New mount for my EdgeHD 9.25 - Forums

Topic starter

Feb 12, 2025

Hi.

I'm looking for a new mount for my EdgeHD 9.25 (my old mount was a CGX that died on me) with a full image train. Portability is not relevant for me and I only do astrophotography.

The CEM70 looks interesting but I was wondering what you guys use with a payload of this size - and maybe what you can recommend and/or have experience with.
I haven't settled on a budget just yet but I'm thinking somewhere around $4000 give or take.

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Tony Gondola

Frequent contributor

Feb 12, 2025

I don't have any experience with mounts in that price range but I have had excellent results from my EQ6R-Pro. Average guiding on a steady night is about 0.25". That's with a steel tube 6" F/6 Newtonian and an 80mm F/5 guide scope.

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Lasse Skov

Topic starter

Feb 12, 2025

Tony Gondola:
I don't have any experience with mounts in that price range but I have had excellent results from my EQ6R-Pro. Average guiding on a steady night is about 0.25". That's with a steel tube 6" F/6 Newtonian and an 80mm F/5 guide scope.

Hi Tony

Thanks for sharing. Cheaper options are always appreciated!

Kristof Vandebeek

Feb 12, 2025

I use a 10” f/5 newtonian with mono camera, filterwheel, coma corrector and OAG on a second-hand AZEQ6. I also have a visual finder scope and a small camera-based finder-scope mounted on top of the OTA, next to the necessary USB hardware and cabling. Even though the 10” is already big by itself, I made it a bit longer by adding a dew shield to protect it from stray light. Balancing goes easy (the mount doesn’t swing in all directions, as I had with my iOptron GEM28 with a smaller scope).

Guiding RMS is around 0.25” - I shoot 10 minute subs without issues. I chose the AZEQ6 over the EQ6R for its’ “better”azi/alt adjustments, as I usually set up and tear down before/after a night of imaging. If I had to buy a new mount, I’d buy the AZEQ6 again.

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Christoph Paulus

Feb 12, 2025

I bought an EdgeHD 9.25 about 1.5 years ago. After a few weeks of back and forth between the CEM70 and the HAE69 I went for the HAE69EC. It has its problems but in the end the most important criterion was the harmonic drive with very low to no backlash. I had a hypertuned HEQ5 Pro before which still had some erratic backlash I couldn't get rid of. I read many reports of backlash issues with the CEM70, so I went for the HAE69EC. EC mainly because I thought I wanted a mount for the next 10 years.

I'm pretty happy with the mount, especially as there's basically no backlash. Guiding the C9.25 at F/10 with around 0.3”. There's a YouTube video discussing some problems with the mount which I also commented with my experience. In case you are interested, let me know, then I'll try to find it (already a couple of months ago).
I also like that it can be easily changed to an Alt/Az configuration so that it can track satellites with SkyTrack in the continuous tracking mode.

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Lasse Skov

Topic starter

Feb 12, 2025

Christoph Paulus:
Christoph Paulus

Hi Christoph

I would be very interested in that video. How do you find polar aligning the HAE69EC with the weight you got on it? My AM5 gets increasingly dodgy to PA when the the payloads gets above 7-10 kg.

Mark Fox

Feb 12, 2025

Lasse, I upgraded my EdgeHD 9.25 to the EQ6R-Pro a couple years ago and get reasonable (sub-second) guiding. My total OTA weight has to be over 30 lbs (OTA, dewshield, dew heater controller, BULKY Celestron reducer, OAG, EFW, ASIAir, full-frame 2400MC, minus the finderscope). It's a tank of a mount and seems to be capable of the advertised 20kg (44 lbs) FOR ASTROPHOTOGRAPHY specification, as it is written in the mount's manual.

My personal observations:

The retractable counterweight shaft was wobbly when used fully extended. When fully extended (due to balancing versus the weight of the entire image train), I would get the slightest bump of a few seconds of arc, maybe every 10-20 minutes, as the shaft resettled due to regular RA motion. I solved that with a new internal delrin washer at the internal end of the shaft. But if you can achieve counterbalance with the shaft maybe 3-4 inches retracted, it would definitely be a non-issue. In hindsight, I could have achieved counterbalance without fully extending the shaft and probably didn't need to screw around with the delrin washer.
When new, my mount came in a little tight on both RA and DEC axes. Definitely seek out Cuiv the Lazy Geek's easy de-tensioning procedure that worked out great. It improved tracking and also makes for much easier balancing.
My mount did NOT have the periodicity issue that others have written about (120 second worm gear period, or 10 second belt tooth catching/releasing issue). The worst periodicity I see (according to PHD2 frequency analysis) is maybe 0.6 seconds RA error at 480 seconds -- which your OAG will easily mitigate.

Don't get me wrong - I don't regret my choice. +1 for EQ6R-Pro.

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Lasse Skov

Topic starter

Feb 12, 2025

Mark Fox:
Mark

Hi Mark.

Thank you very much for your detailed response. I'll definitely add the EQ6R-Pro to my watch-list.

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Christoph Paulus

Feb 14, 2025

Here are 2 videos:
https://www.youtube.com/watch?v=Q9MYfrigo_k
https://www.youtube.com/watch?v=9P37xXVRCvA

I commented under the second video (also about polar alignment):

I bought the HAE69B EC about a year ago and I can agree with most of your findings (except backlash):

Polar alignment: There's a lot of backlash in the altitude adjustment screw. Together with the lubricated hinge it moves when tightening. I couldn't even clamp it strong enough by hand to not move when the mount is moving (center of gravity shifting). I experienced some drifting on the first subs. I ended up removing the lever/bolt and using a wrench for tightening. I also purchased an iPolar (this should really come with the mount for the price) and I anticipate the movement caused by tightening with the wrench. Works fine now, getting good polar alignment but it's a major design flaw. A week ago I also discovered a loose bolt at the top of the tripier which caused the top plate to move in altitude. Fix was easy of course but yet another drifting issue.

DEC/RA movement: Interesting find, I also noticed this when doing lunar, solar and planetary imaging. Never noticed something like this doing deep sky (not actively using the Commander in this case).

Unguided: Totally agree, I expected much better results by the encoder. I'm running at 3 seconds for my guide exposures which are totally fine, but when I let PHD do some analysis (no guide outputs) the drift starts soon after.

Guiding accuracy: Also mostly around 0.5, when seeing is good sometimes also 0.3

Backlash: Luckily mostly not existent, sometimes maybe 200 ms. Very happy with that since my previous much cheaper mount had huge issues with backlash which I couldn't fix due to production errors.

Overall I'm quite happy with this mount but I expected more for the price. I can live with not being able to do unguided exposures since I always image at longer focal lengths but I bought the version with the encoder "just in case". Very happy with guiding and backlash. Biggest issue for me is the polar alignment with the design flaw and the iPolar. The iPolar works great but it should really be included for the price. In the end I now need longer for polar alignment than with my previous mount

Let me know if you have any questions.

Christoph Paulus

Feb 14, 2025

Two additions: I use the HAE69 with the counterweight. It's technically not required but I sleep better with it

I also use the mount on the iOptron tri pier. Together with the counterweight the whole setup is very sturdy.

Stacey Baczkowski

Feb 14, 2025

I have an HAE69C and think it is great. Once I got guiding set up, it is a workhorse. I usually have so-so seeing in a Borttle 5 area and regulalrly get 0.4-0.6 rms guiding. (Once I got that guiding, I have’nt tried to refine it further) I control it with an ASIAir plus and polar alignment is very easy. My total imaging set-up is about 30 pounds and the mount handles it with ease. I have one issue - when I use it in station mode, meridian flips fail. The mount does not move. When I have the mount connected to the Air via a cable, meridian flips work flawlessly. I don’t know if it is the mount or a bug in the Air, but easy to work around. I don’t use a counterweight and I use the iOptron tri pier. The tri pier is very sturdy. I don’t have the hand controller, iPolar, or encoders and don’t feel like I am missing out on anything since the Air works with the mount.

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YingtianZZZ

Feb 14, 2025

I use CEM70 for Skywatcher 8'', 10'' and Edge11HD, both work good!

Rick Krejci

Feb 14, 2025

Lasse Skov:
Christoph Paulus:
Christoph Paulus

Hi Christoph

I would be very interested in that video. How do you find polar aligning the HAE69EC with the weight you got on it? My AM5 gets increasingly dodgy to PA when the the payloads gets above 7-10 kg.

I had the HAE69EC with about 55 lbs/25kg without a counterweight and with a large lever-arm (a 250mm Quattro with a 65mm refractor on top). It generally handled guiding with that just fine, but PA was a bit dodgy for me like the video mentions. I'd rough PA with the bolts a little loose and then tighten them a little more for final PA. Still shifted when doing the final tighten, but was "good enough".

Basically, if your mount can't sit flat on your pier/tripod with all the bolts loose (like most Harmonics with a very heavy load), then you will likely experience some shift when locking down mount after PA adjustments.

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Anne-Maree McComb

Feb 14, 2025

Hi Lasse, I have the CEM70EC and wish I had saved some money and bought the Skywatcher EQ8 for my heavy 10" reflector (17kg). I just don't see the value in this mount at 3 times more expensive than the EQ6R. I also have the Skywatcher HEQ5 and EQ6R. I love both the skywatcher mounts and they hardly ever give me any grief. I am running my Takahashi Epsilon 180ED on the EQ6R, this scope is a fraction heavier than your 9.25 and it is a match made in heaven. Before purchasing the Tak, I had the 17kg reflector on the EQ6R for 2 years and it ran beautifully except if there was strong winds. Given the length of that scope, it was unsurprising. What I don't like about the CEM70EC, is it swings like a pendulum. It is incredibly hard to balance and I am disappointed in the guiding stats I am getting as they are no better than I was getting with the EQ6R. Both mounts give me about .6 - .8" with the heavy scope. I also had to have it repaired as the knobs scraped and physically stopped the movement after meridian flip to the north (I'm in the south). It also had to have the RA professional adjusted due to the squealing noises I was getting. Not a happy purchaser and I wouldn't bother with an Ioptron again.

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JohnAdastra

Feb 15, 2025

I have a C925 Edge and have been using a Losmandy G11 with it since 2017. First I used the stock G11G2 which gave decent results, but then I moved on to another G11 modified with OnStep. If you are the the handy type, you can find an older G11, rebuild, and add an OnStep controller and save yourself some big money. My OnStep version now outperforms the original by a mile with nice rounds stars. But if you have the budget, you should get the best you can afford as the mount is the keystone over which all rigs are built. Also note the weight of the mount as well if you are a set up and tear down every time person. The CEM70 is a bit of a boat anchor might be a challenge to those of AARP ages

. I'd probably get the EQ8-Rh with the encoders if it didn't have the high price tag. Perhaps a Paramount MyT is more in line with your budget.

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Dave Rust

Feb 15, 2025

I've been using the iOptron CEM40 with the 925 for four years with excellent results. At 26lbs with accessories, the scope is still well under 40lbs max. Guides whole subs around .45 most nights (925 pixel res is .317. Close enough). At one point, the RA lock was growing loose. I sent it in to Boston, where the whole mount was rehabilitated (new worm, ring gear, latest electronics, cleaned/regreased, etc.) Cost $250 bucks. Now runs better than new.

The CEM40 works well because the Celestron light buckets are smaller wind sails than longer scopes, thus reduced leverage. Less horsepower is needed to keep them on track.

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Ashraf AbuSara

Feb 16, 2025

I am amazed by how many HAE69c and EC owners are on this thread. I thought I was the only one!

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Observatório Astrográfico do Boqueirão

Feb 17, 2025

I don't own an EQ-R Pro, but from my knowledge and point of view, she have my vote also.
You need to think two things regarding traditional EQ mounts vs the Harmonic mounts at high focal lenghts. ZWO for example don't recommend in their Harmonic mounts, focal lenghts above 900mm (never understood why, but they don't).
The other thing regarding SCT scopes and similars. They are slow, which in guiding requires looping exposure times around 2-3s or more to have a proper guiding mainly using an OAG. This makes a very difficult job to the Harmonic mounts, since they play nice with values around 1-1.5s. You can go above that, but you'll have problems.
Another thing is they traditional are small and compact. High focal lenghts even in a concrete pier using a Harmonic mount, will give you problems related with vibrations which will be magnified by the high focal lenght of an SCT.

Those are my thoughts.

Regards,

Cesar

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Lasse Skov

Topic starter

Feb 17, 2025

Thank you very much to all who chimed in here. It's really valuable information.

I'm torn between regular worm-gear mounts vs harmonic mounts. As a few of you mentioned SCTs are wind sails and its often windy here in Denmark.
A bulky boy like the EQ8 or CEM70 could probalbly help negate this. On the other hand harmonic mounts are really easy to set up (I own an AM5 for my Redcat 51).

You've give me something to think about. Thanks!

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Lasse Skov

Topic starter

Feb 17, 2025

Observatório Astrográfico do Boqueirão:
I don't own an EQ-R Pro, but from my knowledge and point of view, she have my vote also.
You need to think two things regarding traditional EQ mounts vs the Harmonic mounts at high focal lenghts. ZWO for example don't recommend in their Harmonic mounts, focal lenghts above 900mm (never understood why, but they don't).
The other thing regarding SCT scopes and similars. They are slow, which in guiding requires looping exposure times around 2-3s or more to have a proper guiding mainly using an OAG. This makes a very difficult job to the Harmonic mounts, since they play nice with values around 1-1.5s. You can go above that, but you'll have problems.
Another thing is they traditional are small and compact. High focal lenghts even in a concrete pier using a Harmonic mount, will give you problems related with vibrations which will be magnified by the high focal lenght of an SCT.

Those are my thoughts.

Regards,

Cesar

Hi Cesar.

I've never heard about longer guiding exposures for longer focal length telescopes (I also use an OAG). Interesting.

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Christoph Paulus

Feb 17, 2025

I can only speak for my mount but I don't have any vibration issue at all. I'm using 3s guiding exposures for both my Skywatcher 1000/200 PDS as well as my EdgeHD 9.25. I only adjust the gain a bit. I read that harmonic mounts like/need short guide exposures and I tried it but I haven't seen a difference. Maybe it's because of the encoder, I don't know.

I had some vibrations in the past which were caused by the fan of my ASI 533. Replaced the stock fan by a better one, that solved that problem.

I shot last night with the setup again at F/10 in varying seeing conditions. Guiding was 0.3” to 0.5”. I only checked the subs quickly but it seems that I can use almost 100% of them. With my HEQ5 (1000 mm, F/5) I had times where I had to throw away 50% of subs.

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Ashraf AbuSara

Feb 17, 2025

Christoph Paulus:
I can only speak for my mount but I don't have any vibration issue at all. I'm using 3s guiding exposures for both my Skywatcher 1000/200 PDS as well as my EdgeHD 9.25. I only adjust the gain a bit. I read that harmonic mounts like/need short guide exposures and I tried it but I haven't seen a difference. Maybe it's because of the encoder, I don't know.

I had some vibrations in the past which were caused by the fan of my ASI 533. Replaced the stock fan by a better one, that solved that problem.

I shot last night with the setup again at F/10 in varying seeing conditions. Guiding was 0.3” to 0.5”. I only checked the subs quickly but it seems that I can use almost 100% of them. With my HEQ5 (1000 mm, F/5) I had times where I had to throw away 50% of subs.

I have both the encoder and non encoder based version, and the encoder on the RA in the HAE69ec definitely helps push the exposures to 3-5 seconds.

Hans P. Strifeldt

Feb 17, 2025

Christoph Paulus:
I had some vibrations in the past which were caused by the fan of my ASI 533. Replaced the stock fan by a better one, that solved that problem.

Sorry for jumping in - it is not my intention to hijack the OP's thread - but may I ask with which fan did you replace the stock one? I have a similar issue with my 533MM (and indeed my 294MM).

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Nicolas Molina

Feb 17, 2025

Hi!

I started with an AM5, with good results. However, the astrophyscis Mach2 Gto is on another level. PHD2 graphs are almost flat, with very few corrections. I use it on a steel pier, and my EdgeHD is with a Moonlite focuser and OAG.

Kind regards

Christoph Paulus

Feb 17, 2025

Ashraf AbuSara:
I have both the encoder and non encoder based version, and the encoder on the RA in the HAE69ec definitely helps push the exposures to 3-5 seconds.

Thanks! Good to know it was worth it

Hans P. Strifeldt:
Sorry for jumping in - it is not my intention to hijack the OP's thread - but may I ask with which fan did you replace the stock one? I have a similar issue with my 533MM (and indeed my 294MM).

Noctua NF-A4x10 FLX
If I remember correctly it's a bit thicker than the stock one, so mounting was a challenge: