A Great Start – Sky-Watcher 10″ Collapsible Dobsonian

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Are you in the market for an entry-level light bucket that’s capable of picking off the entire Messier catalog or are you new to astronomy and don’t want to break the bank on your very first serious telescope?  The Sky-Watcher 10” Collapsible Dobsonian just might fit both roles and leave enough money for a few accessories.

I’ve been an amateur astronomer for more than 20 years and I’ve used about everything from $100 manual telescopes to $20,000 fully computerized, self-guiding, astrophotographic workhorses capable of conducting serious science, but there is an elegance and simplicity to the venerable Dobsonian. Inch for inch and dollar for dollar they offer more bang for your buck that just about any telescope out there. Large apertures offer stunning views of the heavens while a simple mount helps keep costs low.

For those of you not familiar with the genesis of the Dobsonsian, it all started with a  Vedantan monk named John Dobson. John would quietly make telescopes out of discarded junk, grinding mirrors from old ships portals and making tubes from concrete forms. As the founder of the San Francisco Sidewalk Astronomers his mission in life was to share the night sky. He wanted to show people low cost ways to build giant telescopes capable of seeing very faint deep sky objects. I once heard John say that if you can’t sleep in it, it’s not big enough. With its humble beginnings the Dobsonsian telescope has evolved quite a bit. Now many use advanced materials, such as carbon fiber, CNC machined aluminum and low-expansion borosilicate glass mirrors.

Often referred to as a Dob, the Dobsonian telescope is simple. It is a Newtonian telescope (built using only mirrors) mounted to what is best described as a cannon mount, allowing side-to-side and up-down movements by pushing or pulling the scope in the desired direction. Since no computer or electronics are used, the user must guide the telescope by hand to compensate for the Earth’s rotation. This isn’t as difficult as it might seem, but does require a little practice.

Sky-Watcher has been a long-time player in the astronomy market. Their parent company, Synta Optical Technology Co., Ltd, also owns Celestron LLC and is a supplier to many other major telescope brands. It’s difficult to find a company who isn’t supplied or influence by this major telescope maker. Their rise to prominence is due in part to the quality products they supply. The subject of this review is certainly no exception.

Early Dobsonsians had one drawback. They were huge. The optical tube alone could be 4 feet long or more which made them difficult to store and transport. The rise of the collapsible dob was a major turning point in popularizing these capable instruments, but companies had varying degrees of success in implementing designs rigid enough to hold precise collimation while maintain portability. I can speak from some experience and will say there is nothing worse than having a scope where collimation changes. I didn’t find that to be the case here. In fact, I was quite impressed to have received the scope in near perfect collimation and it maintained it throughout roughly two weeks of frequent use and it still going strong.

The scope itself was collected directly from Sky-Watcher USA in two boxes. One contained the fully-assembled optical tube and the other contained the mount components. Both were well packed. If you’re remotely handy or have assembled anything from Ikea, you’ll be very comfortable building the mount. The instructions were simple and easy to follow. All the components were present and it was snap to assemble. I’ve assembled hundreds of telescopes, so I have a little experience, but I had this together in about 25 minutes. Once the mount build was completed, mounting the optical tube assembly was as simple as dropping it onto the teflon-like rollers and securing it with two threaded handles and inserting the viewfinder and an eyepiece. The telescope was well finished and had fine details. Painted surfaces were high quality and components were clean and free of defects, except for a couple very small cosmetics blemishes on the mount and optical tube. Although relevant to mention, they in no way affected my overall impression or function on the telescope. I would say overall quality was above average to excellent. A telfon-type material provides the bearing surface for azimuth pads and altitude rollers. Tracking was good. Starting the motion required a little more force, but once going the motion was relatively smooth and predictable. Additional pads might improve the feel of the initial azimuth movement.

Sky-Watcher uses a series of locks and detents to engage the truss tubes when extended to prevent collapse during assembly. This clever mechanism works quite well, although mine was a little tight out of the box,  after some adjustment they seem to perform just fine now.

Dual-Speed-FocusThe version of telescope I received has an upgraded dual-speed focuser that offers precise control and nearly imperceptible lash. I was impressed with the quality and function of the focuser. 1.25” and 2” eyepiece adapters were included. Both extend the focuser draw-tube significantly to provide enough back-focus for virtually all sizes and makes of eyepieces.

8-x-50-RA-ViewfinderAn 8×50 right angle finder is also  supplied.  The optics were crisp and clean. Focusing was accomplished with a typical helical thread for the objective lens and a lock ring. A nice touch would have been a rubber eye-cup on the finder, but this is a rather small omission. I could argue over the long run this piece would be the first to be damaged or lost, so it’s not the end of the world that it’s not included. Perhaps this is just a nice-to-have.

25mm and 10mm 1.25” super plössl eyepieces are included. Metal construction, captive recesses on the barrels and rubber fold-down eye-cups make these good quality eyepieces that are certainly adequate to get you started. Eye relief on the 25mm was comfortable, but it was tricky getting your eye close enough on the 10mm to see the field stops. Eyeglass wearers would struggle here. Image quality was good in both eyepieces.

Of course the optics are what we’re all interested in, right? Overall, I was quite impressed. As stated earlier, collimation was nearly spot on and I’ve felt no need to make any adjustments here. The trusses are not so long to contribute to instability of the fully extended telescope. I feel it’s appropriately rigid and holds collimation from zenith to the horizon. Astigmatism is well controlled and coma is about what I’d expect from an f/4.7 optical system. It’s present, but not distracting or excessive for a fast Newtonian. Being June in Southern California, we’ve not had many nights that weren’t interrupted by clouds, the result of a marine layer common at this time of year. I’ve yet to use the telescope long enough for the mirror to fully equalize with the ambient temperature, but even medium-powered views at 100-120x of Jupiter’s transiting moons were pleasing in spite of a mirror still giving off plumes of heat.

I’m rather surprised Sky-Watcher doesn’t offer a light shroud accessory for this product. I believe it’s an important accessory that improves contrast, reduces tube currents and contributes to keeping dirt and debris out of the optical tube. I made mine in about two hours. If you should choose to do this, you’ll need circular ribs in the shroud. There are only three trusses and if ribs aren’t used, your shroud will sag into the optical path. I also added a 16” stand underneath. I’m rather tall so a 48” eyepiece height at Zenith is a non-starter for me. Not only is it now a comfortable 64” at its highest, I have storage for eyepieces and a place to put the dust covers when not in use.

Having worked in the telescope industry for 15 years, I understand the necessity to use colors to distinguish brands. As this is a scientific hobby, I prefer function over aesthetics. I would have preferred a white optical tube and base. As with many amateurs astronomers, I set-up in the daylight and wait until darkness to observe. Dark colors simply absorb too much heat and one must wait for that heat to dissipate before image quality is at its best. A light colored optical tube would reduce the time it would take to accomplish this. Of course, Sky-Watcher is not unusual here. Meade famously used deep blue on their optical tubes and a number of Celestron products are black. In our modern world of brand marketing, it’s no surprise that brand identity trumps function, but a guy can hope.

SpecificationsIn conclusion I found the 10” Sky-Watcher Collapsible Dobsonian to be a high quality instrument and an excellent value. There are few telescopes as capable for the modest $699 price tag. The large aperture makes this a deep sky powerhouse, while the low cost put it within the reach of even the most modest of budgets. Of course, with no computer or tracking motors, the telescope can only find what the user can, but the lessons learned star-hopping your way around the sky will benefit a budding astronomer for years to come.    I can enthusiastically recommend this instrument to anyone seeking a modestly priced light bucket capable of providing many years of faithful service.

 

 

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About Author

Chris Morrison

Chris is an avid amateur astronomer, birder, photographer and general nature and science nut. He was a Vice President at a major telescope manufacturer, where he was directly involved in product development and testing for much of his 15 year tenure. His passion for all things science and nature is what led him to found localmeridian.com, an online outlet for his desire to share his love of the natural world.

4 Comments

  1. Avatar
    Celestron Telescopes on

    Hello there! This blog post could not be written much better!
    Reading through this article reminds me of my previous roommate!
    He continually kept talking about this. I most certainly will forward this post to him.
    Pretty sure he’ll have a great read. Thank you for sharing!

    • Chris Morrison

      I couldn’t find one that worked so I built the one pictured. I designed it to be at my eye’s height with the telescope at zenith. I would probably do it a little differently today and have since modified the feet to be stiffer and wider, so it’s pretty good now.

      Thanks for commenting.

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