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Upgrading mount... iOptron CEM120

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103 replies to this topic

#51 Skymind

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Posted 27 January 2019 - 09:16 AM

After aligning  on three stars, did a go-to to M42. Decided to be crazy and do a 300 sec exp. on m42. After slewing and centering, started the exposure, and after a few seconds there was a clicking noise every 2 seconds, on the RA. Waited, looked at the exposure, there were long star trails. This 2 second clicking was repeated after turning the RA encoder to on. The star trails were horible, the 2 second  repeating clicking noise is still there.

    When that issue is figured out, WOW, 5 STAR Rating. 

    Any ideas?

Have you tried other targets at different altitude? 



#52 gotak

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Posted 27 January 2019 - 11:08 AM

Just had our first night out with the newley arrived CEM120EC...Replaced the CGEMPRO. It was a dark, clear night and the anticipation was high!
After pushing the On button, for the first time, the HC started out with weird messages about main board disconnects, faults etc...but after numerous reboots it seemed to change its mind.
Everything seems to be coming up to speed.
The GPS did it’s job, the times and other data corrected, the zero position confirmed, proceeded to a three star alignment, which was a rather nice experience.
After selecting the onboard WiFi, it connected with the IPAD running SKYSAFARI 6 pro, mount control was fine.
Balance was better than any other mount we have had in the 10 year old observatory. Heck, with 42 lbs of equipment, buttery smooth.
Still working on getting the HC serial to usb cable connecting the mount thru the HC serial cable, then to the ASIAIR to wirelessly connect to SkySafari 6 pro, repeated connection failure there. Perhaps some confusion with on board WiFi, which was disconnected.
Now for the BIG issue!
After aligning on three stars, did a go-to to M42. Decided to be crazy and do a 300 sec exp. on m42. After slewing and centering, started the exposure, and after a few seconds there was a clicking noise every 2 seconds, on the RA. Waited, looked at the exposure, there were long star trails. This 2 second clicking was repeated after turning the RA encoder to on. The star trails were horible, the 2 second repeating clicking noise is still there.
When that issue is figured out, WOW, 5 STAR Rating.
Any ideas?


Hard to say anything from the limited information provided.

Can we see one video of the clinking?

#53 ScottS

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Posted 27 January 2019 - 01:53 PM

Just an update from my original post about upgrading...  I still have not pulled the trigger.  Here is Columbus it has been cloudy about ever night since the first part of December.  I think we have had a total of 9 clear nights. 

 

But anyway "gotak" the only time I've ever experienced "click" was doe to not having proper balance.  This has been the case with my last two setups.  I've not yet had a iOptron in my hands but you might want to look at your balance setup.  Hope you can get your issue solved!



#54 rgsalinger

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Posted 27 January 2019 - 02:42 PM

I would not be trying to do so much in one night. I know that I could never get everything working (including wireless networking) in one night. So, my advice is to start by seeing if the mount basically works.  My 120EC2 wouldn't even connect to my computer until I got all of the correct firmware and drivers installed. I think that a more incremental approach is the only way to correctly locate your issue with tracking.

 

First, you should download and install the lastest firmware and drivers for the mount and, if using ASCOM, also the latest version of ASCOM. Check balance and that the worms are fully engaged.Then run the encoder calibration routine and the find zero routine. Reboot the system and allow the GPS to do it's job. Once you get the GPS OK message, then check computer connectivity and then disconnect. Then run a three star calibration with a reticle eyepiece. Check everywhere to see that you are not at the meridian and/or that limits have been set somewhere in the software stack. That's why I suggest not connecting a computer at this point. Now you should be able to track any object with an eyepiece.

 

If that works then the mount is OK. If the object moves then the PA is most likely the culprit. If you get a stall, then the mount needs to go back (IMHO) and be replaced or fixed. 

 

Once you ascertain that the mount is OK then incrementally add things on, one at a time until you can fully debug any problems. My guess is that there are limits set "somewhere" and or that you (as I have done too many times in the past) started tracking right at the meridian without realizing it. 

 

Rgrds-Ross


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#55 DuncanM

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Posted 30 January 2019 - 05:18 PM

Mount arrived yesterday and the CWs and CW shaft today.

 

I just got the mount balanced on my pier (10in SCT, 2 x finders, JMI crayford,NEG,  SSProV2 = ~35lb) with 2 x 22lb CWs (one at the top of the CW shaft).  Balancing was extremely straightforward.

 

Just upgraded the firmware...USB is nice!

 

Some impressions...

 

Compared to the CGE PRO the CEM120 is positively svelte...almost disappointing grin.gif

 

The gear switches and shaft locks are nice and well thought out.

 

The dovetail plate is huge and my 10in SCT only uses the top two locking screws.


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#56 brinke

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Posted 31 January 2019 - 12:28 AM

Hello everybody! After two weeks using CEM120EC I had my first problem: during regular observation the mount suddenly start to move fast without a real target. Does any one experienced the same problem?

Mount is corrently connected to a computer using PHD2 guide. I also use SECOM software to see the mount in Stellarium.

Another issue: the first night with the mount was crazy good for the EC but had problem with PHD2 to make the tracking. FOR THIS REASON I TRIED TO ALIGN BETTER THE MOINT TO THE POLE (as I can’t see Polaris) using the polar iterate align but actually seems that this procedure take me really out of the pole as I had worst results even with the encoder which now don’t track well. I also have to say that the second night I accidentally hit the counter bar with my body and at that time the mount started to make big noise and move suddenly without any possibility to stop it. I had to turn off power and restart it then the mount was moving normally without noise.

Please inform me if anybody had similar experiences
And if solves them.

What you use for polar alignment?


Inviato dal mio iPhone utilizzando Tapatalk

#57 gotak

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Posted 31 January 2019 - 08:58 AM

I am only aware of one person having issues with strange slews resuming form parked, other folks seems to use parking without issue so no one's sure what the cause is for that user.

 

In your case maybe there's some interaction with Stellarium? If you try a regular hand controller or direct ASCOM slew (like with SGP for example) does it still do the same unexpected moves?

 

Their polar iterate alignment is utter BS. It doesn't compensate for cone error so only works if your OTA is somehow magically perfectly aligned with your mount. Otherwise all it does is give you a nice wild goose chase. When you ask iOptron about it the best they could come up with is not to put the star in the center when you use the iterate alignment, which is about as useful as getting your world view from twitter.

 

If you can't see polaris I am afraid the only solution is to use drift alignment. 


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#58 rgsalinger

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Posted 31 January 2019 - 12:21 PM

1. I use the SKYX or PEMPRO for polar alignment on my CEM120EC2 as I cannot see the pole. I really like PEMPRO. While it costs some money, you don't ever need to see Polaris and the wizard is easy to use. You can also use it to create a PEC curve if you have a mount without encoders. I bought my copy 5 years ago and it still works.

 

2. I have never had a runaway slew. I would wonder about the software you are using more than anything else. Remember, just one click of the mouse when you are pointing to something on the screen can, if you don't have "confirm slews" turned on send the mount off on a slew.

 

3. I keep the hand controller disconnected for much the same reason. It's just something that can short out and cause problems. 

 

4. Everynight a do a find zero. My mount is parked pointing at Polaris. It moves a little. I then do a trial slew. If the object is in my FOV then I'm good for the night. If it's not then I do a pointing model which takes about 15 minutes to do 20 points.

 

5. I don't use the GPS. My computer keeps the time accurately enought that it's never been an issue. I have an internet connection and I just update the time on the PC and then push the PC time to the mount. 

 

6. Unfortunately I don't use either PHD or Stellarium - I use MaximDL or the SKYX to image. I have always been afraid of bugs in freeware products and I know that no one tests them in an integrated manner with each mount that comes out. 

 

7. Make sure that you have the latest motor and mainboard software up and running. The early versions did have bugs but the one's from June of 2018 onward have been robust for me.

 

Rgrds-Ross


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#59 DuncanM

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Posted 31 January 2019 - 02:26 PM

Mount arrived yesterday and the CWs and CW shaft today.

 

I just got the mount balanced on my pier (10in SCT, 2 x finders, JMI crayford,NEG,  SSProV2 = ~35lb) with 2 x 22lb CWs (one at the top of the CW shaft).  Balancing was extremely straightforward.

 

Just upgraded the firmware...USB is nice!

 

Some impressions...

 

Compared to the CGE PRO the CEM120 is positively svelte...almost disappointing grin.gif

 

The gear switches and shaft locks are nice and well thought out.

 

The dovetail plate is huge and my 10in SCT only uses the top two locking screws.

The weather here has been cloudy almost constantly...the new mount blues...bawling.gif

 

It did clear up about an hour before sunrise, and I was able to PA the mount using Sharpcap. The PA alt/az controls are very smooth and PA was easy once I got going, but I had no time to test PA accuracy (Sharpcap reported  ~15 arc seconds)  nor even do another Sharpcap run, as I attempted to test the PE and drift but then ran out of darkness and had to pack it in.



#60 HxPI

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Posted 31 January 2019 - 05:30 PM

The weather here has been cloudy almost constantly...the new mount blues...bawling.gif

 

It did clear up about an hour before sunrise, and I was able to PA the mount using Sharpcap. The PA alt/az controls are very smooth and PA was easy once I got going, but I had no time to test PA accuracy (Sharpcap reported  ~15 arc seconds)  nor even do another Sharpcap run, as I attempted to test the PE and drift but then ran out of darkness and had to pack it in.

 

Did you have refraction compensation in Sharpcap setup? Curious about how much impact this would have on tracking performance. I am having tracking issues with my CEM60EC and want to try and see if polar alignment with refraction compensation will help. May have to do a drift alignment to get to ground truth. Bad weather hasn’t helped!

 

Thanks for sharing.

 

Ciao,

Mel


Edited by HxPI, 31 January 2019 - 05:31 PM.


#61 DuncanM

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Posted 01 February 2019 - 12:58 AM

Did you have refraction compensation in Sharpcap setup? Curious about how much impact this would have on tracking performance. I am having tracking issues with my CEM60EC and want to try and see if polar alignment with refraction compensation will help. May have to do a drift alignment to get to ground truth. Bad weather hasn’t helped!

 

Thanks for sharing.

 

Ciao,

Mel

I'm using an older version of Sharpcap that doesn't have refraction compensation built in and at 31.9 degrees N (4500ft)  altitude, refraction is a bit of an issue and will probably induce a small error (~1.7 arc minutes) except when I am imaging objects at similar altitudes - there's always some debate over whether to use the true or refracted pole altitude.  I hope to try some tracking and PE tests in the next few days, weather permitting.


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#62 HxPI

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Posted 01 February 2019 - 12:50 PM

I'm using an older version of Sharpcap that doesn't have refraction compensation built in and at 31.9 degrees N (4500ft)  altitude, refraction is a bit of an issue and will probably induce a small error (~1.7 arc minutes) except when I am imaging objects at similar altitudes - there's always some debate over whether to use the true or refracted pole altitude.  I hope to try some tracking and PE tests in the next few days, weather permitting.

Thanks for the response.



#63 rgsalinger

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Posted 01 February 2019 - 08:05 PM

If you know the angle of polaris at your site and you want to use the true pole and not the refracted pole for some reason, then just align to the refracted pole and then move the scope to what you think is the correct location. I use PEMPRO and the SKYX for polar alignment and both of them align to the refracted pole which is around 80 arc seconds (at my latitude) off the true celestial pole. So, I'm not sure that there's much to be gained by trying to get closer than 1 arc minute. The only use case I can think of would be very long unguided exposures. People make too much of polar alignment accuracy and there's no way that a tool like sharpcap used with a guide scope is going to truly get you within 1 arc minute.

Rgrds-Ross



#64 HxPI

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Posted 01 February 2019 - 09:28 PM

If you know the angle of polaris at your site and you want to use the true pole and not the refracted pole for some reason, then just align to the refracted pole and then move the scope to what you think is the correct location. I use PEMPRO and the SKYX for polar alignment and both of them align to the refracted pole which is around 80 arc seconds (at my latitude) off the true celestial pole. So, I'm not sure that there's much to be gained by trying to get closer than 1 arc minute. The only use case I can think of would be very long unguided exposures. People make too much of polar alignment accuracy and there's no way that a tool like sharpcap used with a guide scope is going to truly get you within 1 arc minute.

Rgrds-Ross

I agree with the limitations of using SharpCap polar alignment for anything beyond 1 arcmin accuracy. If polar alignment is within 1 arcmin, then mount tracking should be good unguided for at least how long? I would think 30 seconds at least but maybe not in certain parts of the sky. My personal experience has shown a wide range from a few seconds to a few minutes, depending on how “well” my mount is setup and performing at a given moment. This is what I’m trying to figure out so I have a realistic expectation on how well my mount is performing. I don’t get out much so figuring this out has been difficult.

 

I like unguided tracking for EAA; it’s quite convenient to just have the mount goto and track for enough time to stack images in SharpCap. When it works, it’s wonderfully simple and a joy to operate. Most of the time however the unguided tracking is not good enough for my optical system to live stack well, if at all. So then I have to figure out and setup a guided system. Not as convenient but more resilient to tracking issues.

 

Thanks for sharing.

 

Ciao,

Mel


Edited by HxPI, 01 February 2019 - 09:36 PM.


#65 rgsalinger

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Posted 01 February 2019 - 10:07 PM

The difficulty in doing unguided imaging is not simply getting good polar alignment. You also need to have a mount with very low PE. Finally, the environment - wind, vibration - also have to be controlled. And, most successful unguided long images require a mount model as well. To me it's chasing your tail unless you have the right equipment. By the time you have the right equipment guiding is trivial. I'm sure that someone out there disagrees. I can only speak to theory and my own experience. As a matter of choice, I measure things in PI or MaximDL to determine the quality of my raw data. I know that skilled processors can do tons of things that I can't do with the same data. 


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#66 HxPI

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Posted 01 February 2019 - 10:30 PM

The difficulty in doing unguided imaging is not simply getting good polar alignment. You also need to have a mount with very low PE. Finally, the environment - wind, vibration - also have to be controlled. And, most successful unguided long images require a mount model as well. To me it's chasing your tail unless you have the right equipment. By the time you have the right equipment guiding is trivial. I'm sure that someone out there disagrees. I can only speak to theory and my own experience. As a matter of choice, I measure things in PI or MaximDL to determine the quality of my raw data. I know that skilled processors can do tons of things that I can't do with the same data. 

I don’t think 30 seconds unguided tracking accuracy with 952mm f/l refractor is too much to ask for the CEM60 or the CEM120!

 

Thanks for sharing.

 

Ciao,

Mel


Edited by HxPI, 01 February 2019 - 10:40 PM.


#67 rgsalinger

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Posted 02 February 2019 - 12:24 AM

Sure, my CEM120 easily did 5 minutes unguided a few months back with a 660mm 5" refractor. I must have misread your post.

Rgrds-Ross



#68 WadeH237

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Posted 02 February 2019 - 09:12 AM

The difficulty in doing unguided imaging is not simply getting good polar alignment. You also need to have a mount with very low PE. Finally, the environment - wind, vibration - also have to be controlled. And, most successful unguided long images require a mount model as well. To me it's chasing your tail unless you have the right equipment. By the time you have the right equipment guiding is trivial. I'm sure that someone out there disagrees. I can only speak to theory and my own experience. As a matter of choice, I measure things in PI or MaximDL to determine the quality of my raw data. I know that skilled processors can do tons of things that I can't do with the same data. 

I think that this is spot on.

 

And I'll toss in that if you are imaging anywhere other than near the zenith, and you are using a small imaging scale, you need tracking rate correction and a sky model.

 

Guiding is *much* easier than getting reliable unguided tracking for anything other than wide field or short duration exposures.


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#69 DuncanM

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Posted 02 February 2019 - 05:29 PM

The weather here has been cloudy almost constantly...the new mount blues...bawling.gif

 

It did clear up about an hour before sunrise, and I was able to PA the mount using Sharpcap. The PA alt/az controls are very smooth and PA was easy once I got going, but I had no time to test PA accuracy (Sharpcap reported  ~15 arc seconds)  nor even do another Sharpcap run, as I attempted to test the PE and drift but then ran out of darkness and had to pack it in.

So...I ran a PE and Dec backlash test last night. PE was about 7.7 arc secs/PtoV (  the included readout was 6arcsecs/PtoV) which is a bit out of spec. However PHD reported quite a bit of backlash in Dec and I noted that the gear mesh in both axis was a bit loose. I tightened both with no deleterious effects on slewing and will retest ASAP. By feel the Dec backlash seems gone.


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#70 skycamper

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Posted 04 February 2019 - 11:54 AM

I'm seriously considering the Cem120 as an alternative to an AP or SB mount.  Is backlash adjustments on this mount difficult to do? That's why I liked the self adjusting gears on the AP mount because I'm afraid that mine won't be within spec. Which leads me to my next question if I have to send this mount back for service where is it going and how hard is that Based on people's experiences ? One other problem for me is that the mount is tough to look at. It's just so different from a regular EQ. I'm hoping it might grow on me.



#71 Corwinmageoin

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Posted 04 February 2019 - 03:10 PM

I am stacking up my pennies to get the EC2.  Is there anyone in the CEM120 group that could send me an invite?  I would like to keep learning in the interim.



#72 gotak

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Posted 04 February 2019 - 05:37 PM

I'm seriously considering the Cem120 as an alternative to an AP or SB mount. Is backlash adjustments on this mount difficult to do? That's why I liked the self adjusting gears on the AP mount because I'm afraid that mine won't be within spec. Which leads me to my next question if I have to send this mount back for service where is it going and how hard is that Based on people's experiences ? One other problem for me is that the mount is tough to look at. It's just so different from a regular EQ. I'm hoping it might grow on me.


There is only a belt, worm and wheel. The only backlash adjustments is how the wheel and worm meets, an dmaybe the belt tension.

Adjustments is prettt easy with ioptron mounts.

The worm is held to the wheel by magnetic force. Im theory there is no need to adjust it. I haven't seen anyone needing to do that just yet.

Sometime you find the end caps for the worm needs looking at in other ioptron mounts, bur again it's not a difficult process.
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#73 DuncanM

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Posted 04 February 2019 - 11:45 PM

So...I ran a PE and Dec backlash test last night. PE was about 7.7 arc secs/PtoV (  the included readout was 6arcsecs/PtoV) which is a bit out of spec. However PHD reported quite a bit of backlash in Dec and I noted that the gear mesh in both axis was a bit loose. I tightened both with no deleterious effects on slewing and will retest ASAP. By feel the Dec backlash seems gone.

I had entered the focal length of the guidescope incorrectly into PHD2 (entered 180mm instead of 210mm) so the actual error was almost exactly 6 arc seconds according to PEMpro (same as iOptron reported) and the error curve was almost identical to the included print-out from iOptron.

 

After I adjusted the RA gear switch meshing adjustment Pempro reports 4.82 arcsecs PE/PtoV. However doing the same for  Dec didn't reduce the reported backlash.



#74 gotak

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Posted 05 February 2019 - 12:11 AM

I had entered the focal length of the guidescope incorrectly into PHD2 (entered 180mm instead of 210mm) so the actual error was almost exactly 6 arc seconds according to PEMpro (same as iOptron reported) and the error curve was almost identical to the included print-out from iOptron.

 

After I adjusted the RA gear switch meshing adjustment Pempro reports 4.82 arcsecs PE/PtoV. However doing the same for  Dec didn't reduce the reported backlash.

Do note that some folks have found that PHD's backlash measurement is a bit dodgy.

 

The real way to get proper backlash is to see how much BL comp it actually has to dial in during real guiding. It might be you find that it is actually a very slight amount that makes it unnecessary to use compensation.



#75 Skymind

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Posted 05 February 2019 - 08:07 AM

I had entered the focal length of the guidescope incorrectly into PHD2 (entered 180mm instead of 210mm) so the actual error was almost exactly 6 arc seconds according to PEMpro (same as iOptron reported) and the error curve was almost identical to the included print-out from iOptron.

 

After I adjusted the RA gear switch meshing adjustment Pempro reports 4.82 arcsecs PE/PtoV. However doing the same for  Dec didn't reduce the reported backlash.

So iOptron PE curve matches field test result, maybe they also use PEMPro. When you reduced the PE from 6" to 4.82" did the curve keep the same shape or change?

Congrats your much better than spec copy. 




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