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iOptron CEM60 unboxing & initial setup.

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#26 Whichwayisnorth

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Posted 19 February 2014 - 11:30 AM

So Michael, the noise you heard during slewing was just the bolt rattling, not the gears, correct?


Correct. And for what it is worth none of the others they've looked at do the same thing. (make any noise at all) So I am asking that they swap this out for another. If they ship today I'll have it tomorrow. I just don't feel like tearing this brand new mount apart to fix it as it would require removing too much. Also for what it is worth only the DEC has this issue. The RA is quiet as a mouse.

It's just the bolt rattling against the casing when the worm is engaged with the wheel. The bolt has no purpose at this point so it just sits there being stupid. I am sure they can come up with a few ideas to isolate it from the casing so it doesn't have a chance to ever vibrate and rattle. Simple fix for the factory. Not so simple for me.

#27 Whichwayisnorth

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Posted 19 February 2014 - 11:34 AM

In your experimentation with the mount, can you see if you can find a way to check how secure that CW shaft mounting mechanism is? I am interested in the mount once it is past beta, but I am uncomfortable with the adjustable counterweight shaft, looks to me like a source of flexure.


Yes I thought of that even before I took it out of the box. As I note in my video, it felt really solid. I see absolutely no cause for concern here at all.

#28 Whichwayisnorth

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Posted 19 February 2014 - 11:48 AM

Exactly right. The CEM60 doesn't use springs as the worm block is held against the main gear via magnets. Really slick btw. The worm then rides smoothly along. I feel there is room to improve the way the knob rests when engaged and I excited to see how things go. iOptron has been very responsive to my feedback so far. :)

Hopefully the clouds will clear, my 11" EdgeHD will arrive this week and I can start doing some actual testing.


Thanks for the review, the mount looks nice.

The clutchless design is nice but you need to be very careful when disengage the worm wheel because it is very easy to damage the worms. I had a ZEQ25 and I didn't like the idea of disengaging the worm wheels just for balancing the mount.

Another issue with this design is that every time you engage/disengage the periodic error profile is modified. I have no clue how the CEM60 is affected by this cause it uses magnets to keep the right tension of the worm.

Cheers,

Jose



My thoughts on this are that since the main gear doesn't move independently of the system when you disengage the worm, it is possible to re-engage the worm in exactly the same position each time. You just need to go back to zero position(home) and make sure you are correctly lined up when you mesh the two back together.

On any of my standard GEM mounts when you release the clutches you are able to physically move the main gear, re-engage the clutch, manually slew back to home, loosen the clutch, move the main gear, re-engage the clutch, slew back to home and so on. So you could use 180 degrees of the main gear one day and the other 180 degrees the other. This would affect the PEC if there were issues with that side of the wheel.

However that being said, most of the PE in mounts comes from the gear box and the worm gear. This mount doesn't seem to have a gear box on the motor and drives a belt directly to the worm. So I don't think there is much PE there. So that leaves the worm. Regardless of where the worm lands you would carry that PE with you. So that then leaves the worm wheel or main gear. As long as you can accurately line up RA when you engage, you *should* have no troubles with the PPEC profile.

I admit it doesn't seem easy since there are no alignment marks to go by. I have to essentially go by sight. Doing that in the dark is going to be fun. I'll probably end up adding my own marks.

I look forward to your thoughts on this. My specific mount has the encoder on the RA which should essentially negate the need for a PPEC profile anyways. However if I can convince iOptron to allow some method of turning the encoder on and off I would love to test and PEC train the mount separately just to see how it is.


On another topic:

One of the things I was thinking about last night was about the raw PE on these mounts. I am curious if the mounts with excellent PE end up being the mounts without the encoder and anything with horrible PE they just thrown the encoder on it to deal with it. I would love to know what my mounts raw PE is without the encoder. I may have to find a pair of wire cutters and get to work!

#29 Whichwayisnorth

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Posted 19 February 2014 - 12:14 PM

I wonder how that impacts the little compass used to find north. Kind of like a dog chasing its tail with the magnets pulling the compass and constantly telling you to turn the mount left till eventually your head explodes from stress. I'm telling you, it's a conspiracy



Compass seems reasonably accurate so far. Personally I use my iPhone and Sky Safari to find polaris and line my mounts up that way. I am not going to complain about having a compass though. It's the little things.


The more I play around with this mount the more I like it. I have all the latest firmware flashed and today, probably this afternoon, I am going to spend some time getting drivers and software set up to use it. I also want to do a speed test on the USB ports, see how many amps each 12v socket provides (there is no manual yet to tell me) and set everything up like I am ready to image for the night and see if I can break something.

:)

#30 Wmacky

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Posted 19 February 2014 - 12:53 PM

Can't remember how you powered the mount up. IF with a battery, CHECK the voltage! It's possible low voltage to the stepper could be causing a non normal vibration.

What do you think?

#31 OzAndrewJ

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Posted 19 February 2014 - 03:39 PM

Gday Whichwayis north

As long as you can accurately line up RA when you engage, you *should* have no troubles with the PPEC profile.



Im a little confused.
A PEC model should not be required if there is an absolute encoder???

Also, if there is a model, unless IOptron have modelled the entire 360deg, it should be irrelevant.
If the PPEC is based on one turn of the worm only, then it doesnt matter if the worm disengages from the wormwheel, esp as the worm will always reset itself to a common position ( based on magnet/spring force ).

Andrew Johansen Melbourne Australia

#32 Peter in Reno

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Posted 19 February 2014 - 03:54 PM

It has stepper motor? How can encoder work with stepper motor? Is the encoder inside the stepper motor? Is it possible to have higher resolution encoder than a single step size of stepper motor? I searched for CEM60 and trying to find out whether this is absolute encoder or a simple ordinary high resolution encoder and cannot find the answer. Anyone else know?

Peter

#33 EFT

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Posted 19 February 2014 - 04:02 PM

It has stepper motor? How can encoder work with stepper motor? Is the encoder inside the stepper motor? Is it possible to have higher resolution encoder than a single step size of stepper motor? I searched for CEM60 and trying to find out whether this is absolute encoder or a simple ordinary high resolution encoder and cannot find the answer. Anyone else know?

Peter


Stepper motors can have encoders just like servo motors. It just that they often don't, but a stepper with an encoder is generally going to be more accurate since the controller can check the movement rather than simply assuming that the correct number of steps were made.

However, in this case, the question is not only what type of encoder is being used (it can't be absolute based on what has already been said), but how and where the encoder is mounted. Is it mounted on the motor, the worm, or the axis shaft. I have not found a spec for this anywhere.

#34 OzAndrewJ

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Posted 19 February 2014 - 04:16 PM

Gday Peter

Is it possible to have higher resolution encoder than a single step size of stepper motor?



Yep.
If the stepper motor has a well designed "microstepping" driver, it can be controlled to well below the default step size of the motor, just takes a bit more power. The main thing is you want an encoder that matches the precision the drive train can achieve, but not much more, as the costs start to go up.
Just need to wait for someone to post a few more details on how it all goes together, to see where the encoder is mounted and what precision it really works to.
Im intrigued by the rattle as well. Sounds just like my EQ6Pro when it starts and stops :grin:

Andrew Johansen Melbourne Australia

#35 Peter in Reno

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Posted 19 February 2014 - 04:21 PM

If it's not absolute encoder, then it must be relative encoder. Nothing special about it and it's very common and nothing wrong with it. Relative encoders are accurate. I just don't like the way dealers advertise this product as "high resolution encoder" or "high end encoder" making almost look like absolute encoder. It's funny that iOptron web site made no mention of "high resolution encoder" for CEM60 and no operating manual is available for download.

Sample dealer ad:

http://www.hampshire...lution-encoders

http://www.optcorp.c...oders-7201.html

Neither of them mention exactly the type of encoder used.

Peter

#36 Whichwayisnorth

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Posted 19 February 2014 - 04:39 PM

I believe there is a plate hidden under the main gear with sensors measuring its position. As this plate is attached directly to the main gear and the main gear is attached directly to the RA I believe it is working well enough. As you may have seen in the video they did supply a printout showing the PE after encoder of about .3 arc seconds pk-pk. The question is how was it measured? Was it measured as a complete system or did they measure it all separately? PEMPRO will tell me soon enough.

Please take this *guess* with a pound of salt. I peaked in through a access hole with a flash light and this is what I think they are doing. Without ripping the mount apart I simply do not know.

#37 Whichwayisnorth

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Posted 19 February 2014 - 05:15 PM

If it's not absolute encoder, then it must be relative encoder. Nothing special about it and it's very common and nothing wrong with it. Relative encoders are accurate. I just don't like the way dealers advertise this product as "high resolution encoder" or "high end encoder" making almost look like absolute encoder. It's funny that iOptron web site made no mention of "high resolution encoder" for CEM60 and no operating manual is available for download.

Sample dealer ad:

http://www.hampshire...lution-encoders

http://www.optcorp.c...oders-7201.html

Neither of them mention exactly the type of encoder used.

Peter


Hopefully iOptron will be forthcoming with the technical data before people spend their money while under the influence of incorrect assumptions.

#38 Whichwayisnorth

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Posted 19 February 2014 - 05:29 PM

If it's not absolute encoder, then it must be relative encoder. Nothing special about it and it's very common and nothing wrong with it. Relative encoders are accurate. I just don't like the way dealers advertise this product as "high resolution encoder" or "high end encoder" making almost look like absolute encoder. It's funny that iOptron web site made no mention of "high resolution encoder" for CEM60 and no operating manual is available for download.

Sample dealer ad:

http://www.hampshire...lution-encoders

http://www.optcorp.c...oders-7201.html

Neither of them mention exactly the type of encoder used.

Peter


As far as I am concerned they can call it a super duper terrifico encoder and it makes zero difference to me. Unless they name it "absolute", which they haven't, then calling it a high-res or high-end is accurate. We know a low res or low end encoder is simply for keeping the position of the RA and DEC when you release clutches and move the mount around. A High-res or High-end encoder is for error correction to the sub arc/second. Which this does.

Based on what I've read I think it is a relative encoder and it senses something attached to the back of the main gear which seems perfectly acceptable to me.

#39 Peter in Reno

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Posted 19 February 2014 - 05:32 PM

FYI. I am not trying to bad mouth iOptron. I prefer to get as much accurate information before purchasing any products.

It's obvious iOptron is trying to be innovative and they appear to be.

Peter

#40 Whichwayisnorth

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Posted 19 February 2014 - 05:44 PM

FYI. I am not trying to bad mouth iOptron. I prefer to get as much accurate information before purchasing any products.

It's obvious iOptron is trying to be innovative and they appear to be.

Peter


Peter,

I didn't take your comment that way at all so no worries :) I think it is important that potential buyers fully understand what they are buying. That is what you were trying to clarify too. What kind of encoders, how and where are they attached and what are they reading from? As you know iOptron as told their testers that they are under NO restrictions. However I also appreciate that iOptron is innovating and releasing a product for review should also be tempered a little.

I am going to self-censor a bit because I can see that iOptron is trying very very hard. They even set up a private FTP server for me to upload videos on every little thing I want to nit-pick about. My job? Make this an exceptional mount that has had every minor little thing addressed before you get yours.

I am going to use and abuse the heck out of it and try to break it. I am going to run every piece of software I can think of to control it. I am going to image at short focal lengths and long ones. I am going to load it to capacity and then some.

And I am going to shoot video the entire time!

Hopefully soon I'll have some solid PEMPRO logs to show and some new videos that I can post.

I want this to be the last mount I buy until I win the lottery.

#41 WesC

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Posted 19 February 2014 - 06:19 PM

Even though I am not personally interested in this mount, I'd like to say what you are doing, and documenting it is much appreciated by everyone. :)

#42 Whichwayisnorth

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Posted 19 February 2014 - 06:34 PM

Even though I am not personally interested in this mount, I'd like to say what you are doing, and documenting it is much appreciated by everyone. :)


I did the same on the LX850. Unfortunately I was also under the heel of a heavy NDA that I was foolish enough to sign.

#43 herrointment

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Posted 19 February 2014 - 06:47 PM

Thanks for doing this!






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