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CEM120 EC2 has arrived.

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#1 JStarCN

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Posted 27 January 2021 - 07:42 AM

Received my new mount today, so looks like the production and delivery schedule is getting back on track.

 

I thought only 1 counter weight was included - that is what the product details said - so I ordered another one.  as it turns out the base order includes 2 counterweights, so I now have 3... Useful as my equipment totals about 30kg.

 

 

 

mount.jpg

 

Also, didn't expect this, but the DIN plugs for the AUX inputs were included (so I don't have to go searching for the right ones, which was proving to be a pain).  That's welcome, although I will have to make up two cables for the plugs and do a bit of soldering).

 

DIN-plugs.jpg

 

I will be updating this thread as I go through each step of set up and get it working.

 

Given some of the issues with the mount reported on this forum, which I have read through in some detail, I will be updating on each of them (like DEC instability) as I test.  The intent is to really get to know this mount before diving in to imaging.  Anyone considering this mount or has it on order, let me know if you have any questions.  If you have this mount and can offer advice, please do.. it will be most appreciated!

 

John

 

...


Edited by JStarCN, 27 January 2021 - 08:03 AM.

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#2 junomike

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Posted 27 January 2021 - 07:50 AM

Beast! 



#3 BobT

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Posted 27 January 2021 - 08:09 AM

John,

 

You'll appreciate having the third counterweight.  My imaging load is about 60 pounds (stacked RC and refractor) and I use all three plus a homebrew 10 pounder.  

 

Keep us informed of your progress.  My CEM120EC is just over 2 years old and is a great performer (on the rare occasion we have clear skies :>).

 

BobT


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#4 JStarCN

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Posted 27 January 2021 - 08:14 AM

Here are the PE Curve measurements that came with the mount:

 

PEC1.jpg

 

pec2.jpg

 

 

Once set up, I'll compare these to what I see unguided in PHD2



#5 alphatripleplus

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Posted 27 January 2021 - 08:41 AM

Good luck with it. Nice to have that extra counterweight.


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#6 JStarCN

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Posted 27 January 2021 - 09:08 AM

Not sure when the change happened, but the mount USB configuration has changed from what I was expecting. Instead of 4 USB2.0 and 1 USB 3.0, the saddle now has 2 USB 2.0 and 3 USB 3.0 - and the 5V output is gone.

 

I'd also heard that there was a problem with fitting the losmandy bar into the saddle (tight).  Didn't have any such issue.  I'll be dual mounting, so the pic below shows one of the saddles in a side direction (just haven't turned the saddle plate yet).

 

One other thing I noticed is that you can not just turn the lock knobs anymore... they have to be pulled out first, then turned.  I think this might be a change from the video's I've seen on this mount (maybe not)... makes it impossible for the lock knobs to be accidentally knocked loose.

 

USB.jpg


Edited by JStarCN, 28 January 2021 - 08:42 AM.

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#7 Creedence

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Posted 27 January 2021 - 09:56 AM

Congratulations on the new mount- it's a beast.  I'll be watching this thread with great interest as I also recently got one, but have yet to see a comprehensive thread both analyzing its performance and outlining the best utilization of the mount.  I have been using mine exclusively unguided, and I am beyond satisfied with its performance- it's been flawless.  I have perfect stars with 5 minute unguided subs at 1100mm focal length.  I plan to start guiding at some point, but hopefully you'll have walked through the nuances of guiding with a 120 before I get to that point.

 

 

Your comment about the about the DIN plugs leads me to believe that your more technically proficient than I am.  Would you mind sharing your cable management setup on the thread when you get to that point?  I'm transitioning away from creatively routing cables to actually using the internal cable runs that the mount provides.  (My approach to astrophotography has been to continuously make small incremental improvements along the way).

 

 

Look forward to following the thread!


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#8 JStarCN

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Posted 27 January 2021 - 10:36 AM

Congratulations on the new mount- it's a beast.  I'll be watching this thread with great interest as I also recently got one, but have yet to see a comprehensive thread both analyzing its performance and outlining the best utilization of the mount.  I have been using mine exclusively unguided, and I am beyond satisfied with its performance- it's been flawless.  I have perfect stars with 5 minute unguided subs at 1100mm focal length.  I plan to start guiding at some point, but hopefully you'll have walked through the nuances of guiding with a 120 before I get to that point.

 

 

Your comment about the about the DIN plugs leads me to believe that your more technically proficient than I am.  Would you mind sharing your cable management setup on the thread when you get to that point?  I'm transitioning away from creatively routing cables to actually using the internal cable runs that the mount provides.  (My approach to astrophotography has been to continuously make small incremental improvements along the way).

 

 

Look forward to following the thread!

Yes, sure... I will be posting that up over the next few days... I have 3 scopes that will be mounted so still need to figure out the optimum use of the through the mount connections.  I suspect I will need some y-splitters for power. 



#9 JStarCN

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Posted 27 January 2021 - 01:27 PM

I had a pier plate made up before my mount arrived (bit of a risk) but has worked out well.

Measurements for the holes which I tapped are good.

I was worried about this.

Pier plate is being spray painted with 'anodized' paint the same red colour as the accents on the mount.

 

pierplate.jpg

 

 

I had a skyshed pier for my previous mount, so I had a single plate made up to replace the top section of the skyshed pier.

The outer holes are also threaded and will bolt down to the skyshed pier lower section with 4 16mm high tensile steel bolts.

This will give me levelling and rotation capability for close north alignment before adjusting the AZ and ALT knobs.


Edited by JStarCN, 27 January 2021 - 01:29 PM.


#10 JStarCN

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Posted 27 January 2021 - 01:44 PM

John,

 

You'll appreciate having the third counterweight.  My imaging load is about 60 pounds (stacked RC and refractor) and I use all three plus a homebrew 10 pounder.  

 

Keep us informed of your progress.  My CEM120EC is just over 2 years old and is a great performer (on the rare occasion we have clear skies :>).

 

BobT

Yet to calculate exactly, but I think the total weight on the mount will be around 30kg (excluding CWs) or 66lbs, so pretty similar, so sounds like I will certainly need the 3 weights.

 

I see you live in Texas... I bet that your rare occasions of clear skies and far less rare than mine - I live in the UK...grin.gif



#11 Tapio

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Posted 27 January 2021 - 01:49 PM

I sure appreciate the twin 12 V DC sockets in the saddle.

But there are two DC sockets in that mount ??



#12 JStarCN

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Posted 27 January 2021 - 02:20 PM

I sure appreciate the twin 12 V DC sockets in the saddle.

But there are two DC sockets in that mount ??

There are 4 12V DC output sockets on the saddle, 2 outputting 5A (good for TEC cameras) and 2 outputting 1A.

 

On the non moving part of the mount there are 2 DC input sockets.

1 to power the mount + the 2 1A sockets on the saddle.

1 to power the 2 5A sockets on the saddle.



#13 astrohamp

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Posted 27 January 2021 - 03:58 PM

I believe the 'mount' power input also supplies USB(2) hub power on my non-EC mount.  Perhaps it does this for both your USB hubs.

 

Hopefully they chose a robust USB3 hub as the new connector set.  An improvement I would think.



#14 benklerk

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Posted 27 January 2021 - 04:23 PM

Hope you enjoy your CEM120EC2. I will never by a Ioptron mount again, I had the CEM120EC for under a year, returned it and got a full refund. I had bad SDE issues on mine, I spent so many months trying to fixing the problem, that I was never able to image with the mount, so with a 14" RC I was not getting round stars. But it seems this problem only effects long focal length telescopes under a certain arc sec resolution. Its been discussed many times on cloudnights.


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#15 JStarCN

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Posted 27 January 2021 - 04:24 PM

I believe the 'mount' power input also supplies USB(2) hub power on my non-EC mount.  Perhaps it does this for both your USB hubs.

 

Hopefully they chose a robust USB3 hub as the new connector set.  An improvement I would think.

Yes, something I will be testing... in the old version with 1 USB 3.0 I had heard that anything cable length more then 25cm from either end caused connection problems/drop outs.



#16 JStarCN

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Posted 27 January 2021 - 04:27 PM

Hope you enjoy your CEM120EC2. I will never by a Ioptron mount again, I had the CEM120EC for under a year, returned it and got a full refund. I had bad SDE issues on mine, I spent so many months trying to fixing the problem, that I was never able to image with the mount, so with a 14" RC I was not getting round stars. But it seems this problem only effects long focal length telescopes under a certain arc sec resolution. Its been discussed many times on cloudnights.

Yes, I have seen all the discussions - read through every single thread end to end - so my eyes are wide open.

I will be testing for most, if not all, of those issues.

One of my scopes is 2.35m focal length which will occasionally be used for deep sky imaging (but mostly planets).

My other two scopes being mounted are FL's of 335 and 600.

 

Once I have checked and loaded the newest firmware, the first thing I will testing tomorrow is for any slewing squeaks, crunches or clicks.

 

There looks to be a clear(ish) night (5% cloud) on Saturday night - so that is currently earmarked for testing for SDE - if I am confident I have set everything up correctly.

I have no problem ironing out any issues, as long as they are fixable.


Edited by JStarCN, 27 January 2021 - 04:38 PM.


#17 RossW

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Posted 27 January 2021 - 07:47 PM

Here are the PE Curve measurements that came with the mount:

 

 

Once set up, I'll compare these to what I see unguided in PHD2

Don't believe the supplied PE curves. Your mount could easily have terrible SDE and the supplied PE curves will not show it. And I am yet to hear of a single confirmed case of iOptron being able to fix a mount with high SDE. If you're imaging at short to mid focal lengths your mount can have out-of-spec SDE and you may not realise it. I'm talking about a 2 to 4 arc-sec peak-to-peak constant oscillation of 3.3s period (for the CEM120EC/EC2), so it is too fast to guide out and will give you slightly oblong stars when imaging at long focal lengths (at small/fine pixel scales).

 

I recommend one of your first tests should be to measure your mount's SDE, which is best performed at long focal lengths. The test is easy to do:

  1. Get a good PA and calibrate the guider (preferably PhD).
  2. Slew to a very bright star, say, mag 1 or brighter, preferably near zenith so that you can measure the SDE's full amplitude rather than cos(Dec) * SDE amplitude.
  3. Turn off guiding (turn off the "Enable mount guide output" setting in the brain of PhD) to avoid instability problems due to rapid-fire guide pulses (see next step)
  4. Reduce guiding exposure rate to around half a second or faster (I've tried 0.1 to 0.5 seconds successfully). 
  5. Set your guider to download image subframes rather than full frames (look in the camera tab in the "brain" of PhD). This is important to achieve a high enough sample rate to measure the SDE. Make sure PhD is not losing the guide star at this fast rate of sampling; it is best to turn off the "star mass detection" setting in PhD;
  6. Let the EC2 track for around 20 minutes while PhD logs star displacement data.
  7. Post the PhD logs here to CN for analysis.

If your mount's SDE is out of spec, send it back to your dealer within the return period. Insist on a replacement or refund, not a repair

 

You can read about my EC2's problems here (I'm yet to write a sequel to the saga though):

 

https://www.cloudyni...lity/?p=9284359

 

On a more positive note, if your EC2 has in-spec SDE you'll probably find it is a fantastic mount and worth the price you paid. My original EC2's problem could not be resolved and it took a Herculean effort to get iOptron to replace it (a sheer hell that I hope no other owner has to go through). I eventually received a replacement mount with minimal SDE (around 0.3 arc-sec RMS from memory), and it's performance as a guided mount is marvelous and approaches that of much more expensive "premium" mounts.

 

Cheers,

 

Ross


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#18 OzAndrewJ

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Posted 27 January 2021 - 08:48 PM

Gday JStarCN

 

What Ross has said covers pretty much all there is.

You need moderately high frame rate data, ( 0.5s frame rate will be good enough )

and a small arcsec/pix resolution ( dont worry re oversampling theories )

to get the SDE if there.

As an alternative to "guider apps" ( i have problems getting a high frame rate ( true rate on disk vs camera rate )

another user has developed an app that can take a short *.ser format file and create centroids from it.

Depending on the app used to run the camera ( i use firecapture ),

you can easily grab very high frame rates, and the ser format saves raw data for good centroids.

Some users are getting very clean data at 110fps when testing for microstepping errors

but the process would work just as well for SDE.

Based on a 3.3s period, you would want to grab at least one minutes worth of data at say 10fps or better

to get a good analysis.

Andrew Johansen Melbourne Australia


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#19 Jgronseth

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Posted 27 January 2021 - 09:10 PM

Gday JStarCN

What Ross has said covers pretty much all there is.
You need moderately high frame rate data, ( 0.5s frame rate will be good enough )
and a small arcsec/pix resolution ( dont worry re oversampling theories )
to get the SDE if there.
As an alternative to "guider apps" ( i have problems getting a high frame rate ( true rate on disk vs camera rate )
another user has developed an app that can take a short *.ser format file and create centroids from it.
Depending on the app used to run the camera ( i use firecapture ),
you can easily grab very high frame rates, and the ser format saves raw data for good centroids.
Some users are getting very clean data at 110fps when testing for microstepping errors
but the process would work just as well for SDE.
Based on a 3.3s period, you would want to grab at least one minutes worth of data at say 10fps or better
to get a good analysis.
Andrew Johansen Melbourne Australia


Yep, Andrew is referring to an app I wrote. Users were successful capturing video in SER format of a star using Firecapture and Sharpcap. My app will take the video and produce a text file containing timestamp and centroid information for each frame. Then Andrew can take the centroid file and plug it into his app for a complete analysis. If you have any SDE issues, his app will definitely show it.

James
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#20 JStarCN

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Posted 28 January 2021 - 05:30 AM

^good advice above..

Thank you Ross, Andrew, James.

 

Will run through and post logs here once I am set up and get a clear night - as I said, hopefully Saturday.

 

John



#21 chanrobi

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Posted 28 January 2021 - 09:53 AM

Don't believe the supplied PE curves. Your mount could easily have terrible SDE and the supplied PE curves will not show it. And I am yet to hear of a single confirmed case of iOptron being able to fix a mount with high SDE. If you're imaging at short to mid focal lengths your mount can have out-of-spec SDE and you may not realise it. I'm talking about a 2 to 4 arc-sec peak-to-peak constant oscillation of 3.3s period (for the CEM120EC/EC2), so it is too fast to guide out and will give you slightly oblong stars when imaging at long focal lengths (at small/fine pixel scales).

 

I recommend one of your first tests should be to measure your mount's SDE, which is best performed at long focal lengths. The test is easy to do:

  1. Get a good PA and calibrate the guider (preferably PhD).
  2. Slew to a very bright star, say, mag 1 or brighter, preferably near zenith so that you can measure the SDE's full amplitude rather than cos(Dec) * SDE amplitude.
  3. Turn off guiding (turn off the "Enable mount guide output" setting in the brain of PhD) to avoid instability problems due to rapid-fire guide pulses (see next step)
  4. Reduce guiding exposure rate to around half a second or faster (I've tried 0.1 to 0.5 seconds successfully). 
  5. Set your guider to download image subframes rather than full frames (look in the camera tab in the "brain" of PhD). This is important to achieve a high enough sample rate to measure the SDE. Make sure PhD is not losing the guide star at this fast rate of sampling; it is best to turn off the "star mass detection" setting in PhD;
  6. Let the EC2 track for around 20 minutes while PhD logs star displacement data.
  7. Post the PhD logs here to CN for analysis.

If your mount's SDE is out of spec, send it back to your dealer within the return period. Insist on a replacement or refund, not a repair

 

You can read about my EC2's problems here (I'm yet to write a sequel to the saga though):

 

https://www.cloudyni...lity/?p=9284359

 

On a more positive note, if your EC2 has in-spec SDE you'll probably find it is a fantastic mount and worth the price you paid. My original EC2's problem could not be resolved and it took a Herculean effort to get iOptron to replace it (a sheer hell that I hope no other owner has to go through). I eventually received a replacement mount with minimal SDE (around 0.3 arc-sec RMS from memory), and it's performance as a guided mount is marvelous and approaches that of much more expensive "premium" mounts.

 

Cheers,

 

Ross

What is SDE



#22 JStarCN

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Posted 28 January 2021 - 11:31 AM

The ipolar camera has now been fitted.

It's quite a bit different to fitting the polemaster.

 

Followed these instructions - sort of:

http://www.ioptron.c...339A-CEM120.pdf

 

However, I ignored the step to remove the balance bar housing - that seems wholly unnecessary.  The iPolar slots into the hole fine without removing the housing (and one of the bolts holding the housing on was so 'locked' I would have had to use excessive force to remove it anyway).

 

The install looks a lot cleaner than the Polemaster.

 

ipolar.jpg

 

The cap also screws on fine.

 

One other thing - I don't think the Polemaster will even work anymore as the connections have changed.

No longer a USB connection at either side - it's a 4pin wire.


Edited by JStarCN, 28 January 2021 - 11:36 AM.

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#23 Tapio

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Posted 28 January 2021 - 12:15 PM

What is SDE

Sub-divisional error.



#24 JStarCN

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Posted 28 January 2021 - 01:08 PM

FIRST ISSUE:

 

Comes before I expected to find one to be honest.

 

The gear locking knob does not fully engage on the RA axis... sounds very off when trying to engage it and will not turn completely to the locked position.

The problem with this one is that it could be a major issue and precludes any progress.  I dare not switch the mount on with what appears to be a half locked gear and I don't want to force the switch either.

 

Unless there was no QC check on this at all, I guess there could have been transit damage, but I did check the position of all knobs and they were correct on arrival. Gears disengaged, locks on.

 

For now, that concludes any testing and so begins my discussions with ioptron support.

frown.gif

 

EDIT : resolved - iOptron support were super quick in suggesting a fix that worked.


Edited by JStarCN, 28 January 2021 - 06:09 PM.


#25 JStarCN

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Posted 28 January 2021 - 01:31 PM

ISSUE 2:

The counterweight bar holder is machined so poorly that the counterweight bar will not thread into it.

That's an odd one.

 

EDIT : see later in thread.. this was my issue.. RA is supposed to be rotated 90 degrees before screwing the counterweight bar in.


Edited by JStarCN, 28 January 2021 - 06:07 PM.



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