Sky-Watcher’s 6” Traditional Dobsonian (also known as the Skyliner 150P) is quickly becoming one of the most popular and highest-recommended sub-$350 telescopes, and with good reason. The 6” Traditional offers some of the best value of any telescope in its price range, and enough accessories out of the box that you don’t have to buy anything else right away.
Overview of Sky-Watcher’s 6” Dob
- The Optical Tube
The 6” Traditional uses basically the same optical tube as the Orion XT6. It’s a 6” f/8 Newtonian – a design fairly easy to manufacture to tight tolerances. The f/8 focal ratio also makes the scope perform well even with cheap eyepieces such as the scope’s included “Supers” (which will suffer from astigmatism and other aberrations in faster scopes), and the 48” (1200mm) focal length puts the eyepiece at an ideal height for children or seated adults. The tube will fit across the back seat of most vehicles, though probably not in the trunk.
The 6” Traditional uses a single-speed 2” rack-and-pinion focuser, which largely consists of metal – unlike the 1.25” plastic rack-and-pinions found on almost all cheaper scopes. This focuser works quite well for visual use but the adapter system Sky-Watcher includes is a little confusing, requiring you to swap out 2” and 1.25” extension tube adapters depending on which size eyepiece/accessory you are using. You can get a 2” to 1.25” compression ring adapter and leave the 2” extension tube in all the time to solve this, however. The 2” eyepiece format allows you to get a wider field of view than possible with 1.25” eyepieces at low magnifications, making it easier to find targets and fit larger ones in one field. However, with the widest-field 2” eyepieces there may be some vignetting due to the rather small secondary mirror in the scope, which is inadequate to fully illuminate the field of view of all 2” eyepieces.
6 inches of aperture is the minimum size widely considered to be suitable for serious viewing of catalogs like the Messiers and Herschel 400, and can show you tons of lunar and planetary details as well as thousands upon thousands of deep-sky objects and double stars while still being relatively inexpensive and portable.
In addition to its ubiquitous 1.25” and 2” extension adapters, the 6” Traditional includes two 1.25” “Super” eyepieces which seem similar to Plossls – a 25mm (48x) and 10mm (120x). These eyepieces will serve you well to start but we’d recommend picking up a 30mm “SuperView” type eyepiece (for 40x and a super-wide field) and 6mm “goldline” (for 200x), or more expensive and fancy eyepieces if your budget suits them, to get the most out of the scope.
The included finderscope is a rather basic 6×30 unit, which works just fine, but the aperture is a little small, the images are dim as a result, and the ergonomics are less than ideal. A Rigel Quikfinder or Telrad is a good replacement or supplement to this finder, as is a 9×50 or 8×40 finderscope.
The 6” Traditional uses the same mount design as the larger Traditional Dobsonians. The altitude motion is provided by two round plastic bearings riding on Teflon cylinders attached to the interior of the mount; tensioning is provided with a spring-loaded knob (basically just a bicycle handle and a hardware store spring) on one side; the other knob serves no purpose besides aesthetics/symmetry. Overall the altitude bearing system works well – arguably better than the spring system found on the Orion Dobsonians, though inferior to the GSO/Zhumell bearing style – but the knobs stick out and have an annoying tendency to grab loose clothing or bump into you. Additionally, there is no compensation for top-heaviness when using heavy eyepieces/accessories like other commercial Dobsonians which have spring-tensioning or movable bearings; all you can do is tighten up the altitude knob or strap counterweights of some kind to the back of the tube, and either is less than ideal.
The azimuth bearing of the mount is the standard Teflon-on-laminate job, and the entire mount itself is made of particle board and assembles in minutes.
I would highly recommend the 6” Traditional to almost anyone. For beginners, 6” of aperture is enough to show you a lot and keep you happy for a long time without breaking the bank, and the 6” Traditional allows you to do serious viewing right out of the box without having to purchase a real finderscope or medium-power eyepiece like the Orion XT6. The 2” focuser also allows you to upgrade to fancy wide-field eyepieces later on. For the hobbyist who may already have a larger scope, the 6” Traditional is a great “grab n’ go” scope that can still take your expensive eyepieces and give you great views.