Can the AM5 handle longer focal lengths?

ZWO recommends you don't use the AM5 with telescopes that have a focal length greater than 900mm. But will that hold up to this test?

[@amp2amp800]

Hi Mr Wilson. The 900mm argument is all about camera sampling rather than the mount. The great guiding numbers you're getting is substantially thanks to the OAG. The AM5/EQ6 both kinda just do what they need to do. So yeah, you have a nice lightweight rig now and its certainly up to the task!

[@slapastronomy8646]

Excellent image! Congrats on the new mount!

[@samshornvibes]

A quick 30 second sequence of you taking the pictures at night would've put this video to the next level. Overall a great test and review!

[@MrWilsonsChannel]

Great suggestion! I'll do that for the next one. Thanks 😊

[@TheNorthDevonOrganist]

great job and great image

[@Kelli.Hicks.5]

Hey, Mr. Wilson! 🙋‍♀️ I love new gadgets. Have fun!

[@MrDirtyRod]

When my CGX-L was down, I popped my 26lbs C8 plus reducer on with the CW and got the same results over several weeks. Recently, I ran it at the full 2032 and it was running at .5" -.7" consistently over several weeks. I did add the CW though as I saw images skipping around when the scope was pointing towards the zenith and figure it was related to having the OTA at an extreme angle and the entire rig was moving. Running the CF tripod with a 12lbs CW in the weight bag.

[@MrWilsonsChannel]

I put my battery pack in the bag for extra tripod stabiliy. Good to hear your getting similar results from your rig. I think this thing is a beast! The tracking reaulta were just as good as my EQ6-R pro, if not better... and all at a fraction of the size and weight

[@calimark7448]

I've been using the AM5 since last Sept with my Askar FRA400 setup. Very happy with those results. I just got the EdgeHD 9.25 and I must say it works, but the slightest breeze will skew your tracking numbers. I've only had a few nights with it and every thing is coming out very soft, so... I'm just getting things sorted out so take that into consideration... I am using the .7x reducer as well. Clear skies!

[@MrWilsonsChannel]

This is great information. Are you using the zwo carbon fiber tripod? I've read some people are getting better wind tolerance by adapting a heavier tripod from a different mount. Any experience with that?

[@calimark7448]

@@MrWilsonsChannel Yes. I recently got the iOptron tri-pier. (the 8034) I had some initial issues with the top plate rocking... yeah... anyway, fixed that(re-drilled attach hardware to 6mm and used countersunk screws, then I was able to add 3 holes to mount the AM5 directly) and had the first night with it. It was ok but I'm still having growing pains with the EdgeHD. It is a much more stable platform for the weight vs the TC-40. I never had issues with my FRA400 setup, but that was pretty low profile compared to the big EdgeHD. I do have some counterweights on the AM5 that I'm borrowing from my Star Adventurer GTi.

[@AmatureAstronomer]

Nice.

[@seemantadutta]

The 900mm recommendation stems from the image scale with the most popular ZWO cameras and their pixel size. It has nothing to do with the mount itself, which can easily handle that load. Enjoy your mount!

[@DSOImager]

Pretty impressive guiding results.. and on the carbon tripod with no counter weight no less! Will be interesting if it can hold that kind of guiding consistently. How was the seeing conditions that night?

[@southbronxny5727]

Looks great....If you waited a bit more, you could've gotten version 2.

[@MrWilsonsChannel]

Yeah... i noticed that 😡 unfortunately I didnt know a new version was coming. Foiled again 😉

[@mikehardy8247]

That's always been my fate😢

[@KJRitch]

Thanks for addressing this issue. Most AM5 and other strain wave mounts are tested with lower focal length optics that make guiding easy compared to a SCT with an OAG. My understanding is the Periodic Error of the AM5 is the reason for the 900mm guidance. What is your PE of you AM5 from the included sheet that comes with the AM5? Now that ZWO has released the updated version of the AM5, the AM5N, which has half the Periodic Error plus improved weight capacity, 33lbs without counterweight, 10", should the new model be better for longer focal lengths, theoretically. I have a C8 SCT with Starizona 7.1 focal reducer (1442mm), Celestron OAG with ASI174mm mini guide camera and a ASI071MC Pro. My mount is an AVX and it doesn't guide consistency so I'm looking for a new mount. I didn't want to take the chance on a strain wave mount due to their excessive PE and owners of them state you have to guide around 0.5 sec exposure but with an OAG I find at that exposure my SNR in PHD2 is very low and I get lost star alarms. I noticed a Celestron OAG on your rig. What exposure are you using for guiding? My C8 SCT is about 19lbs with the image train. Have you had consistent guiding at various locations in the skies and can it tolerate some wind? My other alternative was to go with something like an iOptron CEM40. Thanks.

[@MrWilsonsChannel]

Max/min PE is 8.2/4.4. I got mine right before the new one came out. I think mine probably contains the new gearing since the PE is so low. It's in line with what the new ones are like. I got an asi220 mini guide cam in preparation for this mount. It has really good QE and the celestron oag has a HUGE prisim which helps me fit more stars in its field of view. Both let me get away with away with pretty short guide exposures around 0.2 seconds. I've read the shorter the exposure the better the guiding with the strain wave design. I've had no trouble keeping guide stars at 0.2 second exposures so far. I think I'll do some experiments on this: short vs long guide exposures. You just gave me a new video idea 🙂

[@KJRitch]

What is your main camera model? Did you shoot M101 at 2032mm? I have the ASI174mm mini which has a larger sensor, 11.3x7.1mm and even a higher QE than your model. I use NINA and PHD2 I can’t seem to use exposures less than 1 second even in Bortle 2 skies. I’ve tried 0.5 sec but I loose the star often. Maybe ASIAir works better at guiding vs PHD2, although I heard ASIAir uses PHD2. I have the prism on my Celestron OAG set at the lowest setting. Have you tried 1 sec exposures for guiding and what were the guiding results. Did you shoot M101 at 2032mm FL at 5 minute exposure and how many exposures did you take? What software did you use to process? Thanks. I’m looking forward to more AM5 videos with you SCT.

[@chrislee8886]

Thanks for this. My experience with the same scope and this mount was a little different in that my OAG could not capture enough detail of stars to autoguide with only 0.5s-1s capture time vs my 2s on EQ6. This level of integration time seems to be a feature of strainwave mounts. How then did you find your OAG able to perform? Anything unusual in your set up? Looking for tips!

[@MrWilsonsChannel]

I'm actually working on a new video right now that addresses these issues, so be sure to look out for it. I use the celestron page which has a massive prism. That increases the odds of catching a star somewhere. But the real secret is the guide camera. I use the asi 220mm mini which has a phenomenal quantum efficiency. I crank up the gain and can easily guide with 0.2s exposures

[@chrislee8886]

@@MrWilsonsChannel interesting- i have the ASI220mini matched exactly to the window of the ZWO upgraded prism but still smaller than Celestron… i tend to use 300 as the gain out of 400 with this camera (and dark frame in operation) and this is what i used during my two week trial with the AM5 last year…

[@MrWilsonsChannel]

@chrislee8886 interesting... Ive never seen an option to use a dark frame with my tracking camera... I'll have to investigate that further. Are you using the asi air pro, or plus? I have the older pro, so maybe it doesn't have that option? But I've never looked for it either, so it's possible it's there. Either way, I know I'm not using that option, so maybe that has something to do with it? If you use a longer exposure, can you see stars? Just curious if the back focus of the tracking camera might be out of sync with the primary camera?

[@user-vu3xx6wk6w]

I have the same scope and was wanting to get the same mount. Any specific reason why the company does not recommend using with the OTA? Is it possibly how it would do with stability in wind?

[@MrWilsonsChannel]

I've definitely read many complaints about its performance in the Wind. I think that's more of a function of the lightweight carbon tripod however. I've seen other people adapt heavier tripods from other mounts for use with the am 5 and have got better tracking results in Wind. But I haven't tried that for myself yet. They used to have the 900 mm focal length limitation listed on the product page, but I noticed they have removed that. I think they realize that it actually performs well at longer focal length

[@brod5352]

I'm using the Pegasus Astro NYX-101 with my 8" Edge HD and it works absolutely fine. Just make sure you have a good polar alignment and calibrate close to the celestial equator and you should be good to go. I typically get under 1 arc second and on average in the 0.67 range. Sometimes it will dip down into the 0.5 range but it doesn't stay there. I'm assuming it's all atmospheric changes more than anything. I do like the AM5. But will keep my NYX-101 for now. ;0)

[@MrWilsonsChannel]

I considered the 101, but it was a little outside my price range this time around. It looks like a really solid mount

[@brod5352]

@@MrWilsonsChannel Agreed. I was lucky and had some extra cash I could toss in as it's not cheap. My reason was the payload. I want to move up to an 11" Edge HD and with my current setup that might be more than the AM5 can handle. And I don't like to push my mounts. My tip is to calibrate PHD2 as close to the Celestial Horizon as you can. It has made a world of difference in my guiding. Instead of being around 1.18 arc seconds I'm not down as low as 0.54. Typically around 0.75 but still quite good. So calibrate near the Celestial Equator.

[@MrWilsonsChannel]

@brod5352 the asiair gives me a warning with the same advice if i calibrate too far from the equator, but I haven't had time to experiment with the difference yet. Thanks for the advice! I'll include this tip in my future video on this topic. 🙂

[@robertgrenader858]

Is the weight limit on the FAQ with or without the counterweight kit?

[@MrWilsonsChannel]

The AM5 can hold a 13kg payload without a counterweight, and a 20kg payload with the addition of a counterweight. The counterweight itself should not exceed 5kg and the weight of the counterweight itself does not count against the payload capacity. Likewise, the weight of the optional counterweight bar also does not count toward the payload capacity.

[@dmcmahon999]

Please confirm the scope that you are using. 9.25?

[@MrWilsonsChannel]

I have an older model celestron nexstar 8" sct. Focal length of 2032mm. I have experimented with it at the full 2032, with the reducer which brings it down to 1280, and with an 8" RASA with a 400mm fl. I got great results from them all.

[@dmcmahon999]

@@MrWilsonsChannel I’m looking at Rasa 8 vs Refractor. Love the low f ratio of the Rasa. For wide field what are your thoughts?

[@MrWilsonsChannel]

@dmcmahon999 it's a great scope, but honestly, i don't like it because it isn't very flexible. For example, I can't attach my filter wheel to it. Also at f2 it requires special filters. That means I have to buy one set of filters for my C8 and another set of filters for the raza. I'm not willing to do that, so I just end up using the C8 filters for the Raza which lowers the amount of light that can be transmitted and effectively eliminates the F2 benefits. If I had to do it again, I'd probably get a refractor at around f4 or f5

[@dmcmahon999]

Thank you sir.

[@millsbobster]

nice video, and i love your channel. however, you seriously undermine your credibility by saying that 2000mm is “almost three times” 900, when it’s barely over 2x.

[@SKYST0RY]

Is that a C6?

[@MrWilsonsChannel]

C8