Back in 2020, when I assembled my first serious astrophotography setup, one sentence from the community stuck with me – roughly: The mount is the foundation of your equipment. Buy the best you can afford. Your mount will see many telescopes come and go.
That statement has proven true. My HEQ5 Pro has since carried various optics: the Vixen ED80sf, the Takahashi FS-60CB, my son’s SkyWatcher Evo90 for solar observations, various camera lenses for different occasions – whether Perseid meteor showers, a lunar eclipse, or the Hyades. Today, it carries my standard setup: the Baader Travel Companion, a high-quality 4″ refractor, and the Vixen VC200L, which I greatly appreciate and use regularly.
During that same time, I’ve gone through my fourth and fifth cameras, transitioned from DSLR to mirrorless, and now use two cooled full-frame astro cameras. I also own a mono camera and work with high-quality narrowband filters. The HEQ5 handled all of this. It was absolutely the right call to follow that advice.
A Good Mount Fades Into the Background
The HEQ5 Pro is quite portable – no comparison to the bulky EQ6 derivatives. On typical nights at home, I achieved guiding performance around 0.6″-0.8″. Under truly dark skies in the Eifel region, values below 0.5″ were normal. For the image scale of my setups, that was solid and sufficient.
However, one thing kept bothering me over the years: backlash. Regularly – though manageable with routine adjustments – I had to tweak things.
After five and a half years, my HEQ5 has become my bottleneck. I won’t retire it permanently – but it’s time to take the next step and create a new foundation with more headroom.
The new mount needs to fade into the background and simply work. Always! – and represent a step forward in every aspect.
Nine Months of Research – (My) Little Pregnancy
I didn’t take this decision lightly. I spent around nine months researching, comparing, and asking questions.
My approach was intentionally different from typical forum browsing: I directly contacted astrophotographers on AstroBin whose images impressed me – and whose mounts I could identify in the metadata. My questions were structured: What RMS values do you achieve under which Bortle level? Would you buy it again today? What really annoys you?
Over nine months, this created a personal picture based on countless firsthand experiences—not a single spec sheet or manufacturer claim. A heartfelt thank you to everyone who took the time to respond. I also spoke with regional astro dealers, friends in my local astrophotography community, as well as bloggers and YouTubers.
The harmonic drive mount market is evolving.
What wasn’t even part of the discussion when I bought my HEQ5 Pro in 2020 is now a serious option for demanding mobile setups. That makes the selection more interesting – and more difficult. My thoughts were like a pigeon loft: some mounts came and went multiple times, others were ruled out surprisingly early.
How My Requirements Shifted
I started with the idea of building a truly portable setup for my Baader Travel Companion – lightweight, compact, travel-friendly. That was my starting point, looking at mounts with around 13 kg payload capacity.
Then came the question: What if I upgrade to a true high-end APO? A Takahashi 106, for example, weighs nearly 8 kg bare – fully equipped, a 13 kg mount would already be maxed out, making the investment pointless. My target shifted to around 15 kg capacity without counterweights.
Since I’m also interested in some 10″ telescopes, especially for lunar and planetary work, even that limit quickly became tight. Discovering direct drive technology paired with noticeably higher payload reserves ultimately shaped my decision.
The mount’s own weight became less important: my Baader APO setup weighs about 7.5 kg fully equipped. Suddenly, it no longer made sense to insist on a 3.4 kg mount while sacrificing so many options. A 5.7 kg mount is still much lighter than any of my telescopes and operates in a completely different league of portability compared to classic mounts.
The Starting Field
For completeness and fairness: none of the mounts I researched were described negatively by their current owners. The general picture was that most had found the right mount for themselves. All models listed here were serious candidates at some point.
ZWO AM5N (5.5 kg / 15 kg payload) – The best-selling harmonic mount on the market and my reference point throughout the research in terms of weight, payload, features, and guiding performance. However, its strong ecosystem integration wasn’t a plus for me – quite the opposite.
SkyWatcher Wave 150i (5.8 kg / 15 kg payload) – Briefly on the radar, but eliminated alongside the AM5N: I considered both functionally comparable, with no clear winner.
Pegasus NYX-88 (5.0 kg / 14 kg payload) – Interesting candidate, but it offered no real advantages over competitors that would justify a purchase.
Pegasus NYX-101 (6.0 kg / 20 kg payload) – The bigger sibling with significantly more payload. Still, no convincing advantage over the WD-20P – neither in drive concept nor ecosystem.
iOptron HAE29C-EC (3.7 kg / 13.5 kg payload) – Extremely lightweight and equipped with an RA encoder. However, no reserve for a potential Takahashi setup, and unsuitable for a 10″ telescope.
iOptron HAE43C-EC (5.7 kg / 20 kg payload) – A serious contender: reliable, good support, consistently good guiding values, and future-proof payload. Ultimately, it fell behind – mainly due to a fundamental consideration regarding the drive concept (more on that shortly).
Rainbow Astro RST-135E (3.4 kg / 13.5 kg payload) – Technically impressive and likely the best guiding performance in this group. It stayed in my thoughts for a long time. However, the price is hard to justify given the shrinking technological advantage and lack of updates since release. Also, 13.5 kg payload makes something like a Takahashi TOA borderline. My inner homo oeconomicus took over.
WarpAstron WD-20P (5.7 kg / 22 kg payload) – The decision. Why, I’ll explain next.
A Fundamental Question: Encoder or Direct Drive?
Harmonic drive mounts have a characteristic you need to understand: they exhibit noticeable periodic error. This originates from the strain wave gear itself and is inherent to all mounts of this design.
There are essentially two philosophies to deal with it:
One approach is encoders. An encoder on the RA axis measures the actual position and continuously corrects it. The practical advantage: the guiding camera can use longer exposures – 2, 3, or even 4 seconds instead of 0.5-1 second. This is especially valuable with off-axis guiders and narrowband filters.
The other approach is direct drive. Instead of correcting periodic error afterward, it is addressed at its root: a servo motor drives the gear directly – without belts, intermediate stages, or play. No belt wear, no aging, no additional transmission layer.
A dealer I trust summarized it perfectly: guiding constantly works against the encoder. The encoder corrects, the guiding corrects the correction – a cycle that never fully settles. With direct drive, this conflict layer doesn’t exist.
Coming from an HEQ5 with years of backlash issues, this logic immediately made sense to me: direct drive beats encoders. Not because encoders are bad – but because it’s more elegant to prevent the problem entirely.
That ruled out the HAE43C-EC despite its solid 20 kg capacity and good reputation – it uses belt drive like all iOptron harmonic mounts. The WD-20P does not.
Of course, encoders have their value – especially for unguided imaging beyond a few seconds. But that’s not my primary focus.
Why I Chose the WD-20P
Direct drive opened the door – but it took more than one advantage to justify the purchase.
Compared to the base WD-20, the “P” version features an improved RA motor – a concrete technical upgrade that sealed the deal. It also includes power and data ports directly in the saddle, simplifying cabling, reducing potential errors, and increasing flexibility.
OnStep – open, manufacturer-independent, compatible with INDI, NINA, PHD2, and virtually all other software. No dependencies, no limitations.
The 22 kg payload capacity gives me real freedom: high-end APOs, a 10″ reflector – no problem. While many competitors sit at the same limit, WarpAstron takes a clear step further.
Community reports consistently confirm guiding values between 0.3″ and 0.5″ under normal conditions. That’s the standard I want.
WarpAstron’s customer support is widely described as exceptional: fast response times, competent help, even via Discord. That builds trust.
More Than Just a Purchase
There’s one more aspect worth mentioning – even if it has nothing to do with specifications.
In December 2024, I made one of the most difficult decisions of my professional life: a significant job change that required courage and foresight. After a successful year in my new role, I want to reward myself – not with an impulsive purchase, but with something that will remind me, on every clear night for years to come, that taking the right step is worth it. What matters is conviction – comfort and fear are poor advisors.
The WD-20P is that reward. A true premium product.
Anticipation
The WD-20P is the logical choice: direct drive, open ecosystem, internal cable management, real payload reserves, and support I trust.
With it, my mount will fade into the background during night sessions and simply work – allowing me to focus 100% on astrophotography and enjoy it.
And it aligns perfectly with the foundation I laid in 2020: when I followed the advice of a valuable, helpful, and knowledgeable community and bought the best I was willing to invest in.
I’m really looking forward to getting my hands on the mount in the coming days and preparing it for our first clear night together. There’s still so much to discover in the night sky – I’ll report back.