USB problems: I found the connector to the board had worked loose making performance intermittent. You have to take the Dec saddle apart to access it.
Dec performance: got worse for me so did complete rebalance. I stripped down the Dec assembly to access the worm screw on the left side and adjusted meshing of worm gear. rms dropped from 1.2 down to 0.4 typical.
RA performance was also poor. So I stripped down RA housing to access the worm gear left hand side grub screw - that was loose. Adjusted meshing and rms is also down from 1. 2 to around 0.7 to 0.4.
I have not tried adjusting belt tension yet.
I also now do 3D balancing. Not sure which adjustment made the most difference but now my resolving power is seeing and not mount limited.
Can you please give a brief description of your adjustment of the worm mesh?
The manual shows where the screws are but gives no real direction other than stating not to exceed 1/4 turn, which is kind of useless.
On other mounts, I would tighten until the mount started to bind, then back off a bit. But I’m concerned that the process might be different based on the spring loading mechanism (which is also conveniently not described).
Sorry for the late reply, enjoying sunshine but no dark.
The Cem70 normal process is very similar to other mounts; make small adjustments. Tighten the lock screw and slew. Back-off a little bit if there is binding.
My tracking problem was bigger than typical, very unpredictable and wide swings. There is a set of not user accessible screws for the other end of the worm shaft, they were loose. The result was the worm shaft pivoting more than it should. I suspect it made the thread less perpendicular to the teeth. Adjustments were either binding or too loose with no sweet spot middle.
Next month when I start imaging again I hope to find everything still good.
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Been using mine since January and am very happy with it. Last night was not so terrible seeing, and calm for once, and guiding ran under .7” using an OAG on my 9.25 Edge. When guiding deteriorates due to wind or seeing, stars remain round, just bloated, FWIW. My two complaints are, first the USB & power connections are a little touchy….didn’t have much trouble at first, but starting this spring had some real issues getting my 268M to connect to my laptop via the CEM hub. What finally worked was to power the mount and connect it to my laptop first, then connect power to the RA hub with the 268m and dew heater unplugged, get the guide camera going, *then* connect the 268 and once the chip is cooled, connect the dew heater…… Sometimes, though, the ioptron software on my laptop doesn’t see the mount when i connect it at the start. Like last night when i restarted both the mount and laptop at least twice before it worked.
Second issue is it’s LOUD!…all sorts of noises from cement mixer to coffee grinder…..kinda’ disconcerting, but it works!
Cheers,
Scott
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The CEM 70 that I originally bought about 20 months ago performed OK but did have some underlying problems which only became apparent when I started doing deepsky lucky imaging at an image scale of about 0.5 arcsec/ pixel. There was a high frequency (about 1 hz) wobble in the RA movement which caused star shape distortion with elongation along the RA axis and a consequent loss of resolution. It is a subtle problem since movement on this time scale is too fast for PHD2 to pick up since the average position at 2-3s intervals isn't changing but it nevertheless does impact the image.
I don't think that newer CEM70s have this problem - in any case my replacement doesn't and I have read elsewhere on the internet (Cloudy nights forum) that the issue possibly related to some of the driver boards controlling the RA and DEC movement.
In case anyone is interested in the gory details (which might possibly be relevant to analysing mount performance in general) I posted a detailed analysis - both before and after the fix - in the tutorials section of Robin Glover's Sharpcap website
https://forums.sharpcap.co.uk/viewtopic.php?p=31153&sid=4126b10e5551b6178b4e78f611da48e1#p31153
best wishes
Tim
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I just received my mount back from iOptron service. Brand new mount that had a strange RA curve as captured by PEMPro. I initially requested an exchange, but my vendor wanted it to go to iOptron for service. I was adamant with my vendor that I would not pay for shipping or a new worm based on my knowledge of how to handle the mount prior to buying it. I've seen several reports where folks had to pay for return shipping AND a new worm because iOptron will say that improper handling of the mount head (clutch engaged versus disengaged using the hex key lock) causes this. However, my guess is that there may have been a batch of mounts shipped with bad RA worms. Guess what? They couldn't get the RA into spec so they replaced the worm.
It is monsoon season here in AZ, so I only had one limited test to check it after getting it back, but it looks really promising on the first curve recording. My recommendation to new buyers is to check your mount immediately and go for an exchange if you have doubts. The service took 2 months.
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My CEM70G will guide accurately with the built in guider controlled by PhD with me using a 10RC with ApexL and QHY294M Pro. I initially got the mount for the RASA 11 because I didn't think it would guide well for longer focal lengths, but I was pleasantly surprised to be proven wrong on that. The USB 3.0 hub is very nice too.
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Scotty Bishop:
My CEM70G will guide accurately with the built in guider controlled by PhD with me using a 10RC with ApexL and QHY294M Pro. I initially got the mount for the RASA 11 because I didn't think it would guide well for longer focal lengths, but I was pleasantly surprised to be proven wrong on that. The USB 3.0 hub is very nice too.
I don't agree with this at all.. I have issues guiding and they all lead to the iGuider's FL being too little for a C11 Edge FL... even so less with a RASA... I still can't get decent guiding out of mine(1.0 RMS on average) and the mount doesn't center targets even after 3-star aligment... Still struggling with this.. I can't believe ppl are getting .3 RMS with this mount... maybe with a 10lb payload...
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Julio Cruz:
Scotty Bishop:
My CEM70G will guide accurately with the built in guider controlled by PhD with me using a 10RC with ApexL and QHY294M Pro. I initially got the mount for the RASA 11 because I didn't think it would guide well for longer focal lengths, but I was pleasantly surprised to be proven wrong on that. The USB 3.0 hub is very nice too.
I don't agree with this at all.. I have issues guiding and they all lead to the iGuider's FL being too little for a C11 Edge FL... even so less with a RASA... I still can't get decent guiding out of mine(1.0 RMS on average) and the mount doesn't center targets even after 3-star aligment... Still struggling with this.. I can't believe ppl are getting .3 RMS with this mount... maybe with a 10lb payload...
It works out well for me for even the Meade LX850 12" SCT. I would first check your firmware and make sure you are 100% up to date (that made a huge difference). Then make sure your iGuider is focused well (mine was not at first), then make sure you lock on with GPS so your time and site is good and make sure the DST setting is right in the hand controller.
Do the three star alignment on the first 3 stars it picks if you can because they are going to be the brightest ones. I will also use a finderscope to help me get the stars centered and then fine tune it on screen. I also do my initial focus with a Bhatinov mask at this time because it makes any autofocus go really nice and fast.
When you do your guiding calibration in PhD make sure you have everything set up for a proper PhD calibration including focal length, sensor, guide rate matching in ascom and PhD, where you do your calibration, number of steps, etc. and if you are still running into issues I would check and see where you are getting the errors at. If in Dec get a small weight to balance Dec (that is a problem in the CEM design it seems).
If you are still running into problems I would definitely contact iOptron support since they have always responded to me and helped me through any issues or answered any questions I had.
Of course that being said, while the iGuider works awesome with my 620mm focal length on the RASA 11 and was a giant surprise that it worked great with my 10RC and ApexL at 1320mm fl, you running at 2800mm focal length is a whole other thing because at that focal length you're better off with OAG. It may not be the weight that is your problem, but the focal length itself. Remember, seeing that a short focal length guidescope doesn't see will definitely be seeing that your C11 Edge will see.
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Got my cem70 a few weeks back and been very happy with it. Guiding performance is great and so much easier to handle than the AVX in every aspect.
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Scotty Bishop:
Julio Cruz:
Scotty Bishop:
My CEM70G will guide accurately with the built in guider controlled by PhD with me using a 10RC with ApexL and QHY294M Pro. I initially got the mount for the RASA 11 because I didn't think it would guide well for longer focal lengths, but I was pleasantly surprised to be proven wrong on that. The USB 3.0 hub is very nice too.
I don't agree with this at all.. I have issues guiding and they all lead to the iGuider's FL being too little for a C11 Edge FL... even so less with a RASA... I still can't get decent guiding out of mine(1.0 RMS on average) and the mount doesn't center targets even after 3-star aligment... Still struggling with this.. I can't believe ppl are getting .3 RMS with this mount... maybe with a 10lb payload...
It works out well for me for even the Meade LX850 12" SCT. I would first check your firmware and make sure you are 100% up to date (that made a huge difference). Then make sure your iGuider is focused well (mine was not at first), then make sure you lock on with GPS so your time and site is good and make sure the DST setting is right in the hand controller.
Do the three star alignment on the first 3 stars it picks if you can because they are going to be the brightest ones. I will also use a finderscope to help me get the stars centered and then fine tune it on screen. I also do my initial focus with a Bhatinov mask at this time because it makes any autofocus go really nice and fast.
When you do your guiding calibration in PhD make sure you have everything set up for a proper PhD calibration including focal length, sensor, guide rate matching in ascom and PhD, where you do your calibration, number of steps, etc. and if you are still running into issues I would check and see where you are getting the errors at. If in Dec get a small weight to balance Dec (that is a problem in the CEM design it seems).
If you are still running into problems I would definitely contact iOptron support since they have always responded to me and helped me through any issues or answered any questions I had.
Of course that being said, while the iGuider works awesome with my 620mm focal length on the RASA 11 and was a giant surprise that it worked great with my 10RC and ApexL at 1320mm fl, you running at 2800mm focal length is a whole other thing because at that focal length you're better off with OAG. It may not be the weight that is your problem, but the focal length itself. Remember, seeing that a short focal length guidescope doesn't see will definitely be seeing that your C11 Edge will see.
Thanks, I just got my Celestron OAG out to put it on and see if it helps. Thanks for the suggestions.
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D. Jung:
Got my cem70 a few weeks back and been very happy with it. Guiding performance is great and so much easier to handle than the AVX in every aspect.
Congrats... what is your payload on this? obviously iOptron fixed a few things.
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Julio Cruz:
D. Jung:
Got my cem70 a few weeks back and been very happy with it. Guiding performance is great and so much easier to handle than the AVX in every aspect.
Congrats... what is your payload on this? obviously iOptron fixed a few things.
Just under 10kg. 6 inch F4 newt with 60mm F4 guide scope, 5x2 inch filter wheel, mini PC and motor focuser.
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Julio Cruz:
Scotty Bishop:
My CEM70G will guide accurately with the built in guider controlled by PhD with me using a 10RC with ApexL and QHY294M Pro. I initially got the mount for the RASA 11 because I didn't think it would guide well for longer focal lengths, but I was pleasantly surprised to be proven wrong on that. The USB 3.0 hub is very nice too.
I don't agree with this at all.. I have issues guiding and they all lead to the iGuider's FL being too little for a C11 Edge FL... even so less with a RASA... I still can't get decent guiding out of mine(1.0 RMS on average) and the mount doesn't center targets even after 3-star aligment... Still struggling with this.. I can't believe ppl are getting .3 RMS with this mount... maybe with a 10lb payload...
I consistantly get .39 to .45 nightly running a payload of 26lbs.
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USB problems: I found the connector to the board had worked loose making performance intermittent. You have to take the Dec saddle apart to access it.
Dec performance: got worse for me so did complete rebalance. I stripped down the Dec assembly to access the worm screw on the left side and adjusted meshing of worm gear. rms dropped from 1.2 down to 0.4 typical.
RA performance was also poor. So I stripped down RA housing to access the worm gear left hand side grub screw - that was loose. Adjusted meshing and rms is also down from 1. 2 to around 0.7 to 0.4.
I have not tried adjusting belt tension yet.
I also now do 3D balancing. Not sure which adjustment made the most difference but now my resolving power is seeing and not mount limited.
Can you please give a brief description of your adjustment of the worm mesh?
The manual shows where the screws are but gives no real direction other than stating not to exceed 1/4 turn, which is kind of useless.
On other mounts, I would tighten until the mount started to bind, then back off a bit. But I’m concerned that the process might be different based on the spring loading mechanism (which is also conveniently not described).
Sorry for the late reply, enjoying sunshine but no dark.
The Cem70 normal process is very similar to other mounts; make small adjustments. Tighten the lock screw and slew. Back-off a little bit if there is binding.
My tracking problem was bigger than typical, very unpredictable and wide swings. There is a set of not user accessible screws for the other end of the worm shaft, they were loose. The result was the worm shaft pivoting more than it should. I suspect it made the thread less perpendicular to the teeth. Adjustments were either binding or too loose with no sweet spot middle.
Next month when I start imaging again I hope to find everything still good.
Is there a document from iOptron on how to access those hidden screws? I have great overall guiding but some spikes in RA and Dec and I am wondering if it might be something like this
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what guiding speed do you use for the CEM70?
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Karl Theberge:
what guiding speed do you use for the CEM70?
Me ? 0.5x
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Uri Abraham:
Hi,
I am about to receive my CEM70G and your post are valuable to me, reading about backlash makes me nervous haha 😂😂
Thanks for your feedback Lorenzo and I will post my comments later on when I experiment with my new mount
If you DEC is out, tighten belt, adjust meshing with Allen keys, change guide rate to 0.90x and you will find it will fix the issue if you have one. I have mine down to 150ms and it guides really well. Make sure you are properly balanced in DEC also, 3D balanced.
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D. Jung:
Got my cem70 a few weeks back and been very happy with it. Guiding performance is great and so much easier to handle than the AVX in every aspect.
Is that Photoshopped? ;-P Only kidding, that is incredible guiding, even if it were a 10Micron mount! Never seen such a tight scatter!
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0.00
7.61
0.00
1.20
0.00
4.37
1.43
2.41
