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All-Star Telescope is your source for all things astro from telescopes to astrophotography cameras. Have a question? We'd love to help. Email: Call Us: (587) 336-6621 Toll Free: 1 (866) 310-8844
Have a question? We'd love to help. Email: Call Us: (587) 336-6621 Toll Free: 1 (866) 310-8844

Sky-Watcher Flextube 250P 10" Collapsible Dobsonian Telescope (S11720)

SKU 050234117203
Save $75.00 Save $75.00
Original price $1,355.00
Original price $1,355.00 - Original price $1,355.00
Original price $1,355.00
Current price $1,280.00
$1,280.00 - $1,280.00
Current price $1,280.00

Shipping Available to Canada and USA from Edmonton Warehouse.
International shipping available by request. Contact Us

Usually ready in 24 hours

All Star Telescope's Take

Dobsonian telescopes are some of the best beginner telescopes available. They're simple to use, and open the night sky up to everyone. These scopes will give incredible views of the planets, mind blowing views of the moon, and some really interesting views of deep sky objects like galaxies and nebulas. For a bit of context, the human eye is capable of seeing approximately 10k stars on it's own. That number goes up to 50 Million when you use this 10 in dobsonian telescope.  You'll neve outgrow these scopes, they are perfect for visual astronomy.


For decades, the Dobsonian stood as a DIY staple of amateur astronomy, usually constructed with two mirrors, a tube and a base. Often referred to as '˜light buckets', Dobsonians provide users with the highest possible aperture for their money when compared to telescopes of a similar size, such as Schmidt-Cassegrains or refractors.


Developed in the 1970s, the Dobsonian-style telescope is an inexpensive solution for bright, detailed visual observing using a simple design. The name '˜Dobsonian' comes from the telescope's inventor, John Dobson, a Vedanta monk who popularized sidewalk astronomy and dedicated his life to astronomy outreach. Dobson was well known for constructing large aperture reflecting telescopes capable of deep sky viewing, using low cost materials. These were often made with found materials, heavy cardboard tubes, recycled porthole glass, and plywood mounts. Dobson, who literally wrote the book on how and why to make amateur telescopes, encouraged other astronomers to assemble their own telescopes and taught workshops on telescope making.

The Flextube Dobsonian innovates on that original design, offering users the ability to collapse the optical tube using a proprietary truss-tube system while retaining its collimation. The optical tube uses a parabolic primary mirror, constructed of borosilicate, then polished and coated with our proprietary Radiant Aluminum Quartz (RAQ), producing a remarkable 94% reflectivity. With a 10-inch aperture, the Flextube 250P Dobsonian collects 1235 times more light than the human eye! This simple yet effective design is perfect for visual observation of faint objects, such as nebulae, star clusters, and galaxies.

Supporting the Flextube Dobsonian is more than just a simple rocker box. The base uses Teflon bearings for smooth, easy Azimuth slewing and a patented tension control handle to lock the telescope in place. Once locked on an object, the telescope can support both 1.25-inch eyepieces as well as the heavier 2-inch eyepieces, allowing you to use virtually any eyepiece on the market. All Flextube Dobsonians come with a slew of accessories, including: two 1.25-inch eyepieces, a 1.25-inch eyepiece adapter, a 2-inch eyepiece adapter, dust caps, and a 8x50 finderscope.

At Sky-Watcher, we stay true to the traditional John Dobson design, while offering a fresh look for the 21st century. Although we love computerized telescopes, using a star chart to find objects by hand can be far more fulfilling and will improve your knowledge of the night sky. Unplug your electronic devices, step outside, and become immersed in the wonders of the universe.

Quick Overview

  • Large 250mm aperture delivers stunning viewing experience
  • Innovative collapsible design that retains collimation
  • 1235x more light-gathering power than the human eye
  • Patented tension control handle allows for precise slewing and maximum stability
  • Parabolic primary mirror with Radiant Aluminum Quartz (RAQ) coating for 94% light reflectivity
  • Heavy-duty rocker box with Teflon bearings provide a stable base with smooth motion
  • 2-inch Crayford-style focuser with 1.25-inch adapter allows for use of nearly any eyepiece

What's in the box

  • Optical tube assembly
  • Base
  • 8x50 RACI finderscope
  • 25mm eye piece
  • 10mm eye piece


Optical Info
Optical Design Newtonian
Mirror Coatings Radiant Aluminum Quartz (RAQ) coatings with 94% reflectivity
Glass Type Borosilicate
True Aperture (mm) 257
Primary Aperture (mm) 254
F/Ratio 4.7
Focal Length (mm) 1200
Secondary Diameter 64mm
Secondary Obstruction (by diameter) 25%
Secondary Obstruction by Area 6%
Observational Info
Dawes Limit 0.46
Rayleigh Limit 0.55
Limiting Mag. 14.5
Minimum Magnification 36
Maximum Magnification 500
Light Gathering (compared to next size down) 57%
General Info
Focuser 2" Crayford
OTA Length (Retract/Ext.) 31.5"/44"
OTA Outer Diameter 11.375"
OTA Weight (with accessories) 33
Dob Base Weight 26.5
Dob Base Measurements 29.5"x20"
Zenith Eyepiece Height 48"
Included Finder 8x50 RACI
Included Diagonal No
Included Eyepieces 25/10 Plossl
Magnification w/ Included Eyepieces 48x/120x
Included Case No
Corrector No



Customer Reviews

Based on 1 review
Marty Harder
Still familiarizing

Have set up everything….i love the charcoal metallic optical tube finish…the collapsing tube also makes the unit much more transportable….really looking forward to my first outing…in the mean time i am researching and learning about my eye pieces and their capabilities and limitations as they are used with the 10” dob…really excited for that inaugural outing!!