Belting The Skywatcher HEQ5 Pro

“If you own a HEQ5 then you know exactly the noise I’m on about. It’s horrible, it sounds nasty and doesn’t sound healthy at. all.”

Getting A Grip With Belts

The HEQ5 Pro is a fine mount. A fine mount indeed. It’s such a gateway Go-To tracking mount for astrophotographers. It came to me, highly recommended, second hand from a bloke in Birmingham. What a fun drive that was! I upgraded my EQ5 to a HEQ5 Pro SynScan Go-To Tracking Mount and boy was that a monumental day for me.

One issue is apparent with these mounts originally: graunchy gears.

The thing about spur gears (straight edge cut gears that interlink with one another) is that they’re noisy. It’s the same sort of gear in a car’s reverse, and we all know how loud reverse gears squeal.

But aside from the noise another, more insidious issue permits gear based systems.


You may have heard of this, it’s what your Periodic Error endevours to mitigate. Backlash is the tiniest of play inbetween gear teeth. Even with grease, over time these gears will wear themselves down and it seemed that was possibly the case with mine. My right ascension axis had loads of play between the idler gear and worm gear – you’ll see it in the video! It was crazy.

Clat. Clat. Clat.

I thought to myself that the sheer amount of backlash could also be responsible for my terrible PHD2 guiding.

So it was time to address that.

Addressing The Issue

Some amongst you may know of a small engineering shop just outside of Northamptonshire, UK. A shop called Rowan Engineering, and their astronomy department. They fashion a kit that fits the Skywatcher HEQ5 Pro and the EQ6 to replace the gear drive with a belt drive. Belts are superior as they either eliminate backlash and do wonders for PE & PEC, or it smoothes it out in a way that the PEC & guide scope have a much easier time managing it.

That, and it’s much quieter.

As Rowan Astronomy puts it “coffee grinder noise”. If you own a HEQ5 then you know exactly the noise I’m on about. It’s horrible, it sounds nasty and doesn’t sound healthy at. all.

For a modest cost (modest within this hobby that’s for sure) they supply a full kit of gears, a spacer, belts, allen keys and bolts. Pay a bit more for a pinion extractor. You’ll thank me later.

Replacing The Gears For Belts

So with the patient ready, all my bits nicely knolled on the tidy table and a clear mind (and the instructions), I stared down the mount and did battle with the inner gubbins.

I didn’t exactly even need my mechanical know-how though. In all honesty it was really easy. The instructions supplied by Rowan Astronomy are top notch and super easy to follow.

You will need:

  • All the allen keys included in the kit.
  • A pinion extractor (you did remember to buy one, right?)
  • Some cleaning solution (isopropyl alcohol works – or nail polish remover in my case)
  • Some tissue
  • A phillips head screwdriver
  • A flatblade screwdriver

Really, most households will have everything on hand. The only thing that isn’t included in the kit is the cleaning solution and the screwdriver.

You’ll need the phillips screwdriver to take the front and side covers off. The alcohol to clean the old grease off (grease and belts don’t mix), and the flatblade screwdriver for a bit of prying and persuading.

Other than that just take your time, follow the instructions and for heaven’s sake:

Note where the wires are for the Declination Motor and the RA motor. They are different and the instructions only shows the Declination Motor.

If you’re familiar with tinkering, or a mechanical background and just feel confident then chances are you’ll get this done in about 45 minutes I’d say. An hour if you’re also recording a video.

If you’re not used to fiddling with fixtures and fittings within highly precise technical machinery that costs a decent amount of money, then just take your time. Like astronomy, you have all the time in the world to take. Go slow, read the instructions and you’ll get there.

Side Panel Removed HEQ5 Revealing The Belts
The SW HEQ5 Pro After Its Belt Mod

The Verdict

Admittedly I need more time with it. But initial results are great. Even though the second chart did have a refractor on it instead of a newtonian, I have little doubt that the chart would be all that much different.

The mount is so much more quieter. The first night out with it after modification I didn’t even pay attention to it slewing. Normally I always hear it even if I try to ignore it. But this time there just simply wasn’t really any noise to ignore. Yes, you can still hear the whirring but that will never go – that’s the motors. But as for that horrible graunchy noise? Completely a thing of the past.

And guidance? I was able to take a 3 minute exposure! That night was very limited – extremely almost – by cloud and poor seeing. But I’m more than happy with it. I’m incredibly excited to get out there again and finish dialling in my guidance, then I can finally justify getting narrowband filters!




“Should I do it?”

In conclusion I’m really happy I conducted this modification. The total cost was about £110, and whilst that might be expensive, just consider how long you’ll have the mount for. If you’re literally about to sell it- then no, don’t do the modification. But if you’re planning on having it still for several years? Then yes, I totally recommend replacing your gears for belts.

I have no doubt at all that the modification will make so much of a difference on my guidance, my images and overall performance of what is already a pretty solid mount.

Still on the fence? Well consider this: new HEQ5 Pros are now sold with this very belt modification already done to them. That’s the quality of this kit.

Speaking of quality and kit. The machining and finish of all the components is top notch. Honestly I almost think they’re undercharging for this modification! I reckon this is worth even £150. So for what they’re asking for the kit, postage and the pinion extractor. It’s great value for money.

And I’ve already addressed whether you should do it yourself or not. If you’re absolutely not confident in doing this modification yourself then give me a call, I’ll modify it for you! Ha.

With that last potentially serious or perhaps not statement, I wish you all a good day, clear skies and all the best fortunes upon you!

Bye bye!

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