If you have a Dobsonian telescope (colloquiallly, a Dob) then the SkyStopper is right for you. It slowly tilts your telescope from East to West, over a period of about 90 minutes, so that your telescope will follow the stars as the earth rotates. It counteracts the effect of the Earth's rotation.

The SkyStopper Equatorial Platform is like no other. It works very well at Canadian latitudes, thanks to the arrangement of bearings.

The latin word for 'Sky Stopper' is coelostat, which is used to focus the sun onto a stationary telscope. SkyStopper can do that, but also much more. SkyStopper will move your telescope so that you can see the stars stand still in the eyepiece view.

Features and Capabilities

On the Resource page are links to various useful things, including the current revision of the User Guide and instructions. Also some useful information if you have an IntelliScope control. SkyStopper is also fullly compatible with Argo Navis digital sensor units. Resource Files

Technical Details

Price List

The SkyStopper Equatorial platform brings immense advantages. It makes your Dob a joy to use. Just look at some of the praise it has received...

Hi Steve, I just wanted to thank you for making such a great product. After 10+ years of observing with my dob and no tracking my observing sessions over the past 8 months (>20 sessions) have become so much more enjoyable. Of course this would not be possible without a platform that works as well as this one. My tracking time is borderline crazy at 90 min but my XT10 has yet to slip on the platform even in some very heavy dew conditions.

Just eyeballing Polaris along the center of the platform has resulted in extremely accurate tracking at x200. The remote is such a treat for centering and correcting small errors in tracking. Setup and take down of the platform is a snap in less than 60 seconds. The help that I received during my first month or so was customer service at its best.

One more thing, I just recently had the opportunity to travel to a location that was almost 2 degrees North of my home location. The instructions indicated that I should lower the South end by about 15 turns. This turned out to be spot on for tracking! Eric Shepherd Hamilton, ON, Canada

Not only is your SkyStopper custom made for your telescope dimensions and preferred observing latitude, it has features not available on any other equatorial platform at any price.

The allure of a large Dobsonian telescope is its large light gathering ability, and it allows high magnifications. Such a large mirror is impractical on a tripod or equatorial mount. An equatorial platform gets the best of both worlds. The Dob's existing construction maintains its collimation and rigidity, and the platform gradually follows the sky without any counterweights, and without having to change the way the Dob works.

Your big Dob will be completed by the SkyStopper. Your Dob will remain on target for up to 90 minutes, while you work on a sketch, check star charts, allow others to have a look, or just enjoy and inspect the view yourself.

You can seek targets at magnifications others can only dream about.

If your telescope has digital setting circles and/or alt-az drive capabilities, the SkyStopper is compatible with them.

You can use your Dobsonian Telescope for astrophotography. There's no eyepiece rotation with a SkyStopper. Your camera's time exposures are limited only by your camera electronics, the overall 90 minute travel time, and your telescope's sag. That's where guiding is useful. Attach a guide scope to your Dob, and with freely available software, you can fine tune the SkyStopper's actuators and right-ascension speed, to keep your target centred. Thanks to the SkyStopper's triple axis guiding, there is minimum or no rotation even at large guiding excursions.

Every SkyStopper is custom made based on the measurements of your telescope and weight. It is also custom made and calibrated for your preferred latitude, but can be used up to 5 degrees north or south of that latitude, with some easy to calculate adjustment to the angle of the base in the north-south direction.

The SkyStopper is motorized, and balanced for your telescope. When it is time to rewind, the motor accelerates into full reverse bringing the SkyStopper back to its starting point and ready for another 90 minutes of observing. You can also quickly rewind it or center it anytime, especially before you are planning to seek a new target.

The SkyStopper motors and guiding actuator and controller are all incorporated into the movable rocker platform. There are no wires to connect to the base when setting it up. If you pick up the rocker plate, the base stays on the ground as an independent piece. A quick release magnetic coupling connects the rocker to the base.

The SkyStopper geometry provides the most accurate tracking possible, and the computer compensates for the small speed variation due to tangent arm connection.

The SkyStopper has a pole-tune mode, where you can center a star or lunar crater in the direction you plan to observe, wait a minute and re-center it using the controls. Your SkyStopper will then track the object by extrapolating those guide motions until you slew the platform. That way you get the best tracking on your destination even if your polar alignment was a bit off. This centering depends on the direction the scope is pointed, so you would need to repeat it if you seek another target.

You control the SkyStopper via an included IR remote control. The SkyStopper software receives the signals and executes the commands. It can be configured to beep to indicate when commands have been received.

If you forget to bring your remote, there is a pushbutton on the SkyStopper main control unit which can be used for quick rewind, and to change the rate to track the moon or solar speed. All basic functionality is accessible from the button.

Select natural wood grain finish (we use waterproof baltic birch plywood throughout) or varnish it yourself when you receive it. You can also request a factory paint job or custom finish, applied before the parts are assembled.

Your SkyStopper will give you many years of dependable service. It will bear the weather much more stoically than your telescope and it will disassemble into 2 lightweight parts for transport.

Your SkyStopper comes standard with a compass and pre-calibrated bubble level to make setup in your preferred location easy.

All new SkyStoppers are equipped with a new controller design. It allows USB control of your SkyStopper and has easy software update capability. Additional sensors and microstepping help it to do an even better job than the original controller. (Plus it's easier for me to make them). The new controller can show status information on a pc terminal via USB, and is located very close to the main drive motor. This allows braces to be attached to the platform along the edges, if you want it to be extra strong.

The regular size SkyStopper works on very large scopes. It can also be made with double layers of wood, extra large, etc, to accommodate your huge scope. There's no comparison to a tracking platform for a big dob. The smoothness will show at the eyepiece.

Message added on May 15, 2016: I am still in production, on a part-time basis, as my day-job has taken more of my attention lately.

I have been getting a few inquiries about shipping times for SkyStoppers, so I have decided to clarify that here. I do not expect every inquiry to become a sale, but this websites purpose is to answer most casual questions. Accordingly, I will simply explain it here.

I shipped 2 SkyStoppers from the previous batch last week, one on the Monday before the transit of Mercury, and one on the Thursday before. I thought of some design improvements during production, so I communicated with my customers and they agreed to wait for the extra time until the improvements could be retrofitted to their almost completed units as well.

This is consistent with my desire to always ship the best possible and most modern version. I have 2 more SkyStoppers ready, which simply need to be star tested, boxed up and shipped. When that is complete, I will start the next batch.

Each step in the process of making a SkyStopper has to compete for the tidy space in my shop. Work in progress crowds the tools and benches, so I only make one batch at a time, synchronized. During the most recent batch, I received 2 new orders for SkyStoppers which I will soon begin. Allowing for delays, those will complete approximately the end of June.

No payment is required until the shipment date, but if your measurements are not on file when I plan the batch, that means you missed the batch. I begin a batch as soon as the previous batch ships, contacting all customers who have expressed interest AND provided measurements, and allow them to get on board. There is no obligation other than the effort they put into providing the measurements. After they have responded, any planned price increases go into effect for new orders.

I often make extra SkyStoppers with similar dimensions, during a production run, and sell them if someone happens to provide compatible measurements. If your measurements are on file, i might offer you a ready-made unit on short notice, which is a match for your needs. Otherwise, i will put them on Canada-Wide when time permits me to complete them. Of course, active orders get precedence.

You might wonder why I do not use skystopper.com. A domain name broker has offered to hold it and ensure none of my competitors buy it; I dont need it. Anyone who uses google will find this site.

I respond to inquiries very quickly since I am developing software at my desk when not fashioning SkyStoppers. Contact me with any questions. I am Stephen Germann, at smrg@cogeco.ca. SkyStopper is made by Ekasilicon Technology Ltd, in Burlington Ontario Canada.

Rest in Peace, John Dobson, who died on January 15, 2014 at the age of 98.