ZWO AM5 - Experience and lessons learnt

[AstroGS]

I would like to share my personal experience from the ZWO AM5 mount which I am using now for over 4 months. What I've learnt from my time with it, the good parts, the ugly ones and why I will be keeping the mount. This is the genuine feedback from an amateur user and someone that is in this hobby for less than 3 years. I am sharing this for anyone who might have the mount and is trying to improve its performance or someone that is considering to invest in this mount.

 

But, before I proceed with the details, I would like to share that I was a proud owner of SW AZ-EQ5, then a EQ6R-Pro, AZ-GTi and a Sky Adventurer. From my time with these mounts, I must say that the AZ-GTi was my favourite not only because it was super portable but, also because it did track well - actually very well! On the other hand, the EQ6R-Pro was very good, consistently tracking between 0.6-0.8, even close to 8kgr of payload. But, it is heavy and is not friendly for quick setups. You see, I do not have a permanent observatory and the setup was taking 20-30 mins each time, including balancing, PA and etc. If it was a Friday or weekend, then that was not an issue but, if it was during the working week then it was almost a no-go since I would be busy or tired from work.

 

I would use the EQ6R-Pro while imaging at home and the AZ-GTi when on a trip and thus, I had to maintain 2 mounts with the compromises that each mount had. So, I started investigating the possibility to have one mount which, could be used for "serious" imaging while at home but, it would be very portable and could join us while we were on a trip.

 

The tech that ticked all the boxes (light weight, payload capability and tracking accuracy) was Rainbow's Harmonic mount the RST-135. Unfortunately the price tag was very dear for me and thus, I couldn't afford it but, there were some other mounts at that time that started appearing in the market. The 3 mounts that were shortlisted: iOptron HEM27, Pegasus NYX101 and ZWO's AM5. The Pegasus was still not launched and I was not sure if it will be supported by AsiAir, iOptron's HEM27 was using a hybrid harmonic approach for the DEC/RA axis, while at that time ZWO AM5 was getting track with multiple YT videos and positive input from different users. So, I decided to bite the bullet and ordered the AM5, with the relevant extension pier and the TC40 tripod. But, in order to fund the new mount I had to sell the EQ6R-Pro, the AZ-GTi and the Sky Adventurer --> so, I was left with only 1 mount!

 

When the AM5 arrived I was very impressed with the build quality and how much less it weighted compared to the EQ6R. My first impressions were followed by a couple of positive-first-light evenings. Setting it up is very simple, as you can keep the whole rig on the mount/ tripod and just lift it to take it out. From the moment you decide to start imaging, until you will start imaging is now down to 5-10 mins. Huge difference of what I experienced till now.

 

But!

 

Unfortunately, after a couple of sessions the AM5 started behaving weird and it couldn't maintain a consistent level of tracking. There were nights that it would start from 0.8-0.9 and during the same 600-sec sub it would increase to 1.8-1.9 and then go back to 0.9-1.0. This would repeat 2-3 times during the same sub. I am talking about evenings with no clouds, no moon and no wind at all.....

 

With the support from FLO (thank you Alex), i performed quite a few tests and gathered data from logs over a period of a few evenings to finally, agree that it needs to be returned. At that point I genuinely started considering to swap it and go back to the trusted EQ6R-Pro. But, there were so many people raving about this mount that, I thought it might have been just a bad example of the mount. So, I decided to swap it with a new AM5.

 

I have now the new mount for over 3 months and it is working perfectly - I hope that I did not jinx it - and I used it for over 10 times. I have used this mount with both of my OTAs (Redcat51 and Stellamira ED90 Triplet).

 

To perform well and consistently, the mount requires the following:

 

A good and stable tripod

The TC40 is light-weighted and super portable. It holds the AM5 very well and securely (good job AM5) but, in my humble opinion it is not for long exposures. Every single breeze of air will be transferred to your sub - especially if the payload is really light. I have tried the tripod with the rubber feet and the spikes, on Celestron's anti-vibration pads and/ or with 10 kgs of weight in the bag with no noticeable differences in it performance. The tracking with the TC40 was always around 0.9-1.1 total RMS error.

So, I decided to buy a SW 1.75inch tripod along with ZWO's PE200 pier extension. It fitted perfectly and even in the very first evening the performance of the tracking improved, achieving a consistent 0.7-0.9 throughout the whole session. This was the case for almost every session after.

Then, just a few weeks ago, a Barleback Planet came in the 2nd hand market with an HEQ5 adapter at a reasonable price and thus, I bought it. Unfortunately the PE200, wouldn't fit perfectly in so, I had to trim and treat the adaptor so it will take the PE200 extension pier. It wasn't that difficult and eventually the pier fitted perfectly.

This changed completely my experience with the mount - the tracking improved significantly and now it is achieving 0.4-0.5, with peaks of around 0.6. Even after dithering, it takes only 3-5 secs to settle and get back to 0.4-0.45! I have never experienced something similar with any mount.

Attaching some pics from my last session.

 

Conclusion: The AM5 is heavily relying on a good and stable tripod, to deliver a good performance.

 

PA is super important 

Take your time while polar aligning your AM5. I am only using the AsiAir+ for PA. Εvery single time that I was not on less than 10" of error, I would experience at least 0.1-0.2 more total RMS error in my guiding. The AM5 has super simple and easy-to-use knobs. Take your time and try to get the PA less than 10". You will be rewarded at the end. 

Also, something else that I found out was that, performing the PA process twice improves the stability/ consistency of the tracking. I am not sure if it is the AsiAir's issue or the mount's but, performing the PA process twice has worked for me - every single night! What are your thoughts?

 

Conclusion: Take your time for the PA (if you are using AsiAir like me) and even do it twice.

 

Tracking settings -My routine is as follows

Immediately after the PA is completed (and while the mount is still rotated at 60 degrees), I choose a point close to the celestial equator and the same side that my target is.

The mount slews at that point and before I start the calibration process, I make sure that the guide scope is very well focused. 

Also, make sure that the FL for the guidescope is correct - I have done that mistake in the past a few times. My camera is an ASI290mm mini and I usually use a gain of 200-250.

Calibration settings (using the AsiAir):

• Exposure time: 2 secs
• Aggression: 50% for both DEC/ RA
• Calibration Step/ Max RA and DEC duration: All 3 at the default value of 2000
• Auto Restore Calibration: Off

After it finishes the calibration process and it settles, I slew from there to the target for the night.

 

During the evening, I might need to increase/ decrease the aggression based on the correction points. If there are too many on one side, then usually increasing the aggression  smooths the graph out - if the corrections are increasing/ decreasing continuously then the aggression needs to be lowered. 

More about on how to improve guiding with AsiAir: https://eastwindastro.blogspot.com/2021/02/how-to-adjust-asiair-guide-aggression.html?fbclid=IwAR3c4SkPY_K6mfO8RUY9QduzHyDiBBXBCussh05oQgjqQREPdCBgCeyPzU4

 

I do hope you find this interesting and I hope it helps.

 

By the way I am not a pro in writing similar posts!

 

 

 

 

Edited January 9, 2023 by George Sinanis

[Elp]

Nice write up. I am in in similar position but content with what I have at the moment, having a C6 although the azgti can "do it", guiding does struggle even though it's weight is similar to my refractor setup. So I need beefier kit for the C6 which adds to the setup and strip down every session routine which does irk over time. The am5 (also best price, other HD mounts may also achieve the same thing at higher price) seems ideal as I can keep it within the same bag as the scope so one less hassle when setting up, it's one of the reasons I use the azgti the most for convenience. 

I always recommend to people when starting out to consider tripod+mount, and always make that distinction between the two that most people fail to. They are two different things, a poor tripod will mess everything up even though the mount head might be good. Glad you happened upon a berlebach and were fortunate enough to acquire it. I have a uni, and would recommend it to everyone (payload permitting), tripod makers should take note of how good they are, I often break it out when it's slightly breezy, it makes such a difference. Other similar tripods likely will do the same also.

One thing I've noted about the asiair since it's most recent update, they've dialled back the PA accuracy. I was always able to get it within 20 arc seconds, now it's a bit of a struggle to get it below one arc minute let alone closer to zero as before. But yes, I've always strived to get under one arc minute (it obviously depends on your pixel imaging scale what you need) as it makes a lot of difference.

Edited January 8, 2023 by Elp

[Martthebass]

Thanks for the write up, very informative.  I came from an AZEQ5 to the AM5; I always struggled to get good balance on set up (same 90mm scope as yourself) and it meant that I spent more time out in the cold than I liked.  I wanted a one lift out and due to a current health problem I also went the TEC40/PE160 route so I could do this without undue grunting.

I've generally found my RMS error to be about 0.6" with the odd excursion to 0.8" which is more than adequate on 300s subs at my focal length.  Sometimes, when seeing is better than average this comes down to 0.4" or a bit lower (all on 1sec guide exposures).  I've not done much research into the effects of good PA, I generally make sure it is <1' (normally <30") and check after I've locked off the mount and generally always get the figures above.  I've not had the setup out in 'big wind' but it wouldn't surprise me if the mount was a bit susceptible to the odd gust.  

Regarding calibration; I used to do this every time with the AZEQ5, with the AM5 I've generally found I only 'need' to do it every 4 or 5 sessions, not sure why that is the case but it does seem to be fairly consistent from session to session.

Overall, like you I think it's been a positive experience so far, the only negative experience so far was when the mount inverted the scope into the tripod when sent to home at the end of a session....never found the reason for that and concluded it was an ASIAir glitch (it did manage to do this with my AZEQ5 once) - fortunately it hasn't happened since. 

 

[StevieDvd]

How did you trim the SW adaptor for the PE200 to fit the HEQ5 adapter, did it need much taken off?

I was considering my options of having a pier adapter for a HEQ5 bored out a little if I could find a local lathe machinist. Or simply attaching the adapter to a power drill and running a file over it to reduce its diameter.

Steve

 

 

[AstroGS]

1 hour ago, StevieDvd said:

How did you trim the SW adaptor for the PE200 to fit the HEQ5 adapter, did it need much taken off?

I was considering my options of having a pier adapter for a HEQ5 bored out a little if I could find a local lathe machinist. Or simply attaching the adapter to a power drill and running a file over it to reduce its diameter.

Steve

 

 

Hi Steve,

I will take a few pics next time I get the chance. It wasn’t too much… I would say 1-2mm max.

[StevieDvd]

12 minutes ago, George Sinanis said:

Hi Steve,

I will take a few pics next time I get the chance. It wasn’t too much… I would say 1-2mm max.

Thanks,

Pictures not really necessary, just wanted to know if you used a method (successfully) that I have considered using.

[Stardust1]

Excellent write up! 

Do you level the tripod when polar aligning?

 

 

 

 

[AstroGS]

6 hours ago, Stardust1 said:

Excellent write up! 

Do you level the tripod when polar aligning?

 

 

 

 

Although a lot of people say that tripod levelling is not necessary since you PA, my opinion is that levelling the tripod not only offers much better stability but, also supports better your imaging rig. Especially in fast changes in direction, e.g. meridian flip.

Finally, I believe that levelling the tripod should be the very least time consuming process amongst the others you need to do to start imaging so, why not anyway. 

[StevieDvd]

There is a good reason for levelling the tripod when using a software based PA, such as the ZWO PA routine.

When the PA app tells you to adjust up/down or left/right if the mount is level then the adjustment is a little easier.

With a badly levelled mount any adjustment in one axis probably needs a compensating adjustment in the other.

Edit

The levelling discussion is a little off topic  - except in relation to using the ZWO system  - so best left off this thread now.

 

Edited January 10, 2023 by StevieDvd

[The Admiral]

I prefer to use a spirit level across the top of the tripod for levelling, as I don't find the built-in bubbles to be very sensitive.

Ian

[Stardust1]

I was informed that levelling the tripod was not necessary. But it makes it easier to polar align once the tripod is leveled.

[Elp]

It's not necessary, but I believe in learning and teaching good practice, so if it only takes a few seconds to check, why not do it, it also better balances your load on top of your tripod evenly between the legs. If you decide to switch to alt az, you'll be glad you had put it into practice to make it second nature.

[AstroGS]

Here is a very interesting read from ZWO's website on how to (systematically) improve guiding with the AM5. Ya Ge seems to have gone to a thorough analysis of how to improve guiding which I read myself carefully before trying to improve the guiding on my AM5. I did not follow all the suggested steps from Ya Ge but, overall since it is part of the AM5 mount and guiding, I thought it will be good read for others as well.

https://astronomy-imaging-camera.com/news/systematically-improving-guiding-quality-and-zwo-am5-mount-review.html

[AstroGS]

Another night - imaging IC417 - with wind reaching 20mph and wind gusts up to 36 mph.The tripod is what makes the difference tonight. Apart from a few moments that the wind was strong - and spiked the error to 1.2 - it is holding around 0.6-0.7.

Imaging with the Redcat51 and the "small" WO Uniguide 32/120mm, this means 1sec exposures and 30% aggressiveness on both DEC/RA.

DEC/RA/STEP points still at 2000 all 3.

Edited January 12, 2023 by George Sinanis

[Elp]

Brave, I don't bother if wind is higher than 10.

[AstroGS]

6 hours ago, Elp said:

Brave, I don't bother if wind is higher than 10.

Me neither tbh but, skies are rarely clear nowadays and I did want to test how it would behave.

 

Today however is a completely different story. Even the PA process was a challenge with the AsiAir+ today. It took more than 15 secs to plate solve each image during the process!! I had to increase exp time to make it work.

 

Guiding is not good today due to poor seeing and the wind is picking up by the hour - the tracking figures vary from 0.6" to 1" during each sub. As I am using the Redcat51/ 2600MC combination, the subs look ok/good for now.

 

 

[AstroGS]

And here is the image from the last 2 sessions (approx. 8 hrs) - not bad for a windy and poor seeing couple of evenings.

 

[skyrunner]

On 09/01/2023 at 18:09, George Sinanis said:

Hi Steve,

I will take a few pics next time I get the chance. It wasn’t too much… I would say 1-2mm max.

I'm thinking of getting an AM5 but I'd like to use it with my Berlebach.  Just to be clear, you needed to reduce the diameter of the PE200 SW adapter (not modify the Berlebach) to make it fit onto the Berlebach HEQ mount.

Gordon 

[AstroGS]

13 minutes ago, skyrunner said:

I'm thinking of getting an AM5 but I'd like to use it with my Berlebach.  Just to be clear, you needed to reduce the diameter of the PE200 SW adapter (not modify the Berlebach) to make it fit onto the Berlebach HEQ mount.

Gordon 

Hi Gordon,

It is the opposite I am afraid - I did widen the BB Planet's adaptor circumference by almost 1mm. I did not want to alter the PE200 as I will be using it with other tripods when I am in the field.

Here is a pic from the last session - just as FYI

Edited January 15, 2023 by George Sinanis

[skyrunner]

8 minutes ago, George Sinanis said:

Hi Gordon,

It is the opposite I am afraid - I did widen the BB Planet's adaptor circumference by almost 1mm. I did not want to alter the PE200 as I will be using it with other tripods when I am in the field.

Thanks, George, that's helpful to understand. 

Gordon 

[jpoulette]

On 10/01/2023 at 05:36, The Admiral said:

I prefer to use a spirit level across the top of the tripod for levelling, as I don't find the built-in bubbles to be very sensitive.

Ian

I use a simple alt-az and I still like to keep it as level as I can with a spirit level. It makes sense and it's not that hard really.

My dad was a hardwood cabinet & furniture maker (in his retirement) and he was always obsessed with "level & plumb".

One of the good attributes I inherited ! 😀

Jim

Edited January 19, 2023 by jpoulette

[Elp]

@George Sinanis I had a few queries and checked with ZWO, the am5 only has a brake on the RA and not the DEC in case of a power loss. In your experience is this an issue?

[AstroGS]

24 minutes ago, Elp said:

@George Sinanis I had a few queries and checked with ZWO, the am5 only has a brake on the RA and not the DEC in case of a power loss. In your experience is this an issue?

Apart from once that the power cable was pulled from the Pegasus power box while I had my Redcat on, I never experienced a power loss while using the heavier Stellamira. 
 

But this is not something that would worry me to be honest. 

[StevieDvd]

1 hour ago, Elp said:

@George Sinanis I had a few queries and checked with ZWO, the am5 only has a brake on the RA and not the DEC in case of a power loss. In your experience is this an issue?

I was interested in the details of the Rainbow RST-135 as a comparison to my AM5 and came across the youtube video of what happens in the event of a power loss to these mounts - referred to as backdriving.  The video shows several examples of a heavily loaded mount going into an uncontrolled spin. It was interesting to see him put his full image train at risk to demonstrate the lack of a brake and the impact was quickly stopped on any power restoration or simple manual intervention. Even when he allowed it to crash the impact was so slight the sponge around the tripod leg was sufficient to bring it to a halt.

So the AM5 only having the RA brake is not such a negative on this kind of mount.

 

 

[AstroGS]

21 hours ago, StevieDvd said:

I was interested in the details of the Rainbow RST-135 as a comparison to my AM5 and came across the youtube video of what happens in the event of a power loss to these mounts - referred to as backdriving.  The video shows several examples of a heavily loaded mount going into an uncontrolled spin. It was interesting to see him put his full image train at risk to demonstrate the lack of a brake and the impact was quickly stopped on any power restoration or simple manual intervention. Even when he allowed it to crash the impact was so slight the sponge around the tripod leg was sufficient to bring it to a halt.

So the AM5 only having the RA brake is not such a negative on this kind of mount.

 

 

Nice video and it demonstrates the risk with this type of mounts. Nevertheless, this is a 12-13kgr rig (including camera, reducer, guidescope and etc.), which in my opinion is not the right mount for regular use with this type of OTAs. 

 

I would probably use it in specific occasions (e.g. a star party where I want to get my larger FL OTA) and at the same time I do not want to carry a heavier mount (e.g. EQ6R Pro) but, definitely this is not the right mount for me to use with such heavy ota’s on a regular basis. Why am I saying this? Because in those situations where I would want to use my larger FL and heavier OTA, I would always use the counterweight even if the manufacturer is “confident” about their mount’ specs. I wouldn’t mess with physics laws and especially when I have a £6K rig on it 😉

 

I am also starting to read that ZWO will start suggesting counterweights for over 10kg, moving forward for the AM5. My heaviest rig till now is the Stellamira ED90 triplet, which weighs 7kg, if I remember well, with everything on it; my concern here though is not the weight but, the length. It is over [edited] 0.7m in length. Next time I get this ota in use, I will perform some tests and see how the mount behaves.

Edited February 15, 2023 by George Sinanis