In its 10-inch Premium Dobsonian, Revelation has taken a classic design – a rolled steel tube, a simple Dobsonian mount and a large parabolic mirror – and finessed it to produce a satisfying product. Completing the system are a 1.25-inch 9mm Plössl eyepiece, a 2-inch 30mm Superview eyepiece, an 8x50 finderscope and an eyepiece rack, all at an affordable price.
Assembling the base unit is relatively straightforward, especially if you have any experience with flat-pack furniture. Clear instructions and a small Allen key are provided, but you will also need a crosshead screwdriver. The bearings and bolt, which provide smooth azimuth movements, were easier to position than many other mounts we have assembled in the past. The clutch bearings for the tube are packaged separately, but once attached they can be left in place if you chose to put the scope back into its box for transport.
We found these bearings to be essential when lifting the scope, as there is very little else to grasp when doing so – the provision of a handle is one small detail we felt had been overlooked. It is quite easy to move the bearings into the cradle though, even in the dark, and all bearing adjustments were easy to carry out. The eyepiece rack was a useful addition and we also found it was quite convenient to store the dust covers inside the base of the mount, meaning it wasn’t necessary to take a box or table out to our observing site.
Nice and easy does it
The beauty of this type of mount lies in the speed of setup and simplicity of use compared with more complicated designs. The tube isn’t light or particularly easy to manhandle due to its slippery round surface, but during our testing period we were glad to be able to take our chances to pop out for some brief observing between the clouds. The large mirror in its closed tube does need time to cool down, but a battery-operated fan is built into the cell to speed up the process. For part of our testing period, we took the telescope to Snowdonia and were able to keep it in a dry but unheated store, which meant the cooling period was shorter.
A 10-inch telescope gathers 56 per cent more light than an 8-inch instrument, making visual observations of relatively faint deep-sky targets a breeze. We also made good use of the long focal length (f/5) to zoom in on some planetary and lunar targets, with great results. We were impressed with the sharp views this scope produced: the mirror arrived well collimated and the field seemed very flat.
With the 30mm eyepiece we enjoyed beautiful star clusters such as the Beehive in Cancer. With so many more visible stars than are possible in a small refractor, this certainly produced the elusive ‘wow factor’. When the Moon was out of the way, we turned to the Leo Triplet, where we could easily discern the different shapes of M65 and M66. Higher in the sky, M51 was easy to find through the finderscope, and in the main scope we could see hints of the structure as well as NGC 5194, the dwarf galaxy with which it interacts.
Moving on to the planets, and with the higher-powered 9mm eyepiece we saw good colour variation on Jupiter and some detail within the belts, as well as the four Galilean moons. Mars was very rewarding: although not quite at opposition, it was still easy to define the larger surface features and polar cap, and our observations compared favourably with simulations from planetarium software. Lunar views were good too, with excellent contrast across the surface as well as around the terminator, although a filter is useful for coping with the dazzling brightness around full Moon.
Being a manual Dobsonian without tracking facilities means that keeping your target on view in the eyepiece at high magnification requires some skill. Nonetheless, this 10-inch instrument is delightfully simple to use, and provides a serious amount of aperture and high quality observing for beginners and advanced astronomers alike.
Architect Ludwig Mies van der Rohe once said of design: “God is in the details.” In this case, the outstanding element of this scope is its complete set of well-engineered details. Revelation has provided good optics, and has not cut any corners on the quality of the parts that are essential for a satisfactory night’s observing. The bearings, clutches, focuser, fan and finder all work effectively – and not just indoors, but when you are fully wrapped up and in a dark field in north Wales! The focuser can easily handle a heavy eyepiece and even a camera, although the astrophotography opportunities for a hand-guided mount are limited. The balance of the tube can even be adjusted by tightening the bearings to facilitate the addition of heavier accessories.
The recognisable planets and thought-provoking galaxies provided by this scope’s big aperture make great eye-openers for beginners, but this is a high-quality optical instrument that will also satisfy the dedicated amateur.
Clutch controls - The altitude bearings on this scope are very effective. The glove-friendly, CNC-machined metal wheels control the ease of movement beautifully. The bearing cases also locate very positively in the cradle, facilitating easy assembly even in the dark.
Smooth focusing - The very chunky, well-engineered, 10:1 dual-speed Crayford-style focuser is provided with an adaptor that allows you to use either 2-inch or 1.25-inch eyepieces and accessories. Thumbscrews provide friction adjustment, while the locking facility makes it a pleasure to use, with smooth, fine movements and no backlash.
Cooling fan - The mirror cell has a built-in fan to assist cooling and help to shift warm layers of air from the main tube. The battery holder takes eight AA batteries; you could alternatively use a 12V powertank supply if you think you will be using the fan a lot.
Finderscope - The finder has 8x50 optics and a traditional crosshair reticule, offering a view the same way up as the main scope and revealing plenty of faint stars to hop between. Its mount is sturdy and very simple to adjust, and it stayed well aligned throughout the test period.
Sturdy base - The rigid base rotates via a large roller bearing, which turns very freely. A large plastic knob can be tightened to provide the perfect amount of friction: just loose enough to push the scope into position, but tight enough to stay put when lightly touched or in a stiff breeze.