sky-watcher - Optical Vision Ltd

THE WORLD’S ONLY ASTRONOMYMAGAZINE AND CD PACKAGESKY-WATCHER PRO SERIESEquinox-80Rotatable tubeThis allows the end focuser or tubeto be rotated 360° to allow betterpositioning of objects – especially usefulfor photography. Rather than a singletightening screw, there’s a central ringto loosen the tube, which can then bere-tightened to lock it in place.ED APOPaul Money puts Sky-Watcher’s new refractorthrough its paces and reveals a package thatfuses top quality with practicalitySPECS> PRICE £425> MANUFACTURER Sky-Watcher> APERTURE 80mm (3.2-inch)> OPTICS FPL-53 Fluorite ED Glass> FOCAL LENGTH 500mm (f/6.25)> FOCUSER TYPE Dual-speed Crayford> SUPPLIER Optical Vision Ltd> TEL. 01359 244200> WWW.opticalvision.co.ukSky-Watcher’s entry into thecompetitive refractor marketlooks sleek and ready forbusiness. This 80mm (3.2-inch)ED apochromatic (APO) refractorcomes as an optical tube assembly(OTA) – that is without eyepieces– but the price does include thehandy aluminium case and a1.25–2-inch (31–50mm) eyepieceadapter. It also requires anadditional star diagonal, which isavailable to purchase separately.We mounted the OTA on anEQ6 mount to allow forphotographic testing. Our testobjects were observed using 20mm(0.8-inch) and 65mm (2.5-inch)eyepieces, a star diagonal and, on aselect few objects, a 2x Barlow.One principal test was to view abright star as it crossed the field ofview to watch for any distortionin the image. For this we chosetwo stars: Betelgeuse andProcyon. The view was pin-sharpacross 85 per cent with the 20mmlens and there was no apparentcolour fringing at all around thestars. Some slight distortionbecame apparent close to theedges, but did not detract fromthe overall view. >Tripod bushPAUL WHITFIELDThe Crayfordfocuser offersfast focusand superbfine-tuningCRAYFORD FOCUSERThe quality of the whole telescopegives the Equinox-80 a good feel, butthe Crayford focuser is especiallypractical and a delight to use. Itallows initial focus to be quicklyachieved. Then, with the dualspeedaction of the secondknob, you can fine-tune thefocus until you’re satisfied.This function really cameto the fore when we usedthe telescope for imaging.We found that wewere able to selecta bright starand carefullyfocus until it appeared pin-sharpevery time. A locking screwunderneath fixes the focus, so youcan then move back to your intendedtarget without a shift in position.The graduated scale that isnow becoming standard is alsofeatured on the Equinox, and thishelps tremendously. Once you haveachieved focus, simply note theposition on the clearly marked scaleand make a note of that position.Time and again we could come backand quickly refocus, and be eitherobserving or imaging without losingtime finding focus.The Equinox-80 features a standardtripod adapter, which means it canbe mounted on a normal tripod.The tripod bush also allows it tobe fitted to standard Sky-Watcherdovetail mounts, enabling it to beused as a photographic lens ordaylight telescope.Extendable dew shieldThis prevents dew forming on thefront objective lens – one of the mainproblems of observing or imaging. Inpractice, we didn’t lose any observingbecause the dew shield did its job well.MORE OVER PAGE

THE WORLD’S ONLY ASTRONOMYMAGAZINE AND CD PACKAGEOpticsThe objective lens ismulticoated with a fluoriteextra-low dispersion (ED) glasscomposition, giving excellentcolour correction and a sharpfield of view across 2° using a20mm eyepiece.> As the Equinox-80 has a widefield of view of around 2º, itperforms as a rich-field telescope.As such, it gave excellent views oflarge objects such as M45, thePleiades, and M31, the AndromedaGalaxy. The Perseus OB1association of open clusters thatincludes alpha (α) Persei wasstunning, with a field full of stars.PAUL WHITFIELD; PAUL MONEYDeep-sky viewsTurning towards the Orion Nebulawe had a great view of the entiresword of Orion, which consists ofthe open cluster NGC 1981 at thetop, down past M43 and M42 toiota (ι) Orionis. The Orion Nebulacould be fully appreciated, withgenerous nebulosity.Just north of it, another area ofnebulosity involving NGCs 1973,1975 and 1977 (the Running ManNebula) showed strong hints ofpatchwork. Galaxies and faintplanetary nebulae such as M81,M82 and M76 stood out and borehigher magnifications well,attesting to the quality of the optics.We wondered how, being a richfieldrefractor, the Equinox wouldperform at higher magnifications.We tackled the double stars ofCastor in Gemini, and Algenib inThe author’s superlative Pleiades shotLeo, as well as planetary detailwith Saturn and, later in the test,the Moon. Both doubles werecrisply resolved when using our2.5-inch (65mm) eyepiece coupledwith a 2x Barlow, giving amagnification of 154x. The Airydiscs merged on both doubles andthe orange yellow pair of starsforming Algenib were exquisite.We could make out goodplanetary detail with the highmagnification – Saturn displayedthe Cassini division in the rings,a belt and polar hood, and severalof its moons. The Moon seemedsmall using the 0.8-inch (20mm)eyepiece but, when we increasedthe magnification, its detail becameapparent, with excellent views.Astro adaptationUsing our own adapter we easilyattached a Canon 300D digitalSLR to the Equinox-80 and, usingan EQ6 mount to track the sky, wemanaged several imaging tests. Wetook five, two-minute, exposures ofthe Pleiades and the AndromedaGalaxy, which were then stackedand image-enhanced usingK3CCDTools.They gave a tremendous amountof detail – in fact, they were theThe main focuser is made to fit a2-inch eyepiece, but the Equinox-80 alsocomes with a 1.25-inch adapter. A brasscentral ring grips either the eyepieceor star diagonal firmly, preventingdamage to the eyepiece barrel.best images of these objects thatI have ever taken. There was someslight distortion of the stars nearthe image edges, but overall theresults were very satisfying.The Crayford dual-speedfocuser enabled fine-tuning of thetelescope’s focus, making thischore much easier. One notable,great feature is the rotatable tube,which enables better framing ofthe subjects, whether it is forvisual or photographic purposes.This did not always keep acentred star in the centre of theview, but it was certainly closeenough, and none of the testedstars were lost to view whenrotating the tube.Overall, the refractor performedwell on all the tasks. It would makea top quality, fun addition to anyastronomer’s scope collection. ✪Eyepiece adapterVERDICTOPTICS 94%BUILD QUALITY 92%ERGONOMICS 88%FEATURES 95%VALUE FOR MONEY 90%OVERALL 92%