Stability in AM5 - Forums

Hello all,

I’m planning to buy something with more focal length and can already say that it will be either the Askar 120 or the 103. I’m only owning an AM5 on the ZWO TC40 tripod and have no plans on upgrading it.

Does someone have any experience regarding this setup in terms of stability? I have worries that especially the 120 APO could be too exposed to strong wind due to its length of almost 1m (?) with extracted focuser, camera, EFW etc. attached. Unfortunately, I have never used a scope of this length before, so my own experience on that topic equals zero.

I hope you can help me a little bit :)

Clear skies, Louis

Hi Louis,

I have an Askar 120 APO and I mount it on an AM5 with the TC40 carbon fiber tripod. Guiding is typically around 0.50” with winds of, say 6 mph or less. I try to avoid imaging with winds much above 12 mph and would expect to see the guiding numbers run higher under such conditions.

The first thing is that you will need a pier extension to use the Askar 120 on the AM5/TC40. I think the one I have is “ZWO 200 mm Pier Extension for AM5 Mount”. Without a pier extension I would expect to hit the tripod legs when pointing at/near zenith.

Also I use weights in the tripod weight bag. The picture below shows several 5 pound dumbbell weights in the bag (and my battery on the ground). Currently I use a pair of 10 pound free weights to help keep it stable. I’m quite happy with it!

Here is my setup…

📷 IMG_0437.jpeg

I second the weights. Without them the rig could blow over if you get a strong wind gust. I’ve seen that happen with heavier mounts then this.

Michael Cory · Dec 18, 2025, 10:49 PM
Hi Louis,
I have an Askar 120 APO and I mount it on an AM5 with the TC40 carbon fiber tripod. Guiding is typically around 0.50” with winds of, say 6 mph or less. I try to avoid imaging with winds much above 12 mph and would expect to see the guiding numbers run higher under such conditions.
The first thing is that you will need a pier extension to use the Askar 120 on the AM5/TC40. I think the one I have is “ZWO 200 mm Pier Extension for AM5 Mount”. Without a pier extension I would expect to hit the tripod legs when pointing at/near zenith.
Also I use weights in the tripod weight bag. The picture below shows several 5 pound dumbbell weights in the bag (and my battery on the ground). Currently I use a pair of 10 pound free weights to help keep it stable. I’m quite happy with it!
Here is my setup…
📷 IMG_0437.jpeg

Great set-up! I use my old Sky-Watcher HEQ5 tripod with a weight/stones bag with the same pier extension. It has been very reliable.

I ran the Askar 120APO on the Emcan EM31 Pro mount (exactly the same weight class mount as the AM5). I did use a counterweight as I felt more safe, and you will 100% need the 200mm pier or the scope will hit the tripod legs.. Even with the pier, if you’re shooting mono, I would recommend rotating the camera so that the filterwheel is pointing ‘upwards’ away from the tripod. This will give you a little more safety around meridian limits.

As far as tracking/stability - Never had an issue.. Using an OAG I routinely guided at 0.3~0.6” RMS

Thank you so much for your advices!

This really helps me. I think the consensus in all your comments is that it makes sense to use counterweights for more stability (either in the usual way on a counterweight bar and/or in the tripod bag).

Luckily, I already have the bar for the AM5 and some counterweights of different sizes. The point is that I want to keep my setup overall as lightweight as possible as I’m running my setup mobile.

Do you think the situation would change at all when using the smaller 103APO? There’s only 1kg difference to the 120APO… Rather on I could imagine going without the counterweight bar and only putting my Battery (ca. 3kg) and maybe a 2kg counterweight in the tripod bag.

Hi Louis,

From what others have said, It looks like the AM5 will be a great match with either scope. I have the AM5 with the carbon fibre tripod and love it. That’s with a 102mm refractor and full mono imaging train.

You’ll definitely need the pier extension. The PE200 has a higher weight rating than the one with three columns. I also hang a 5 kg dumbbell off the central knob underneath so it partly sits on the ground, for more stability. I also have the scope sitting on risers off the plate for added clearance as the EAF would sometimes still clip the tripod and rotate the camera. With the scope now further from the centre, I’ve felt more comfortable with a counterweight. All well within the limits of the mount.

I think a weighted base will do just as well for you as a counterweight but that’s something you can test by extending the scope and giving it a nudge. Would you be happy with the stability it shows if a gust of wind came along?

Where I’m living now is quite windy so at home I try to shelter the scope with outdoor furniture on the balcony or my car parked beside the scope in the driveway.

I feel the weakest link in these setups is the tripod, not the mount. In the last week, I’ve upgraded the tripod to something high end which is a beast but not as easily managed. With the Zwo tripod, I could flick the image train and it would vibrate like a guitar string. With the new tripod, it doesn’t budge at all.

That might be something to consider down the track. The standard setup has served me very well for a few years as it should for you.

Glenn Baxter · Dec 19, 2025 at 10:57 AM
Hi Louis,
From what others have said, It looks like the AM5 will be a great match with either scope. I have the AM5 with the carbon fibre tripod and love it. That’s with a 102mm refractor and full mono imaging train.
You’ll definitely need the pier extension. The PE200 has a higher weight rating than the one with three columns. I also hang a 5 kg dumbbell off the central knob underneath so it partly sits on the ground, for more stability. I also have the scope sitting on risers off the plate for added clearance as the EAF would sometimes still clip the tripod and rotate the camera. With the scope now further from the centre, I’ve felt more comfortable with a counterweight. All well within the limits of the mount.
I think a weighted base will do just as well for you as a counterweight but that’s something you can test by extending the scope and giving it a nudge. Would you be happy with the stability it shows if a gust of wind came along?
Where I’m living now is quite windy so at home I try to shelter the scope with outdoor furniture on the balcony or my car parked beside the scope in the driveway.
I feel the weakest link in these setups is the tripod, not the mount. In the last week, I’ve upgraded the tripod to something high end which is a beast but not as easily managed. With the Zwo tripod, I could flick the image train and it would vibrate like a guitar string. With the new tripod, it doesn’t budge at all.
That might be something to consider down the track. The standard setup has served me very well for a few years as it should for you.

Hi Glenn,

with my current setup (focal lengths at 450 mm and 330 mm with a much shorter scope) I have never had any issues with wind wich is typical for my region.

The best case would be that I would make the same experience with one of the scopes either in the future regarding wind and its influence on the guiding accuracy.

Tony Gondola · Dec 18, 2025, 10:56 PM
I second the weights. Without them the rig could blow over if you get a strong wind gust. I’ve seen that happen with heavier mounts then this.

I use a couple of cheap 1kg weights from Decathlon (tie wrapped together). https://www.decathlon.co.uk/p/weight-training-1-kg-28-mm-partly-recycled-cast-iron-plate/348950/m8816722

Does the job.

Never had a problem with my 125mm StellaMira rig.

You could probably fit a couple of 2kg weights if you wanted to be uber cautious…

Having said that, I don’t really go out with my larger rigs in gusty conditions.

Louis · Dec 18, 2025, 07:07 PM
Does someone have any experience regarding this setup in terms of stability? I have worries that especially the 120 APO

Hello

I have a strain wave mount (not Zwo) which is a bit touchy to use with my fully fledged TSA120. I is acceptable if :

no wind
serious balancing about DEC axis (feasible on a table but rolling the lower dovetail and marking the position of the center of mass)
serious balancing about RA axis, by computation of the right distance to place the counter weight
maybe (or certainly ! ) invest in an oversized tripod. The lack of load balancing generates torques on the tripod head and may ruin stability.

Louis · Dec 19, 2025, 07:09 AM
Do you think the situation would change at all when using the smaller 103APO? There’s only 1kg difference to the 120APO… Rather on I could imagine going without the counterweight bar and only putting my Battery (ca. 3kg) and maybe a 2kg counterweight in the tripod bag.

Hi Louis,

I’m operating a setup with the 103APO and AM3 (OSC without a filter wheel). I’ve done as you are asking when I travel with my setup; leaving the counterweight bar and placing the battery & counterweight in the tripod bag, and it has worked well for me. My guiding is still good in that situation and the setup feels solid, although I wouldn’t do that on a more windy night. I’ve come to prefer bringing & using the counterweight bar more for my own peace of mind. If you were to go with the 103APO, I think it would be reasonable to leave out the counterweight bar and put the battery in the tripod bag.

Caleb

I use the Skywatcher Wave 150i, its the same class of mount as the AM5. With the carbon tripod it works ok with no wind. Otherwise it's not great, too flimsy.

I use now a steel eq6r tripod, good investment, its super stable (tripod weighs 7.5kg) even when there is wind. No counterweight needed imo.

Looks like fun ! I am using am5 with my new 8” edge I upgraded the tripod to an avx tripod fits perfect and got an 11lb counter weight solid as can be. .3 arc sec guiding consistent with oag.

Hi, Louis.

I’m not sure you need any more info, but thought I might chip in anyway as you never know what helps.

I have the AM5N and TC40 carbon tripod, but now only use my EQ6 tripod as I found the TC40 a little too flexy for my taste (even with weights in the bag). I bought the AM5N because I was tired of lugging my EQ6R mount around the countryside, so the EQ6 tripod was already in hand. (Note. THe EQ6R mount is brilliant and if I had a permanent setup, that’s what I’d use).

I use an EdgeHD8 and a Skywatcher 120ED on it, shooting mono. As Alex suggested, you’ll definitely need the extension if shooting mono and I found I was still at risk of hitting the tripod legs if not careful. So now I have the ZWO 200mm pier extension on top of the EQ6 extension. It might seem like overkill but I leave them bolted together and consider it just one large extension atop the EQ6 tripod; everything I put on top is now well clear of the tripod legs.

The AM5N is such a delight to use (plus carrying it about and lifting onto a tripod compared to the EQ6R) and the setup with the EQ6 tripod and extension combo is rock solid.

Cheers.

Paul

Thank you everyone for your advices :)

I think I’ll stay with current lightweight and "semi-windproof” setup until I got a beefier tripod (and mount). But I’m sure this thread will help other users who have the same plans as I did on the beginning of this thread.

CS, Louis

Paul Larkin · Jan 3, 2026 at 02:00 AM
Hi, Louis.
I’m not sure you need any more info, but thought I might chip in anyway as you never know what helps.
I have the AM5N and TC40 carbon tripod, but now only use my EQ6 tripod as I found the TC40 a little too flexy for my taste (even with weights in the bag). I bought the AM5N because I was tired of lugging my EQ6R mount around the countryside, so the EQ6 tripod was already in hand. (Note. THe EQ6R mount is brilliant and if I had a permanent setup, that’s what I’d use).
I use an EdgeHD8 and a Skywatcher 120ED on it, shooting mono. As Alex suggested, you’ll definitely need the extension if shooting mono and I found I was still at risk of hitting the tripod legs if not careful. So now I have the ZWO 200mm pier extension on top of the EQ6 extension. It might seem like overkill but I leave them bolted together and consider it just one large extension atop the EQ6 tripod; everything I put on top is now well clear of the tripod legs.
The AM5N is such a delight to use (plus carrying it about and lifting onto a tripod compared to the EQ6R) and the setup with the EQ6 tripod and extension combo is rock solid.
Cheers.
Paul

Hello Paul

I get an AM5 (not N) and would like to know if your guiding is ok with EdgeHD8 ? ( i presume you dont use hyperstar…). and what about with your 120ED ?

because i heard about doubts for long focal shooting and guiding with AM5 ( not regular mechanical driving due to this tecnology)

Thanks

Clear sky for you in Australia ? here south france is a disaster for mre than 1 month…

Hi, yfficroma.

I looked back over some of my data to check to be sure I could present data rather than guesses from memory.

With my C8 I typically get around 0.7” (with an OAG) averaged over my 5 minute subs. This is mainly from by suburban back yard, where the surrounding air can still be warm and a little turbulent from the day (and sometimes a bit windy). On a good night, away from town, I can get to 0.4-0.5”.

Away from town, my 120ED (also with OAG) is generally 0.4”-0.5” but I sometimes get as low as 0.3” (which Michele says he gets too).

When the seeing (or wind) is bad, both can get up to around 1.5”.

Thanks for the wish of clear skies. 2025 has been more cloud than I can remember and right now (summer), still cloudy and also warm. I had about 1/3 as many shooting nights as 2023 and 2024. But still, always plenty to learn!

All the best.

Paul

Hi Paul

Thanks for answer. So AM5 and C8 fit together. very good news (0.5” is excellent) . Now i watch for your pictures to enjoy, and project to invest for deep sky pictures with a C8 ( no edge) on my AM5. I get OAG and 30mm guide telescope.

have a great clear sky in your summer.

all the best too

Yves ,south France

Quote

Does someone have any experience regarding this setup in terms of stability?

Unquote

Hello

I have used a few days ago something similar :

Nyx101
With counterweight bar
No weight on the bar
Sw esprit 100
Eq6 tripod with home brew extension

Results were good in terms off guiding accuracy.

With my TSA 120 I think fine DEC balance and AD compensation as a minimum are mandatory.

With a proper balanced RC8 it is still ok as long as the seing is good, thanks to reduced inertia since the tube is short.

I havd tried with a 150mm triplet : no way, full stop.

Nice set up , bravo

with C8, what do yu mean “as long as the seing is good” ?

thanks

yves

That's a bit out of scope, but as the seing degrades I generally have poor guiding and thus high rms which blurrs star images.

So its merely a seing issue. I didn't invest sufficient parameters tuning to improve the results, so I can't blame harmonic systems for that.

yeap Alpheratz 06

, so many parameters are involved !

Sky quality is the first “guilty” from my experience, yours too

(shoot at 2000m high without clouds is a nice experience for getting good signal, i had the chance to make it last summer)

your harmonic mount is for sure one of of the best in the class so….no matter.

thanks for exchange.

yves

A last word about balancing : it’s a straightforward operation on a classical GEM with brakes on axes.

For an strain wave mount, it’s a bit more tricky.

Here is my recipe, always IMHO :

For DEC axis , two possibility to determine the longitudinal position of gear CoG : (i) use an auxiliary mount with an horizontal axis to measure CoG position and register it with respect to the centre of the clamp (ii) simpler : use a cylinder-shaped object , diameter 15-30mm diameter, put under and across the bottom dovetail on a flat and horizontal surface ; gently roll the gear forth and backward, find the balance point and mark it on the dovetail, and use the marked position centred on the mount clamp. Whatever you load, please (at least roughly) tune DEC balance
for RA axis, the only practical solution I have found is by computation : I weight all the components (optics, camera, hardware, CWbar… etc but the cables ) and I measure the distance of each component with respect to the RA axis. Then , it’s easy with any spreadsheet to compute mass and position of the CW to achieve balance. For the sake of mechanical limit, I limit myself to a total counterweight mass of 7,5 kg on the bar, to limit torque on the bottom box of the mount.

This definitely (I made some tests ) improve guiding accuracy by limiting error excursion.

RA balance tuning is needless for loads under let’s say 8-10 kg… the CW bar is enough in such cases.

Remember that the issue in RA is also a matter of inertia unbalance as well as weight itself : that’s why “small” harmonic mounts do not handle refractors above 120mm . I suspect that inertia unbalance generates dynamic torques and thus dynamic cross-coupling between RA and DEC: the lack of stiffness of lightweight mounts ( you cannot get light mass and stiffness together) makes them prone to such behaviour.

That being say in my talkative way, these small mounts are wonderful toys to operate a wide range of instruments in full mobility. Should I keep only one mount, I still would go for HM.

Thanks for this complete answer. but IMHA ? can you explain please ?

yves

Sorry , I made a typing error. IMHO, for “in my humble opinion”