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Sky-Watcher Flextube 250P f/4.7 Dobsonian Telescope

SKU : SW-S11720

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  • Aperture: 254mm (10")
  • Focal Ratio: f/4.7
  • Focal Length: 1193mm
  • Optical Design: Open Tube Newtonian
  • Tube Weight with Accessories: 33 lb
  • Overall Weight: 59.5 lb
  • Will ship directly from Sky-Watcher in the continental US

Product Details

  • The Sky Watcher 10" Dobsonian is an instrument that will provide a lifetime of continued exploration of the cosmos. This telescope will hit the sweet-spot for many amateurs, providing all the capability and value you are seeking in a large aperture telescope. Sky-Watcher's revolutionary truss-support concept allows the optical tube's front and back cells to collapse together, aligning on the truss support rods which can then be locked down for easy and secure telescope transport. This one piece, low-hassle OTA design is mechanically simple and results in a large aperture telescope that can be reasonably handled and transported by one individual. This innovation gives Sky-Watcher users tremendous functional ease-of-transportability.

    In viewing deep-space, aperture matters - big time! With this telescope you have tremendous light gathering power. Prominent deep-space objects seen well in the 10" Sky-Watcher Dobsonian, such as diffuse emission nebulae in the summer sky like the Lagoon (M8), Trifid (M20), and Swan (M17); the stunning globular star clusters M13 and M92 in Constellation Hercules; the awesome winter sky's Great Orion Nebula (M42) in Constellation Orion, and our enormous local galaxy group companion the Andromeda Galaxy (M31) in Constellation Andromeda, to name a very few, will appear more spectacular, brilliant, and wider in extension in a Sky-Watcher 10" DOB.

    Many challenging objects for an 8" aperture now come into their own with the SW 10" DOB: the planetary nebula the Crab (M1), a supernova remnant, requires a 10" aperture to truly begin to appreciate the several subtle, gaseous filamentary structures. M33 the spiral galaxy in Constellation Triangulum exhibits significantly more open arm structure. The Rosette Nebula in Monoceros begins to show the discernable pattern of a blooming rose. M51, the fascinating spiral Whirlpool Galaxy, displays remarkable greater structural detail in a 10" aperture vs. 8" diameter size telescope.

    There is no question the incremental resolving power of a 10-inch aperture is visually impressive when compared to an 8-inch. 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, collapsible optical tube design makes the decision to step up in aperture to a 10" even easier.

    Sky-Watcher Dobsonians Epitomize Ease-of-Use

    Observing with a Dobsonian has been described akin to shooting ducks in a barrel because it is so easy to find your target. Just swing your Sky-Watcher Dobsonian to the quadrant of sky to be searched, and scan the vicinity. The included 8 x 50mm right angle optical viewfinder provides both magnification and light-gathering to help narrow your search. The standard-equipment backlash-free 2" Crayford Focuser insures ultra smooth focusing adjustments, and the multi-coated, 4-element Plossl eyepieces (25mm and 10mm) provide a spacious 52 degree Apparent Field of View.

    To ensure mechanical ease-of-use, Sky-Watcher USA uses a high-performance Teflon bearing system in both axes, combined with tension adjustment in altitude to facilitate setting the appropriate amount of friction, assuring smooth vertical and horizontal manual movement without free-play from small bumps or gusts of wind. This also eliminates the need to have a balanced optical tube as in an equatorial mount. Sky-Watcher's Teflon bearing system is preferable to the use of ball-bearings. Ball-bearings make unintended movement of the optical tube more difficult to control. Fortunately, at low power, deep-space objects leisurely drift through the field of the Sky-Watcher 10" Dob, so constant mechanical adjustment of the telescope's orientation isn't needed to keep objects in the field of view.

    Sky-Watcher's revolutionary truss-support concept allows the optical tube's front and back cells to collapse together, aligning on the truss support rods which can then be locked down for easy and secure telescope transport. This one piece, low-hassle OTA design is mechanically simple and results in large aperture telescopes that can be reasonably handled and transported by one individual. This innovation gives Sky-Watcher users tremendous functional ease-of-transportability.

    The Sky-Watcher Dobsonian Telescope Uses Quality Components Throughout

    The Sky-Watcher 10" Dobsonian utilizes quality components throughout. Pride of workmanship manifests itself in high quality standards of optical and mechanical fabrication. The polishing process for primary and diagonal mirror yields smooth mirror surfaces ensuring good contrast, and properly corrected optics show minimum alterations to the optical wave-front.

    Aluminum is vacuum-deposited to the front glass surface on each primary mirror and elliptical diagonal mirror and then over-coated with hard quartz (SiO4). Additional layers of Titanium Dioxide (TiO2) and (SiO4) are then applied. Dust covers help keep your telescope clean when not in use.

    The mechanical and structural components of the OTA exhibit rigid construction and outstanding stability. The mount construction is sturdy and rigid. Mount design, while simple, facilitates smooth motions about both axes. Quality accessories enhance the observer's viewing experience.

  • specifications

    Aperture257 mm (10")
    Camera/Eyepiece Connection2" Nosepiece
    Dawes Limit0.46 arcseconds
    Focal Length1200 mm
    Focal Ratiof/4.7
    Free ShippingYes
    Glass TypeBorosilicate
    Highest Magnification514x
    Light Gathering Power1348x
    Limiting Magnitude15.8
    Optical DesignDobsonian
    Secondary Obstruction64mm
    Tube Diameter289mm
    Tube Length1118mm
    Tube Weight33 lb
  • included items

    • 10" f/5 Dobsonian Telescope
    • 8 x 50 RA Finderscope & Bracket
    • 2" Crayford Focuser
    • 1.25" Adapter
    • 10mm Plossl Eyepiece (1.25")
    • 25mm Plossl Eyepiece (1.25")
    • Dust Cover
    • Eyepiece Tray

Product Reviews

Customer Reviews
4.8 Based on 4 Reviews
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Filter Reviews:
    Kevin C.
    United States United States

    First Large Telescope

    Sky-Watcher 250P Flextube 10”. This is my first large scale (large scale to me) telescope. I’ve had the smaller aperture style but this my first big one. Just from first impression I can say that I am totally satisfied with my purchase. I haven’t used it enough yet for a full over all review. As far as receiving and assembly, it was great. I received it within a week of ordering. There is a video on YouTube for the assembly which was perfect. It looks awesome put together. I did use it one night. I saw Jupiter and was able to see the orange stripes around the planet. I was also able to see four of the moons. I will have to look again to see if I can see the big red spot. I got very good images of our moon. After a while of more usage I will leave a better update of my experience with the telescope.


    Beautiful looking.

    Once I got the scope out of the packaging, my jaw dropped. It's a stunning piece of work. White trim with a deep clear coat with sparkling black finish. Fit and finish is very good. I would give it a 5 star rating for ease of use, but collimating the scope was and is an issue. I can collimate a dob in two minutes easy. I even bought a Hotech laser for it and my 10 " Schmidt Newtonian. After ten minutes or more and multiple times, I have yet to be able to get the laser point in the middle of the donut. It gets right on the donut ring and jumps off. I got it aligned the best I could. Gave it first light and still was impressed with the view. M57 was stunning. M15 was very nice. Saturn was pretty good and I'm betting it too would be stunning had I been able to collimate it correctly. Maybe some knobs from Bob's Knob's will help? Not giving up. It's a beautiful scope and is going to my granddaughter as a gift. Since nothing was said by the other two (at this time) I assume they have no issues with this subject. I would still recomend it. It will Collimate, it may just need breaking in. Oh, and the focuser is smooth and easy to use. Having used Dobs from other manufacurers in the aproximate price range, their focusers are occasionally not as smooth and are quite clunky on some scopes.

    Tim R.

    Quality Throughout

    I'm fairly new to astronomy, so this isn't a review of optical quality. I have little viewinbg experience to use to rate the optics. Obviously, the views at first light were breathtaking compared to the 80mm refractor I started with. I was most impressed with the packaging. The boards of the base weren't just wadded in place w/ peanuts, they were secured with carefully cut cardboard, and covered w/ dense thin foam to prevent scratches. All the parts were individually bagged in groups according to when they were needed during assembly. The supplied tools were up to the task and I did not need anything else to complete the base assembly in less than 25 minutes. One thing was missing: the three screws to hold the eyepiece holder. Easily fixed from my backup stock. Oh, and it would be nice if the manual came in the package. I found it on line and DL'd it, but would have preferred to have a quality copy. The OTA is beautiful, no scratches, shiny and very solid feeling. I had wondered just how sturdy the supports would be when extended, but I can see no wobble between the top and the bottom, even if handled a bit roughly. Did a rough check on collimation and it seemed close. I'll check it more closely when I go out for a full night of viewing. I suspect, if handled carefully, collimation should be a snap and alignment may survive several trips. I own a very small Geo Tracker with the back seat taken out. The OTA fits snugly from front to rear, sitting on two of the foam blocks that came in the packaging. The base sits beside it, and there is still room for my observing chair and my plastic gun-case in which I carry eyepieces, flashlights, compass, etc. A lot of careful engineering and attention to quality during manufacturing went into this package. I would definitely recommend this scope to other serious beginners. Save your money don't buy a little cheap department store scope. Invest in your hobby and get something you won't outgrow in a month. Tim


    Very good optics

    I was told by the nice people at OPT that this isn't a planetary scope, but I beg to differ: provided collimation is done right and the mirror is thermally stabilized, it puts up razor sharp planetary views, better than I've seen in refractors costing 8X as much. There's very little to criticize for the price except that there's a little more stiction in the bearings than I would like. Otherwise it feels like a well-built scope, and the optical performance is very, very good.