What is the most attractive feature of a collapsible Dobsonian?
Why, the collapsible tube of course!
That is exactly what the SkyWatcher FlexTube 250P is, but this is no traditional Dobsonian, it’s also a SynScan model which means it has GoTo ability.
A Dobsonian with a huge aperture, collapsible tube, and computerized tracking – what more could one want?
However, there are drawbacks to a collapsible tube, so before you cash in on this deal, know what to expect.
✔️ Best Feature: Collapsible tube
❌ Worst Feature: Collapsible tube
👌 Ideal For: Celestial Viewing, Stargazing, Lunar & Planetary Observation, DSO Viewing, Astrophotography, Beginners, Intermediates, Experts
- Optical Design: Reflector
- Aperture: 254 mm (10”)
- Focal Length: 1200 mm
- Focal Ratio: f/4.7
- Eyepieces Included: 25 mm, 10 mm
Our Verdict: The FlexTube 250P SynScan is a champ! It’s a Dobsonian on steroids for those who want it all – a space-saver, large aperture, excellent viewing instrument, astrophotography possibilities, and of course, GoTo.
Who is the SkyWatcher FlexTube 250P SynScan Best Suited to?
The FlexTube is not a beginner’s Dobsonian as there are more than a few things to know before you attempt to tame this beast. But, for the “beginner” that has had some experience and wishes to invest in a serious buy as their next scope, the FlexTube is a viable option.
However, this setup is best suited for intermediates and experts that know how to collimate a Newtonian, care and protect for an open and exposed optical system, and are familiar with how GoTos function. Since it’s also capable of astrophotography, imaging skills can be developed with the FlexTube.
How Does the SkyWatcher FlexTube 250P SynScan Perform?
The FlexTube 250P is one of the best Dobsonian telescopes and worth every penny. There is little to complain about if you already understand the pros and cons to collapsible Dobsonians. It’s a “fast” telescope that will require the use of a Barlow lens, but it comes with good accessories that won’t need upgrading any time soon.
You’ll be able to see some stunning views of local bodies and their features including Mars and Jupiter, and Saturn’s moons with ring separation and more is visible with stunning clarity. Outside of our solar system, you’ll have good double star separation, excellent color fidelity on clusters, nebulae, and galaxies – and all this with the stock eyepieces!
There is a lot to explore, and the 10” Dob will turn you into an Indiana Jones of deep space over time.
Features & Benefits
The Flextube is a patented design that involves three metal struts that allow the “tube” to, well, collapse. It’s super easy by adjusting some knobs, the struts, and voila – done and done. When extended, T-clamps lock them in position and the setup feels secure.
The tube retracted is only 31.5” long and fully extended is 44”. The collapsible feature saves you approximately 12” of space. Even retracted, it’s still a long OTA and with accessories attached, it’s not very lightweight weighing in at 33 lbs. The base is 39 lbs, so transporting the Flextube proves to be about the same as transporting a traditional Dob with the only benefit of the tube collapsing down to save almost a foot of space.
The FlexTube 250P has a large 10” primary parabolic mirror, a 1200 mm focal length, and fast f/4.7 focal ratio. The parabolic mirror is a must-have for such a fast Newtonian telescope, and with a large aperture, crisp views are essential. What helps with the bright views is the FMC (Fully Multi-Coated) reflective coatings on both the primary and secondary mirrors.
It has a 2” Crayford focuser and a 1.25” adapter, 9×50 straight-thru finder, and it comes with two super wide-angle Plossl eyepieces (25 mm and 10 mm). The wide-angle viewing, fast optics, and 10” aperture makes for a great deep space searcher and stargazer. Be prepared to see more and seek out more. If practice is what you need to reach out to identify Herschel 400 or 800 catalogs, you may be able to achieve it with this Dob.
The base is a like a typical Dob that weighs a ton, is easy to assemble and use, is reliable and strong, and it stands on the floor. Interestingly, it does without azimuth roller bearings and instead incorporates three Teflon pads which is a simple design that’s smooth and sufficiently stiff at the same time.
As expected, friction between the side boards and the OTA can be adjusted via the threaded locking handles. Everything has been thought out well while maintaining the simplicity of a Dobsonian mount.
GoTo with Dual Encoder
This SkyWatcher Dobsonian is set up with GoTo capability. This model is more expensive than its non-GoTo counterparts since it has the SynScan AZ hand control. It has dual axis tracking, built-in WiFi control, 10 slew speeds, and requires a 12V DC power supply, but it comes with all the necessary cables to power everything.
Perhaps the most beneficial feature of the GoTo system, other than its ability to track smoothly and accurately, is its Dual Encoder Design. This is the ability to slew the OTA manually without interfering with the GoTo alignment. Of course, when you’re ready for imaging or for finding objects within a 42,900 object database, the SynScan AZ hand control is ready to get you there.
Imaging is definitely a possibility with the FlexTube 250P. Traditional Dobs may have the optics for imaging, but their mounts are limiting because they’re incredibly designed for visual viewing only. Having this Dob already setup from the get-go with a motorized and computerized mount makes it easier to pull the trigger on it.
Excellent color fidelity and resolution is in order for imaging. With the dual axis mount, you can track an object and experiment with short focus astrophotography. With a wide-angle, high-quality eyepiece and a strong Barlow lens, planetary imaging will prove to be possible.
What about long exposure photography? Without EQ movement, field rotation will turn those point sources (stars) from dots into arcs. You may want to consider de-rotation correction software to manipulate your images.
For the very reason you like the FlexTube, it may very well be the reason you take a pass on it. But, the disadvantages of a collapsible tube are still outweighed by the benefits. Some of the drawbacks include the obvious – open and exposed optics. Open optics are nothing new to Dob owners, but the fact that there is no extended tube between the mirrors means you’ll need additional dust caps for both pieces.
You’ll also find that it may need collimation more often than traditional Dobs simply because the struts that enable the collapsing ability are not as solid as a tube. Additionally, stray light can interfere with visual and imaging quality. There are shrouds you can buy or make to solve this issue, or you will be forced to buy high quality eyepieces to get the best seeing quality.
Can the FlexTube Telescope be Used for Terrestrial Viewing?
The FlexTube is not set up for terrestrial viewing, not only due to its optical orientation, but due to its size and purpose. It’s not a convenient setup for hauling to the rifle range or for bird watching. It may also have issues with reaching focus with a diagonal. This telescope is designed for celestial viewing.
Is the SkyWatcher Collapsible Dobsonian Easy to Transport?
The FlexTube with its collapsible tube design is actually bulkier and may be heavier than their traditional counterparts. The convenience comes with the retracting and extendable “tube” that helps to save space during transport or storage.
The 10” FlexTube with the tube retracted can fit on the backseat of a sedan, but you’ll also have to make room for the mount. Due to the design, it’s convenient to carry due to the two pieces, so you don’t have to disassemble the OTA into parts. But, it’s the weight that may get you. Between the 33 lbs for the OTA and the 39 lbs for the base, you’ll have to be able to lift that kind of weight to get from point A to point B whether it’s the backyard or a remote location.
Does the SkyWatcher FlexTube Telescope Need to be Collimated Often?
The FlexTube is designed to hold collimation once it’s been set up, but you will have to collimate it to get to that point. Some have retracted and then extended the tube to find that it held collimation, but it’s not always the case, so be prepared to collimate it every time you transport it. The three struts can be moved out of place during transport or when collapsing it, so it’s not as dependable as a solid tube. Think about it this way – you’re about to get really good at knowing your scope and collimating it!
Does the FlexTube 250P SynScan Need a Power Source?
The SynScan hand control and motor drive does require a power source to operate. A 12V DC power supply is recommended. Because it’s larger, it’s going to use a lot of power. However, you can use the FlexTube manually to save power or to do some sky-searching on your own.
The FlexTube is one of those buys where you will not experience buyer’s remorse.
It has everything from a collapsible tube to GoTo capability on a Dobsonian setup. It’s more expensive and bulkier than its traditional counterparts, but for the added features, it’s worth it.
Beginners, welcome to your first “serious,” high-end telescope buy. Intermediates and experts – travel with this Dob, snap pics, and have fun!