iOptron CEM40 vs the new CEM40EC (EC)

[whatthedragon]

Does anyone know what the EC stands for and why it's 1k + more  in the whole iOptron line of mounts? \

In fact I think I have seen the EC on the title of other companies as well and they are more $$ too

CEM40

https://www.ioptron.com/product-p/c401a1.htm

vs

CEM40EC

https://www.ioptron.com/product-p/c404a1.htm

 

[whatthedragon]

another example .

RST-135

http://www.rainbowastro.com/rst-135/

vs

RST-135E

http://www.rainbowastro.com/rst-135e-feature-eng/

 

[Ratlet]

I believe the EC mounts have encoders.  Complete novice, but my understanding is that it lets the mount remember where you were even if you move it by disengaging the clutches.

[Same old newbie alert]

EC means encoders... Some have encoders on just the Ra, others at a much higher cost can be on both axis... Ioptron have EC versions on most of the range they sell

[Dr Strange]

EC means encoders. Don't believe the hype surrounding the iOptrion encoders. They are rubbish. There is a reason why the 10 Micron and Astro Physics mounts with encoders cost so much. The actual encoders are high quality and the software is well done.

iOption has been trying for literally years to solve the SDE* problem that is very bad in the encoders they use. At short focal lengths the mount does fairly well and the problem is masked but at longer focal lengths the high frequency harmonic that occurs because of the SDE corrections attempted  leads to potato stars in the images. In addition, when last I checked, you cannot turn off the encoders to stop this problem from happening. In addition the mounts can be hit or miss in terms of mechanical quality. You may be lucky and get a good one, or you may draw the short straw in the a***hole lottery and get a rubbish one...

 

 

* https://www.linearmotiontips.com/what-is-sub-divisional-error-sde-in-linear-encoders/

Edited April 14, 2022 by Dr Strange

[whatthedragon]

I did hear back from two people at iOptron Corporation,

The EC represents our mounts that have a high resolution encoder that
monitors and adjusts the mounts tracking rate. This system delivers the
highest tracking accuracy to the point where guiding is no longer necessary.
 

and 

EC indicates that the mount has an high precision optical encoder system on
RA axis which will provide PE<0.25 arcsec rms. As a comparison, the standard
version has a PE of <14 arcsec pp.

 

[whatthedragon]

I currently own there cheaper CEM26 and it works pretty well. I am shooting wide field. I was looking into getting a new mount that can handle a higher payload. Any Suggestions as what you use ?

 

[whatthedragon]

On 14/04/2022 at 12:05, Dr Strange said:

You may be lucky and get a good one, or you may draw the short straw in the a***hole lottery and get a rubbish one...

lets say I grab one of these new mounts, what can I do to measure the amount of SDE error, is there some kind of written test I could do in a more controlled environment (in-doors) or just use it and if it works great > leave it at that?