Sky-Watcher Flextube 300P SynScan

At a Glance

• Aperture: 305mm (12-inch)
• Focal length: 1500mm
• Focal ratio: f/4.7
• Focuser: 2-inch single-speed Crayford-style, 1.25-inch adapter supplied
• Finder: 9x50 straight-through
• Mount: Computerised GoTo Dobsonian, dual-axis tracking, 42,900-object database

Product Overview

The Sky-Watcher Flextube 300P SynScan is a 305mm (12-inch) computerised GoTo Dobsonian with a collapsible truss tube. It pairs serious aperture — 1500mm focal length at f/4.7, gathering 1840 times the light of the unaided eye — with a SynScan hand controller and built-in Wi-Fi, so the telescope finds and tracks targets for you.

The truss tube retracts for transport and holds collimation through the cycle. It travels as two pieces, optical tube and rocker box, and goes together in seconds without disassembling the truss.

Who It Is For

This is a good match if you:

• Want large-aperture deep-sky views without hunting for every target — a 42,900-object database does the finding.
• Observe with others, where holding an object centred in the eyepiece while people take turns matters.
• Travel to dark sites and need 12 inches of aperture to fit in a vehicle.
• Like to star-hop sometimes — Freedom Find lets you grab the tube and move it by hand without losing alignment.

Key Features and Design

• 305mm parabolic primary at f/4.7: the fast ratio buys a wide true field for a telescope this size, suiting large nebulae and open clusters.
• 1840x the light grasp of the unaided eye: the aperture that puts structure into galaxies rather than just detecting them.
• Radiant Aluminum Quartz coating at 94% reflectivity: more light reaching the eyepiece from an already large mirror.
• Patented collapsible truss tube: retracts for transport and storage while retaining collimation, and provides back focus for camera use.
• SynScan GoTo with built-in Wi-Fi: hand controller plus wireless control, driving to any of 42,900 catalogued objects.
• Patented Freedom Find dual encoders: move the telescope by hand at any time and it stays aligned — no re-alignment routine afterwards.
• Patented tension control handle: adjusts friction between tube and sideboards to balance heavier eyepieces.
• Dual-axis tracking: sidereal, lunar, and solar rates on DC servo motors, with pointing accuracy published to 5 arc minutes.

Optical and Mechanical Design

Optically this is a fast Newtonian: 1500mm of focal length over a 305mm parabolic primary works out to f/4.7. A fast focal ratio gives a wide true field for a telescope this size, and it keeps the tube short enough that the eyepiece stays at a workable height. Working entirely with mirrors, there is no chromatic aberration at any magnification.

Mechanically, two patents do the heavy lifting. The truss system lets the upper cage slide down over the mirror box for transport and return to the same geometry on extension, which is why collimation survives. Freedom Find puts encoders on both axes reading position independently of the motors, so the GoTo system always knows where the tube is pointing even after you have pushed it there by hand. That combination — computerised pointing you can override without penalty — is what separates this from a motorised mount that punishes you for touching it.

Recommended Uses

• Deep-sky observing: galaxy groups, planetary nebulae, and globulars resolved across the core.
• Guided touring: the controller will run a tour of the best objects currently above your horizon.
• Outreach and club nights: tracking holds the target centred while a queue of people takes turns.
• Lunar and planetary imaging: tracking plus available back focus makes planetary camera work practical.

Compatibility and Accessory Notes

Supplied with a 9x50 straight-through finderscope, 12.5mm and 20mm four-element 1.25-inch Plössl eyepieces, and the SynScan hand controller. The 2-inch focuser takes any standard 2-inch eyepiece, with the supplied adapter for 1.25-inch — a wide-field 2-inch eyepiece is the first upgrade most owners make, and at f/4.7 a well-corrected design earns its price at the field edge.

Power is 10 to 15 V DC at 1 amp through a 2.1mm centre-positive plug, so a field battery or regulated supply is needed — worth sorting before your first dark-site trip. A light shroud over the open truss controls stray light and dew. A UHC or O-III filter lifts nebula contrast noticeably. If you would like help matching eyepieces, a power solution, or a shroud to this telescope, get in touch and we will work it out with you.

Good to Know Before You Order

• It needs power. The GoTo system runs on 10 to 15 V DC. A suitable field battery is essential kit rather than an optional extra.
• Deep-sky imaging is limited by the mount, not the optics. The collapsible design does provide back focus for a camera, and dual-axis tracking holds a target, but an alt-azimuth mount rotates the field over long exposures. Lunar and planetary capture is well suited; long-exposure deep-sky work is not what this platform is for.
• The truss section is open. Stray light and dew can reach the light path from the side, which a shroud addresses.
• This is a large telescope. Two pieces, both substantial. A wheeled dolly makes a real difference if it lives indoors between sessions.
• Cool-down matters at 305mm. Setting it outside well before you observe pays off directly in planetary detail.

Frequently Asked Questions

Is it difficult to set up?

The physical assembly is quick — extend the truss, seat the tube in the rocker box, connect power. The GoTo then wants a brightest-star or two-star alignment, which takes a couple of minutes and is menu-driven. Sky-Watcher notes that most people are comfortable with the controller within a few sessions.

Can I move the telescope by hand?

Yes, and this is one of its better features. Freedom Find dual encoders track position independently, so you can push the tube to a target and the system stays aligned with no re-alignment needed.

Can I use it for astrophotography?

For lunar and planetary imaging, yes. For long-exposure deep-sky imaging, no — an alt-azimuth mount introduces field rotation over long exposures regardless of how well it tracks.

What comes in the box?

A 9x50 straight-through finderscope, 12.5mm and 20mm 1.25-inch Plössl eyepieces, and the SynScan hand controller. You supply a 10 to 15 V DC power source.

How accurate is the pointing?

Sky-Watcher publishes GoTo pointing accuracy of up to 5 arc minutes, which places targets comfortably inside a low-power eyepiece field.

How is it different from the manual Flextube 300P?

Same collapsible concept and aperture class. This version adds DC servo motors, dual-axis tracking, the 42,900-object database, Wi-Fi control, and Freedom Find encoders. The manual version needs no power and costs considerably less.

Bottom Line

In short: a 305mm f/4.7 collapsible Dobsonian with computerised GoTo, dual-axis tracking, and encoders that let you push it around by hand without losing alignment. Bring a 12 V supply and give the mirror time to cool, and it will find and hold 12 inches worth of deep sky for you all night.