Sky-Watcher 10" f/4.7 Flextube 250P telescoping truss-tube Dobsonian


Availability: In stock

This 10" Sky-Watcher Dobsonian reflector is a big user-friendly telescope that is surprisingly portable. It combines the proven "more light-gathering bang for your buck" economy of the Dobsonian telescope design with the exceptional convenience and portability of Sky-Watcher's unique telescoping truss-tube system.
Our Product #: SW10D
Sky-Watcher Product #: S11720
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Product Description

This Sky-Watcher Dobsonian has:
• fully multicoated 10" f/4.7 Newtonian reflector optics
• unique telescoping truss-tube design for compact transportability
• smooth Teflon bearings, plus altitude tension control
• 10mm (120x) and 25mm (48x) 1.25" Plössl eyepieces
• 8 x 50mm right angle erect image finderscope

With the 10" Sky-Watcher telescoping truss-tube Dobsonian, you don't have to worry about lifting the scope's diagonal mirror cage and trying to bolt it to three swaying truss tubes in the dark as you do with other truss-tube Dobs. Sky-Watcher's revolutionary telescoping truss-tube system attaches the top of the truss tubes permanently to the diagonal mirror cage, with the bottom of the tubes sliding into three die-cast housings on the scope's primary mirror tub.

This unique system allows the optical tube's diagonal mirror cage and three attached truss tubes to slide down onto the primary mirror tub to form one compact assembly. The cage and tub can then be locked together, using no-tool handles built into the primary mirror tub, and lifted out of the scope's altazimuth rocker base for easy and secure telescope transport.

Assembling the Sky-Watcher Dob for use involves simply unlocking the diagonal mirror cage and raising the cage until spring-loaded catches on the truss tubes snap into place in the primary mirror tub. This holds the cage in its fully-raised position while you tighten the no-tool handles at the base of the truss tubes to lock the diagonal mirror cage securely in position for observing.

For binoviewing without unwanted extra magnification, a second set of indents on the truss tubes allows the diagonal mirror cage to be lowered to a preset locking position on the truss poles. This lets you to use a binoviewer without needing a corrector or Barlow lens in the binoviewer to reach focus.

The complete 10" Sky-Watcher optical tube assembly - secondary mirror cage, truss tubes, and primary mirror tub - weighs only 33 pounds (15 kg). The altazimuth rocker box base it sits in weighs only 27.5 pounds (12.5 kg). Total weight is only 60.5 pounds, light for a full-sized 10" telescope. When aimed at the zenith, the eyepiece is 48" above ground level.

The Sky-Watcher easily collapses in minutes into two small and light components that fit into a car trunk or into the back seat of a compact car. Competitive truss-tube Dobs break down into four or more components - secondary mirror cage, primary mirror tub, altazimuth rocker box base, and truss tubes (as many as six to be carried separately or packed into an optional carrying bag).

It's easy to see how the two-part Sky-Watcher has a definite convenience advantage over the four or more parts of a conventional truss-tube Dob. And, unlike bulky competitive solid-tube Sonotube or metal tube Dobs with an unwieldy 48" or 50" long optical tube, you don't need a big car to transport this 10" Sky-Watcher.

Assembly and disassembly take only about 5-10 minutes, with no tools needed. After you set up, particularly after traveling over bumpy roads to a dark sky site, take a few moments to check the collimation of the optics to assure peak performance and you are ready for an evening of fascinating viewing at your favorite dark sky location. The 10" Sky-Watcher telescoping truss-tube Dobsonian is designed for visual observing only - to show you as much of the night skies as possible, and do it as conveniently and inexpensively as possible. Photography is not possible with a Dob.

Because of its compact component size, light individual component weights, and limited number of components to put together (after all, there are only two!), the 10" Sky-Watcher telescoping truss-tube Dob can be transported and set up easily by one individual. This innovation gives Sky-Watcher users a cost-effective 10" telescope with unsurpassed compactness and transportability.

This Sky-Watcher Dob's Optical Tube Assembly . . .

Newtonian reflector optics: 10" diameter parabolic primary mirror, with 2.3" m.a. diagonal mirror. Both are guaranteed to be diffraction-limited. The diagonal mirror cage and primary mirror tub are made of rolled aluminum, anodized and finished externally with a subtle and attractive star-field pattern. Painted die-cast and machined rims hold the aluminum truss tubes and optical components in precise alignment to minimize the need for frequent collimation.

Primary mirror: Grade A annealed optical glass, 10" diameter, 1200mm focal length, f/4.72 focal ratio parabolic in a fully adjustable metal cell provides sharp and bright high contrast images of nebulas, galaxies, and star clusters. Lunar and planetary images are also sharp and crisp, but a neutral density (Moon) filter would certainly be called for to cut down on the incredible solar system brightness provided by this 10" mirror - over 1300 times that of the human eye. The center-spotted mirror is ground with computer-controlled accuracy, multicoated with aluminum and titanium dioxide for high reflectivity, and then overcoated with quartz for long life.

Diagonal mirror: Grade A annealed optical glass 2.24" m.a. diagonal mirror, mounted in a fully adjustable diagonal holder on a low-diffraction four-vane thin spring steel spider. The diagonal mirror is polished flat to diffraction-limited accuracy. As with the primary mirror, the diagonal is multicoated with aluminum and titanium dioxide for high reflectivity and overcoated with quartz for long life.

Finderscope: 8 x 50mm right-angle erect image achromatic crosshair design. The images in the finder are erect and right-reading, with star patterns looking just as you see them on star charts or with your bare eye. It is mounted near the focuser, with the finder eyepiece vertically aligned in the same direction as the telescope eyepiece. This eliminates the constant head twisting involved when switching between the horizontal orientation of a conventional Dob's straight-through or red-dot finder and the vertical orientation of its focuser and eyepiece.

Focuser: machined aluminum 2" Crayford focuser with a 1.25" eyepiece adapter.

Eyepieces: 10mm and 25mm 1.25" four-element Plössl eyepieces with a 52° apparent field. The 25mm provides a magnification of 48x with an actual field of view that is 1.08° across. That's more than twice as wide as the full Moon. The 25mm gives rich and expansive deep space views of star clouds, galaxies, and nebulas alike. The 10mm Plössl provides a stout 120x magnification with a 0.43° field of view, enough magnification to provide sharp close-up views of the Moon, planets, globular star clusters, and more.

Optical tube dimensions: Tube diameter (outside of one side bearing to the outside of the other bearing): 13.5"; tube length collapsed: 31.5"; tube length extended: 44".
This Sky-Watcher Dob's Base Assembly . . .

Rocker box altazimuth base: The altazimuth rocker box that the mirror tub rides in is crafted of strong, lightweight, and water-resistant laminated particle board, as is the water-resistant ground board that the rocker box rides on. The base is shipped disassembled, but can be put together in about a half an hour using only a screwdriver and the supplied hardware. Teflon bearings in both altitude and azimuth provide smooth and effortless motion of the optical tube in all directions. At the same time, the Teflon provides the proper amount of stiction to assure backlash-free movement, without the inadvertent and uncontrolled motions sometimes caused by wind gusts pushing on mounts using azimuth roller-bearings.

Navigation knob: A navigation knob conveniently mounted below the focuser makes it easy to control the scope' motion in any direction. The optical tube starts moving at a gentle touch - smoothly and with no fuss. Center on an object and the scope settles down immediately, with no shudder or vibration to mar your viewing experience.

Carry handles/altitude tension control/eyepiece tray: The handles in the sides of the rocker box incorporate a tension control in altitude that lets you compensate for eyepieces of markedly differing weights. An eyepiece tray capable of holding one 2" and three 1.25" eyepieces attaches to the front of the rocker box above the supplied centrally-mounted carrying handle.

Altazimuth base dimensions: 20" in diameter by 29" high.

What can you see through the 10" Sky-Watcher telescoping truss-tube Dob?

In viewing deep-space, aperture matters - big time! With the 10" Sky-Watcher, you have tremendous light gathering power to see faint and distant nebulas and galaxies - over 1300 times that of your unaided eye. Under dark skies, the Orion Nebula becomes a glowing and subtle complex of filaments, and color starts to become visible. The spiral structure of the Whirlpool Galaxy becomes apparent, as do dark dust lanes across the nucleus of the Andromeda Galaxy (although the full 3° width of the galaxy itself is far too large to fit into the field of view of any eyepiece generally usable with the scope). Globular clusters are frequently resolved to the very core. Messier, NGC, and IC objects show detail and structure never visible in smaller telescopes.

Many challenging objects for an 8" aperture scope now come into their own with the 10" Sky-Watcher. The Crab planetary nebula (M1), a supernova remnant, requires a 10" aperture to truly begin to appreciate its subtle, gaseous filamentary structures. M33, the low surface brightness face-on spiral galaxy in the constellation Triangulum, exhibits significantly more open arm structure than is visible in an 8" scope. The Rosette Nebula in Monoceros begins to show the pattern of a blooming rose that gives the Rosette its name.

There is no question that the increased resolving power and 56% greater light-gathering power of a 10" aperture is visually impressive when compared to an 8" scope. Therefore, it is no wonder then that the 10" aperture is overtaking the 8" as the serious amateur astronomer's aperture of choice in a Dobsonian telescope. Sky-Watcher's compact, telescoping optical tube design makes the decision to step up in aperture to a 10" scope even easier.

As with any large aperture telescope, the performance of the 10" Sky-Watcher on faint objects will be markedly improved by a dark sky observing site. Light-polluted city and suburban sites are not recommended as the primary observing site with a 10" scope. Such sites require a nebula (light pollution) filter to take even limited advantage of its immense light-gathering.

While it is in deep space observing of galaxies and nebulas from a dark sky observing site that the 10" Sky-Watcher telescoping truss-tube Dob excels, significant planetary and lunar observing is also within its capability. All you need is a neutral density eyepiece filter to cut down the immense brightness of solar system objects seen through this "light bucket."

Taking advantage of the weight-saving sophistication of its telescoping truss-tube design, the 60.5 pound Sky-Watcher 10" Dobsonian makes it practical for one individual on his or her own to explore the heavens with a truly big scope, whether from a back yard or a distant dark sky observing site. This Sky-Watcher 10" telescoping truss-tube Dobsonian reflector will keep you happily observing for many years to come.

Tech Details

Aperture 10"
Focal Length 1200mm
Focal Ratio f/4.7
Heaviest Single Component 33 lbs.
Highest Useful Magnification 300x
Weight 60.5 lbs.
Optical Coatings 94% Aluminum
Resolution 0.46 arc seconds
Supplied Eyepiece 25mm and 10mm 1.25″ Super Plossls
Telescope Type Reflector
View Finder 8×50 Right Angle Correct Image
Visual Limiting Magnitude 14.5
Warranty 1 year


Review by:
This is my first Dobsonian and I love the simplicity of the design. The optics are outstanding and provide very pleasing views. There was a bit of a learning curve for me on proper collimation, but that became an easy and even enjoyable part of the set up. Binary stars have become one of my favorite objects as they are easy to find and are presented as beautiful pinpoints with true color. The large aperture is great on DSOs and for planet detail and contrast. Though this is a large telescope, the collapsible design makes it easier to move and store. It fits nicely in the back seat of our compact car with no problem. I use a two-wheel dolly to move it fully assembled in and out of the house. Though there is some extra effort in the set up, the outstanding views are well worth it. Aperture does indeed rule! (Posted on 7/28/2019)
Review by:
I've only had my Sky Watcher for a few months but have had a great time learning my way around the universe. It 's easy to store and transport a d quick to set up when you get there. Extend the tube, check your collimation , put in an eyepiece s and your ready to go! (Posted on 1/6/2019)
Review by:
This was the first telescope that I got when it was a kid at about the age of seventeen. I would say if you live in a high LP area, as for me in the suburbs of the city of Chicago, to go with the bigger aperture dobs if you have the funds for it. If not, this is still a spectacular telescope for beginners and up. The collimation process is very simple and will help tremendously if you get a "red laser" as I like to call it such as the Orion brand in which I use called the "Orion LaserMate Deluxe II Telescope Laser Collimator". Using this scope in high Light Pollution zones, I would also recommend the filter "Orion UltraBlock Narrowband Filters" before using this in the suburbs of Chicago I wasn't able to see any Nebulas besides the Orion Nebula. After using this filter so many nebulas such as the swam, lagoon, eagle, veil, and more popped out in the eyepiece when I was properly dark adapted. So, In the end, I would recommend this telescope to anyone looking into VISUAL astronomy only. (Posted on 12/20/2018)
Review by:
I've had this scope for 13 months and chose it because it's collapsible nature enables it to fit in my ultracompact car (which a solid tube would not), and also use up less space when stored at home. The main caveat is the fact that extending the trusses every use means having to collimate it every night. I did not foresee the impact that would have on the "grab and go -ability" of this scope.

I live under very light polluted city skies (Bortle 8), and I've found that while 10" of aperture is great, from the city most deep space objects are out of reach visually because of the light pollution (and more aperture won't help), and that has pushed me towards observing DSOs mostly using a smaller telescope on a motorized mount, with an astronomy camera (video astronomy). I wish I had gotten the goto version of this Skywatcher dobsonian, because that way I'd be able to use it for imaging / video astronomy instead of having to use the smaller scope. The collapsible SW dobs has plenty of in-focus so it's very camera friendly.

So my conclusion is: if you live in a city, you either need access to a dark site (with collapsibility making the trip easier) or you should consider getting the goto version, to be able to use astronomy cameras for better DSOs observing from the city. (Posted on 11/15/2018)
Review by:
I have had this telescope for more than 4 years and what I enjoy the most is its easy transportation and how easy it is to store, it occupies little space so it is very portable. for observation is very comfortable is perfet for one seated in a conventional chair. Collimation is very simple and it is advisable to use a laser to perform it. Excellent equipment for lunar observation and deep space. (Posted on 10/29/2018)
Review by:
I received one of these in August, I immediately noticed just how nice it was. As in the previous review, I to had to add magnetic counterweights to the back, I installed the Bobs knobs. The springs in the primary should be replaced with stiffer ones to help hold collimation from session to session. It put up spectacular views, especially Orion. A coma corrector should be considered, but I have felt no need for one as of yet. Wish I would've gotten a twelve. The weight isn't that bad at all for me to lift and carry this in one piece (Posted on 10/6/2018)
Review by:
I am mostly an astrophotographer, but I wanted to participate in my astronomy club's outreach events, and this scope has been great for that! I did get an astrozap shroud, but even without it, this scope is great for quickly finding planets, which is what most people want to see at outreach events. I use the RACI finder it came with to center the object back in the eyepiece for people, and that is fast and works great! I also appreciate that I can collapse it to fit in the back seat of my sedan upright! I buckle it in. My only complaints: 1. I needed to add weights to the back for it to balance with even a moderate eyepiece. 2. I think it is a bit over-priced compared to some of the competition at full price. Get around this by waiting for a sale! (Posted on 10/6/2018)
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Supplied Accessories

  • Telescoping no-tool assembly truss tube design
  • Rolled aluminum /die-cast secondary mirror cage and primary mirror tub
  • Navigation knob
  • Laminated altazimuth mount with Teflon bearing surfaces and altitude tension control
  • 4-vane spring steel diagonal mirror support with adjustable mirror holder
  • Adjustable primary mirror flotation system
  • Diffraction-limited Grade A optical glass mirrors
  • Protective primary mirror cover
  • 2" Crayford-style machined aluminum focuser with 1.25" eyepiece adapter
  • 25mm (48x) and 10mm (120x) 1.25" Plössl eyepieces
  • 8x50mm right angle finderscope.