august 09 first light: an in-depth look at this month's hottest new product

sky-watcher Skyliner-300P FlexTube Auto Sky-Watcher’s latest Dobsonian telescope can track the stars so that the views through its huge aperture stay in the eyepiece. Paul Money takes a look

Vital stats hen John Dobson MDF rocker base here, like the plug it into a power pack, neither created the telescope setup of some other Dobsonians. of which are supplied. > Price £1,099 design that bears his This is no doubt to ensure that the The Skyliner’s 1,500mm of > A perture 305mm (12 inches) name, he would scarcely have 300P’s axis motors stay accurately focal length collapses down to > Focal length 1,500mm; f/5 imagined how it would evolve installed. Instead, you just lift the just under a metre thanks to its > Op tical design Newtonian thanks to Sky-Watcher. First, tube assembly onto the rocker telescopically extending trusses, reflector > Finder 9x50 straight-through the company came up with the base and the main job’s done. All making it extremely portable for > Eyepieces 25mm, 10mm; FlexTube collapsible truss tube, that’s left is the 9x50 straight- such a large instrument. We were 1.25-inch fit which greatly improved through finderscope to assemble impressed to find no collimation > focuser Crayford; 1.25- & 2-inch fit portability. Now it has added and the hand controller to install. issues, even after repeated setups. > mount Motorised Dobsonian auto-tracking motors to the The 300P comes with two And with its tracking motors, we > Weight 40kg FlexTube design, taking the eyepieces, a 25mm and 10mm could take decent images of the > Supplier Optical Vision Dobsonian on its next great 1.25-inch fit that give 60x and Moon and planets, despite the > www.opticalvision.co.uk leap forward. 150x magnification respectively. fact that long-exposure imaging > Tel 01359 244200 The Skyliner-300P FlexTube Its Crayford focuser can also take has never been the domain of Auto is a delight to use, especially 2-inch eyepieces with the supplied the Dobsonian in the past. as it comes almost fully adaptor. To power the system assembled; there’s no hassle of there’s a battery holder that takes Time to cool off having to assemble a flat-packed eight size D batteries, or you can Like all large telescopes, we found that it was best to set up the 300P at least half an hour before use. auto tracking to the rescue This was so that the tube could cool down to the ambient Dobsonian telescopes are great With the 25mm eyepiece, our temperature and stop the eddying light-gathering instruments, but their targets stayed in the central 50 per drawback has always been the need cent of the view for more than 30 air currents in the tube disturbing to move the mount manually to keep minutes, with only a small amount the view and affecting objects in view. Not any more. The of drift – plenty of time to enjoy even performance. The open truss FlexTube Auto’s tracking motors are the most engrossing views. Power design at the front of the tube a fantastic addition. The days of comes from eight D-type batteries or assembly helped speed up the pushing a Dobsonian around the sky by plugging in a power supply. We are numbered. had no problems using batteries, cooling process. In use, the The auto tracking was easy to set which lasted for several nights. Skyliner turned out to be quite up: you only have to put in your The Skyliner 300P’s auto tracking smooth to move around manually, latitude. Then, you can manually feature is an accomplished addition considering that it has motors on move the scope to your target, or to John Dobson’s great design. How slew to it with the motors. And by long will it be before we see the next both axes. There was a bit of play, pressing two buttons on the hand step in the Dobsonian’s evolution, but it wasn’t a major problem. controller, you select tracking mode. with the addition of Go-To? Checking the optics with the

all photos: whitfield paul supplied 25mm eyepiece, we >

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Focuser

Getting a perfect focus is essential for visual and imaging use. We were able to catch subtle details in deep-sky objects with fine adjustments made to the Crayford-style focuser. It wasn’t too stiff and it didn’t have too much slack.

Optics

A 12-inch mirror collects 44 per cent more light than a 10-inch, but if the optical surfaces are poorly figured or out of alignment then that extra light could be wasted. Fortunately, there were no apparent defects in any of the mirrors.

Motor drives and controller

The motor drives were smooth to operate and kept celestial objects in view for at least 30 minutes, with a little drift over longer periods. At high powers we noticed a slight jerkiness to the views as the motors adjusted the position in both axes. The hand controller is simple to use.

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august 09 first light: an in-depth look at this month's hottest new product

> got a crisp view of the star Vega across 65 per cent of the field of Finderscope Mount view before it trailed off towards The finderscope gives a bright, wide The mount was able to the edge. When we swapped in field of view for initially locating handle the 300P tube our own 25mm Plössl eyepiece objects. It is positioned close to the assembly with ease and of known quality, we got a better focuser but doesn’t impede it, and it’s was very easy to set up result: sharp views across 75 per easy to look through without having despite its bulk. Motion in cent of the field. The Moon fitted to crane your neck. both axes was smooth and the height of the rocker in the 25mm eyepiece’s view box put the eyepiece-end with room to spare and revealed of the tube at a reasonable impressive detail and sharp height for viewing. relief in the craters of the lunar southern hemisphere. Saturn was also a beguiling sight, revealing two belts, a very thin ring system and, on one night, seven of its moons.

Deep-sky greats When we turned to the Double Double, the star Epsilon Lyrae, the 10mm eyepiece revealed a very refined view indeed, clearly splitting the famed star into its four components. With the resolution test criteria truly met, and with sky conditions on the night seemingly exceptional, we pushed the envelope by dropping our own 5x Powermate Barlow into the optical train with the 10mm eyepiece. Loaded with magnification equivalent to a 2mm eyepiece, we sought out Zeta Boötes – a double star with just 0.7 arcseconds of separation. Overall, the Skyliner put in a We could make out the two stars premier performance, but the with their Airy discs (ring patterns real delight is its tracking, which surrounding them) overlapping keeps objects in view for pretty during moments of steady seeing long periods of time (see ‘Auto – astounding! tracking to the rescue’ on page The deep sky was equally 90). This gives you all the striking. The whirl of spiral arms pleasures of viewing the night sky around M51 and the dust patches with a large telescope without the along the disc of galaxy M82 drawbacks of setting up a large were two particularly memorable and heavy equatorial mount. sights. Messier 13, the Great Thoroughly recommended. ✪ Globular Cluster in Hercules, was stunning with the 10mm eyepiece, with innumerable stars Verdict surrounding its densely packed Build quality 94% core. Nebulae really benefitted Ease of Use 92% from the Skyliner’s light grasp: Features 95% M17, the Omega Nebula in optics 92% Sagittarius, and M27, the Dumbbell Nebula in Vulpecula tracking accuracy 90% Overall all photos: whitfield paul showed some lovely detail. 93%

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