Yet another AM5 guiding thread
As Chen said it has lots of high harmonics but a lot of the 288s period mounts have these rough curves and some guide well. So it seems in Asiair. You may get a worse mount the second time around if you order a replacement. Your mount has small PE but it is not smooth wheras higher end mounts have larger PE but smooth sinusoidal curves. I have found that with a rough high harmonic mount curve that these amateur mounts have, a lot of guiding advice does not work as well as with a smooth curve. In fact I can alter my durations and aggressions a lot and it changes nothing some nights. I am constantly testing and one definitive thing I have found is… asiair while convenient, is not good enough to tame a bad mount. You can give it all you have and nothing seems to control it when using asiair. Just make sure your Minmo is around no higher than 0.1px and disable backlash compensation unless it is really necessary.
w7ay Kevin_A thanks for your feedback and advice…as this is my portable mount I’m not obsessing too much about guide errors just trying to get the best results possible as mentioned earlier. My iOptron CEM70 performs consistently at sub .4 arcsec rms. Unfortunately it weighs a ton 
Out of curiously, 2hat would you consider to be a higher end strain wave mount?
w7ay they really are just amateur mounts as they are very coarse in function! And the asiair implimentation of phd2 does not help. I upgraded all my guide scopes and it did only a little to help. When having perfect PA helps more than sharp stars one knows it is best to change ecosystems if you want the best and excellent images. For me right now I am ok with 0.5 to 0.6rms guiding averages as my biggest scope is a 644mm and I do not need 0.3rms guiding to get good round stars. But when I get around to building a skyshed with a bigger scope it will be with a premium mount and not Asiair controlling it! I will use the asiair ecosystem then on my AM5 when I go to the lake to do 15mm milkyway shots with this forgiving guided rig.
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Kevin_A I don’t own an Asiair and been only using phd2 so far. I just installed Metaguide which in theory could produce better guiding results since it’s using the camera’s video feed with a clever centroid averaging algorithm to track rather than discrete exposures. I have a feeling this type of guiding might be better suited for mounts with higher rates of change in their PE curve based on everything you experienced and w7ay has mathematically demonstrated on other threads.
Kevin_A I assume by premium mount you’d be looking at a more traditional worm
Gear mount? I haven’t done much research but at least what’s available here in Canada in terms of pure strain wave drive mounts seems to be the AM series from ZWO or the RST series from rainbow Astro. The RSTs are significantly more expensive the AM but I guess based on what w7ay explained on other posts, they seem to be better made and might have a better gearbox(?)
Again for me, the AM5 is the portable rig which I’m using with my portable refractor setup. My 10” fast newt lives on the CEM70 and I have had no issues with guiding at all with this combo.
It’s just always good to understand the equipment and try and squeeze as much performance as possible given the use case and price point.
Kevin_A Seriously? Haha It is like taking a dump truck to the racetrack or a Corvette off-roading!
So far, the largest payload I have put on the RST-135 and RST-135E is the FSQ-85 (dual saddle with side-by-side guide scope adding some 5 or 6 lbs).
I have received my Mewlon 180C (waited a year for Tak ' manufacturing run) and will try that as a payload. But that is the absolute max I will put on it when weather allows. I have in the past without trouble used a C6A on an RST-135. The strain wave gear should have no problem slewing the Mewlon (even C11), but guiding could be a problem, we'll see. That being said, I plan on using the Mewlon unguided on the RST-135E, though -- the OTA is just for planetary (the encoder will keep the planet inside a 2.5" FOV).
Hope I don't have to go to an RST-300 (way heavy for my taste, and I w'll need them to release an "E" version, in any case).
Chen
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eyecon I too am in Canada, near London Ontario. I have had worm gear mounts and I just got fed up with the huge weight carrying it and then balancing it. I would be looking at a RST135 maybe, as with a harmonic mount I do not have to perfectly balance it all the time as I switch up a lot between my 4 telescope rigs. I think iOptron HAE mounts are just a bit better than ZWO… but maybe not!
[unknown] I will probably go with a RST -135 next but I do not need it yet!
Is it work going to the 135E instead?
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Kevin_A oh didn’t realize you were in Ontario, I’m in Burlington so not too far 
Yeah being an iOptron mount user, I looked at the HAE series before pulling the trigger on the AM5 but they seemed a bit too expensive and heavy given their weight capacity…maybe I wasn’t comparing to the right models. Anyway I will try highspeed guiding with metaguide and see if I get better results on the AM5. Based on w7ay experience, the RST seems to be the way to go…for my portable rig use case I’m not sure the price point is justified. I think the RST maybe the way to go if it’s the only mount but at least based on my experience, the older worm gear tech offers a better cost to performance combination.
RainbowAstro uses the gears from Harmonic Drive LLC (USA, Germany and Japan plants), not Chinese copies.
RainbowAstro's parent company is RainbowRobotics, who have been building robotic arms for the industry for quite some time now. Before their strain wave gears, they had also been building observatory quality (read: humongous sized) mounts. RainbowAstro/RainbowRobotics actually share the Robotics Labs, and many faculty and researchers with University of Nevada (Las Vegas). RainbowRobotics CEO is an astrophotographer (eclipse chaser), and spun off RainbowAstro after collaborating on Harmonic Drive mounts with Hobym (another Korean mount manufacturer) before. As to precision, see this (watch it track the rim of the Sun):
https://www.youtube.com/watch?v=PzWc7adS-RY
- you should see how clean their mount protocol commands is compared to ZWO's mount protocol. Engineers (retired long ago) like me try to spot bullshit by looking at things like that.
4) (tongue in cheek) they do the right thing with Local Sidereal Time. ZWO is using Local Time and Daylight Saving Time to figure out the timing for ASIAIR (and I presume their mounts). Now that the US has swithed to DST, we should see all sorts of Meridian Flip problems on this forum again.
Chen
w7ay really good to know, I expected the higher price point to be due to the better hardware components….they should really advertise this more of on their website/product pages. I saw that the rst uses servos rather than steppers so that to me indicated a general approach based higher end components.
eyecon yes, I am in Belmont between Port Stanley and London. I am in a Bortle 4 sky so it is nice to be out of the city lights. I am retired now so that helps with late nights! I built a new house 4 years ago in a dark place but neighbours are starting to ruin my skies so I am planning another move and that will include a real observatory…. So for now a portable mount is good but maybe a better harmonic drive will be still best in my future plans.
