Can Sky Watcher EQ8R mount load 16" Newtonian reflector and guide stably and precisely? - Forums

Topic starter

Feb 6, 2026

Hi everyone,

I am trying to DIY a 16” F4 Newtonian reflector with truss tube, and tend to use Sky Watcher EQ8R mount, in my remote observatory. The tube frame will consist of a truss tube for loading and an internal carbon fiber tube for shading mirrors. Here is the approximate specifications:

Design length: 1380mm

Max diameter (truss tube diameter): 550mm

Internal carbon fiber tube diameter: 450mm

OTA weight: 26kg (with Sandwich primary mirror 8kg)

Total weight with all equipment: ≈30kg

Center of balance: 290mm height, 1/3 of length

Observatory dome: 3.5m diameter

Based on these specifications, can any users of Sky Watcher EQ8R help me to estimate if it is competent to my 16” Newtonian reflector? Has anybody used EQ8R mount to load 16" Newtonian or other telescopes with the similar specifications? Since Sky Watcher does not clarify the torque of mount motor, I am not sure if EQ8R, with consideration into center of balance, can load 16” Newtonian reflector and guide stably and precisely. I fear the impact of wind on telescope, which may make guiding data bad. But I am planning to use an observatory dome for my gear, which may diminish the impact of wind and reduce the requirements for heavy load capacity mount.

Many thanks

Marshall

Helpful Engaging

SonnyE

Frequent contributor

Feb 6, 2026

No experiance here, Marshall.

But since you are under the weight rating, I wouldn’t expect any problems. (Short of a compressed disk or 5)

Good luck and enjoy! I look forward to some images.

alpheratz06

Feb 8, 2026

RH8 is given for about 50kg raw P/L.

30kg payload should fit without any problem IMHO.

ItsMeAstro

Feb 13, 2026

On paper RH8 handles 50 kg raw payload but certainly not in practice with a 16” F4 Newtonian reflector with truss tube as EQ8 has several flaws, the reason my EQ8 is upgraded with several upgrade kits to solve these problems for guaranteed accurate handling your reflector.

Watch this video with explanations of these flaws :

https://www.youtube.com/watch?v=-tCgPerq9cQ

Information about user-installable heavy-duty kits and my full upgrade, which also includes heavy-duty worm wheels and heavy-duty saddle, can be found here :

https://shibumi-astroengineering.com/astro-engineering-products-services/skywatcher-eq8-eq8-r-mount-modernisation/

https://shibumi-astroengineering.com/product/complete-mount-modernisation-certification-for-eq8-r/

Rainer Ehlert

Feb 13, 2026

ItsMeAstro · Feb 13, 2026, 07:32 PM
On paper RH8 handles 50 kg raw payload but certainly not in practice with a 16” F4 Newtonian reflector with truss tube as EQ8 has several flaws, the reason my EQ8 is upgraded with several upgrade kits to solve these problems for guaranteed accurate handling your reflector.
Watch this video with explanations of these flaws :
https://www.youtube.com/watch?v=-tCgPerq9cQ
Information about user-installable heavy-duty kits and my full upgrade, which also includes heavy-duty worm wheels and heavy-duty saddle, can be found here :
https://shibumi-astroengineering.com/astro-engineering-products-services/skywatcher-eq8-eq8-r-mount-modernisation/
https://shibumi-astroengineering.com/product/complete-mount-modernisation-certification-for-eq8-r/

I have to say that so much technique but they missed the opportunity to make it a floating worm assembly (spring loaded) with really NO backlash. A fixed position of the worm against the worm wheel will always have backlash (unless you polish the worm for 24 hours with polishing paste againt the worm wheel) 😀 but if you spring load the worm against the wormwheel you will really get a backlash free design. Changing the timing belt to a smaller pitch does not change anything as timing pulleys are designed to have 0 backlash.

IMHO

Tony Gondola

Frequent contributor

Exemplary contributor

Feb 13, 2026

We used to polish large diameter Byers worm and wheel sets like that. It really made a difference but standards where different back then.

Rainer Ehlert

Feb 13, 2026

Tony Gondola · Feb 13, 2026, 08:43 PM
We used to polish large diameter Byers worm and wheel sets like that. It really made a difference but standards where different back then.

I also did it on my late Losmandy Gemini G11 mounts … and then I designed in 2004/2005📷 LosmandyWorm_2.jpg a spring loaded worm years before Losmandy came out with his spring loaded worm.

📷 LosmandyWorm_1.jpg

Tony Gondola

Frequent contributor

Exemplary contributor

Feb 13, 2026

Rainer Ehlert · Feb 13, 2026, 08:54 PM
Tony Gondola · Feb 13, 2026, 08:43 PM
We used to polish large diameter Byers worm and wheel sets like that. It really made a difference but standards where different back then.
I also did it on my late Losmandy Gemini G11 mounts … and then I designed in 2004/2005📷 LosmandyWorm_2.jpg a spring loaded worm years before Losmandy came out with his spring loaded worm.
📷 LosmandyWorm_1.jpg

Beautiful!

ItsMeAstro

Feb 14, 2026

Rainer Ehlert · Feb 13, 2026, 08:41 PM
ItsMeAstro · Feb 13, 2026, 07:32 PM
On paper RH8 handles 50 kg raw payload but certainly not in practice with a 16” F4 Newtonian reflector with truss tube as EQ8 has several flaws, the reason my EQ8 is upgraded with several upgrade kits to solve these problems for guaranteed accurate handling your reflector.
Watch this video with explanations of these flaws :
https://www.youtube.com/watch?v=-tCgPerq9cQ
Information about user-installable heavy-duty kits and my full upgrade, which also includes heavy-duty worm wheels and heavy-duty saddle, can be found here :
https://shibumi-astroengineering.com/astro-engineering-products-services/skywatcher-eq8-eq8-r-mount-modernisation/
https://shibumi-astroengineering.com/product/complete-mount-modernisation-certification-for-eq8-r/
I have to say that so much technique but they missed the opportunity to make it a floating worm assembly (spring loaded) with really NO backlash. A fixed position of the worm against the worm wheel will always have backlash (unless you polish the worm for 24 hours with polishing paste againt the worm wheel) 😀 but if you spring load the worm against the wormwheel you will really get a backlash free design. Changing the timing belt to a smaller pitch does not change anything as timing pulleys are designed to have 0 backlash.
IMHO

Hi, Shibumi has developed and use a spring loaded worm assembly with no backlash as I have on my upgraded EQ8 and the video explains it .

Rainer Ehlert

Feb 16, 2026

ItsMeAstro · Feb 14, 2026, 07:56 PM
Rainer Ehlert · Feb 13, 2026, 08:41 PM
ItsMeAstro · Feb 13, 2026, 07:32 PM
On paper RH8 handles 50 kg raw payload but certainly not in practice with a 16” F4 Newtonian reflector with truss tube as EQ8 has several flaws, the reason my EQ8 is upgraded with several upgrade kits to solve these problems for guaranteed accurate handling your reflector.
Watch this video with explanations of these flaws :
https://www.youtube.com/watch?v=-tCgPerq9cQ
Information about user-installable heavy-duty kits and my full upgrade, which also includes heavy-duty worm wheels and heavy-duty saddle, can be found here :
https://shibumi-astroengineering.com/astro-engineering-products-services/skywatcher-eq8-eq8-r-mount-modernisation/
https://shibumi-astroengineering.com/product/complete-mount-modernisation-certification-for-eq8-r/
I have to say that so much technique but they missed the opportunity to make it a floating worm assembly (spring loaded) with really NO backlash. A fixed position of the worm against the worm wheel will always have backlash (unless you polish the worm for 24 hours with polishing paste againt the worm wheel) 😀 but if you spring load the worm against the wormwheel you will really get a backlash free design. Changing the timing belt to a smaller pitch does not change anything as timing pulleys are designed to have 0 backlash.
IMHO
Hi, Shibumi has developed and use a spring loaded worm assembly with no backlash as I have on my upgraded EQ8 and the video explains it .

Thanks, I saw at minute 17. The first time I saw the video I was doing two things at the same time and missed this. At my age I should only do 1 thing at a time 👍️👍️👍️👍️👍️

Well done and I take back what I posted earlier. Of course on a big mount like that it is easier to spring load a worm compared to a tiny asembly as on the Losmandy G11.

👍️

Respectful Supportive

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