StellarDrive™ EQ8/EQ8-R Pro

StellarDrive™8-R Pro - £999.00
(Stated price is for upgrade/tune to customers own mount)

DARKFRAME StellarDrive™ EQ 8 Series Mounts are also available from new!
(Sky-Watcher Eq8-R Pro) - see New Built to Order mount page

It's your Mount. But Better.

Our StellarDrive™ EQ8/EQ8-R Pro is perhaps the ultimate iteration of a tuned EQ8/HDX110 Class mount. It has all the technology of our celebrated StellarDrive 6 and 6R, plus the inclusion of an higher grade precision RA worm-gear over the stock item, as well as other re-processed components. The result is a further reduction the EQ8 series mounts periodic error to circa ±5 arcsec, and down to 0.2 ArcSec Guided when conditions allow, a consistent 40-80% improvement over a stock mount. If you are an EQ8/Pro owner with a long focal length telescope, this is the path to much longer exposures, essential for deep sky! The smoothed PE curve the new StellarDrive-SPX™ gear train making guided tracking of any mount more precise. No need to upgrade to a higher payload or more expensive mount.

Check out how our StellarDrive™ 8 mounts compares in our performance charts.

Image: StellarDrive EQ8 with 45kg telescope array. Total payload running circa 0.55 ArcSec RMS, with up to 30min images. The Orion HDX110 is mechanically the same mount.

Our tuning methodology provides a more detailed approach, using higher performance lubricants that help the mount perform better, which have been tested extensively over several years. 
We also clean up the castings and can upgrade the worm-gear bearings for a better drive response and guiding ability...


If required, we can also upgrade the main DEC and RA axis bearings as an option, but this is rarely needed if the mount is new, as they only rotate 180º. We also load test the mount and take sound profiles, as well as stripdown/rebuild photos and video as part of the tune-up record.


We can prove the difference tuning makes.

Servicing, repairs, customisation and Tuning is available for Sky-Watcher EQ GOTO mounts using OEM parts. Unlike most manufacturers, we publish our customers data!

StellarDrive™ EQ8/EQ8-R Pro Series Notes:

The EQ8/HDX110 mount typically runs at 20-30 arcsecs from new unguided in independent tests. Once tuned and rebuilt our mounts run circa ±5 arcsecs, and less than circa 0.3 arcsecs guided is often reported by our customers. Also the mount will run smoother and much quieter especially once belt driven. This mount responds well to a rebuild and wipes 7-10 decibels off the slewing noise. In PHD2, your StellarDrive mount is up to four times as responsive to guide commands. The micro-changes have to be super-reactive in order to achieve a stable and reliable mount. Backlash is virtually eliminated, which also improves pointing accuracy.

The main difference between the StellarDrive 8 and our Standard StellarTune is our proven StellarDrive-SPX worm-gear super-finishing technology which is far more precise than a cut gear, meaning a smoother and potentially lower periodic error. Both RA and DEC axis worm-gears are upgraded.

The RA/DEC StellarDrive SPX worm-gears just spin freely when upgraded with our new treated and tested Hybrid Ceramic bearings. These reduce the end-float too, and provide a very solid feel to the mount, which in turn aids tracking control. We calibrate the end-float to an accuracy of 0.01mm, to ensure a consistent dial-out of backlash and minimised play in the gear-train. Other bearing surfaces are re-worked to improve conformity and to reduce friction and improve smoothness. As with our tuned EQ6's, periodic error has been reduced , and the StellarDrive 8 promises an even lower PE with a smoother sine-wave path that can be easily guided. The will result in a super low guiding error of just circa 0.13-0.2 arc-seconds RMS under PHD2 (weather permitting).

A StellarDrive™ EQ8 Mount also sports custom product badges and a Upgrade Certificate and unique serial number, as a well as a 2 year RTB warranty.

StellarDrive EQ8/EQ8-Pro Performance:

When compared to the new Sky-Watcher EQ8-Rh Pro, a StellarDrive EQ8 or EQ8-Pro, is just as reliable as any mount with high-resultion encoders. Why? Because the tracking amplitude is reduced, which almost matches what a high resolution encoder does. By improving the surface finishes and improving the tolerances, one can have a mount that can track equal or lower than our benchmark 100.14% of sideral rate, unguided. With guiding, it means that fewer, smaller commands are needed for error correction, and are for atmospheric conditions instead of compensating for mechanical error. 

We have over thirty Reference mounts worldwide that are utilised to constantly improve our Zero Drop Frame tuning methodology, and demonstrate the benefits of enhancing the mount. That's the point, you can do more imaging with our mounts. The same applies to your EQ8/EQ8-Pro.

Here is a customer supplied PHD graph of one of our EQ8 Mounts to (Build Type: Bonneville 6.3.5.2) which is the basis for our StellarDrive™ EQ8 mounts. The aim was to improve both unguided and guided performance and the new worm-gear does this. As part of our R&D we discovered other things we could do to improve the mount.

Image: April 2018 - StellarDrive EQ8 (2015 model) running 0.33 arcsecs RMS guided (0.22 in RA, 0.25 Dec in London!) Our DarkFrame (Build Type v6.3.2.2 and v6.3.5.2) offer reduced tracking amplitude and flatter graph, to about ±0.25 ArcSec under good seeing. Previously this EQ8 ran typically between 0.7-1.2 ArcSec RMS with greater amplitude. Payload was Orion Optics UK CT12. The mount has now run in and providing 0.33 RMS pretty consistently from its location in Greater London.

StellarDrive™ improves your EQ8 and offers reliable full payload tracking, without the need of an expensive upgrade and learning a new mount platform. 

Other customer supplied data is available upon request.

E&OE - Mount Build Specification and components used subject to change without notice. Example EQ mount tracking performance is not guaranteed, and is subject to the age and condition of the Donor Mount.