The Evolux 82ED is an air-spaced doublet apochromatic refractor that uses extra-low dispersion (ED) glass for one element, with a matching crown element. ED glass has been specifically formulated to reduce chromatic aberration when used in a twin-lens (doublet) configuration. The ED glass helps focus all three colour channels (red, green and blue), reducing the coloured halos often seen in single or doublelens refractors. The ED glass element also improves light transmission and, combined with Sky-Watcher’s Metallic High-Transmission Coatings (MHTC), claims to offer 99.5 per cent light transmission.
At 530mm focal length (f/6.45) native or 477mm (f/5.8) with optional focal reducer, the ED82 offers a good range of focal lengths. The longer end, when paired with smallerchip cameras, will work well for galaxies, smaller nebulae and globular clusters. Adding the optional focal reducer brings larger nebulae and galaxies into play, like Andromeda and Orion. With this range of options, you will not be short of targets in any season
Once attached to our mount, we found that the short Vixen-style foot allowed perfect and quick balance with an eyepiece fitted. On attaching a heavier DSLR camera, we couldn’t move the scope forward enough to obtain balance. Sky-Watcher has designed for this, however, and we were able to remove and reposition the dovetail bar on our mount, allowing the Evolux to be mounted further forwards to achieve perfect balance.
Slewing over to our first target, we were pleased to find that focus could be easily achieved without the need for additional spacers – always a bonus. The dual-speed rack and pinion focuser was smooth but felt a little spongy, so fine adjustments were perhaps clumsy, but it held perfect focus all night.
Mini marvel
Running our first 30-second exposure revealed a very flat image that had round stars across the majority of the field, with mild vignette and stretched stars around the edge and in the corners. However, for this test we were using a full-frame camera, which can be challenging for high-end refractors. We then attached the optional matching field flattener/reducer, which was easy as it screwed directly onto the focuser barrel while our DSLR connected to the reducer. This gave a very solid connection, with no risk of slippage or of the camera falling. Once focused, we were pleased to see that with the wider field of view the stars were still mostly round, with only a slight vignette and curvature towards the corners.
We set our camera running for a night of imaging and then processed the images the following morning. Applying an initial stretch revealed some colour fringing and bloating around the brighter stars, but nothing that we couldn’t correct and control. The stacked images revealed very crisp nebulae and a surprising amount of fainter detail for only an hour of exposure time per target. With calibration frames applied, vignetting was still evident in the corners, but the central area was beautifully uniform.
The Sky-Watcher Evolux ED82 as an entry-level refractor didn’t disappoint, and provides everything budding astrophotographers and visual astronomers could ask for. It’s a petite deep-sky refractor looking to deliver big performance.
KIT TO ADD
1. 0.9x ED focal reducer/ flattener
2. M48 x 0.75 adaptor for Nikon or Canon cameras
3. Aluminium accessory handle
