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Equipment Discussions >> Mounts

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DesertCrawler
member
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions new [Re: Hermie]
      #6144581 - 10/18/13 10:29 AM

I am trying to image with a C9.25. I had the same issues as Heinz and resolved them on my own with some guidance by iOptron, basically using the methods mentioned in this thread, albeit before this thread had evolved to that point. In other words, I climbed this curve. I am now at a point where 60-90 unguided subs are achievable.

Here's what I have learned:

The mount may require a few rounds of tuning. Mine has been disassembled no fewer than three times in order to get it tuned to where it was usable to a critical observer, and I may take one more crack at it because there may be just a little more performance to be found.

Correct balance is critical. It took some time to determine what that was for the specific visual chain in use, but once achieved, many issues resolve. I use weights to coerce the center of gravity more to the center of the OTA so that everything stays more balanced as it slews.

The springs can be had from iOptron. Mine were sent free of charge. I believe the spring issue is a defect with the product, and got the impression iOptron believed the same thing. I would suggest people ask them for the correct springs.

I used to suspect the payload specification was optimistic. I have somewhat changed my mind since it now easily handles about 23 pounds of gear and imaging to boot. What I now believe is the mount suffers from poor quality control. The good thing is the mount is also backed by a company that appears to really support the product. Once tuned, the mount is a very good performer.

Hopefully future versions are better assembled. I would not expect most people to have the patience nor the skills or desire to learn how to rebuild what is sensitive instrument immediately after a non-trivial monetary outlay. The mount is not sold as a kit so it should work correctly out of the box. iOptron really needs to get this right.

Fortunately, they have some very dedicated support people here in the US.


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Astronewb
scholastic sledgehammer
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Reged: 09/19/11

Loc: Connecticut
Re: iOptron ZEQ25, initial impressions new [Re: Hermie]
      #6144598 - 10/18/13 10:41 AM

The slightest touch causes vibrations which need up to 5 seconds to die down. I can't touch the eyepiece but have to hover above it while looking through it.

Quote:

That sounds rather annoying Heinz. I don't use the mount for visual at all, but only for AP. I've never had a diagonal in any of my otas for over a year.




Focusing with a Dslr with a Bahtinov mask, with live view at maximum zoom, I can't detect any vibrations?

When you balance the Z, try balancing with the ota a bit heavy to the front of the tube in DEC, and a bit heavy to the ota in RA. That should reduce the vibrations you are getting by using the mass of the ota as a damper.

That's how I set up my mount for imaging. If the mount were perfectly balanced every slightest breeze would have the mount oscillating I imagine?

The other suggestions users have mentioned are good ones also.

Try it, couldn't hurt?

Best...Paul


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pippo
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Reged: 01/12/13

Loc: Paris (FR), Pantelleria (IT)
Re: iOptron ZEQ25, initial impressions new [Re: Astronewb]
      #6144750 - 10/18/13 12:05 PM

Dear DesertCrawler,
could you tell us the specifications (length at rest, length at maximum compression, diameter of the wires,...) of the new spring sent to you by iOptron.

Thanks


Francesco

Francesco


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Bluejay08
member


Reged: 09/29/09

Re: iOptron ZEQ25, initial impressions new [Re: Ryuno]
      #6145258 - 10/18/13 05:12 PM

How many CW do you use for CN212?

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Ryuno
sage


Reged: 05/09/13

Loc: Tokyo
Re: iOptron ZEQ25, initial impressions new [Re: Bluejay08]
      #6145422 - 10/18/13 06:59 PM Attachment (27 downloads)

Quote:

How many CW do you use for CN212?



I am using the included 5kg CW + PowerWeight (4.5kg) + extension shaft. See the image below (extension shaft is missing)

Heinz


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ramasule
member


Reged: 04/12/12

Re: iOptron ZEQ25, initial impressions new [Re: Ryuno]
      #6145995 - 10/19/13 02:08 AM

Try some vibration pads. Also as mentioned you can try adding weight to your eye piece holder. I know your hauling everything around so that may not be an option. If you want to get real fancy you can get a tension spring and attach the weight to the tension spring and the tension spring to your eye piece holder.

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DesertCrawler
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions new [Re: pippo]
      #6146768 - 10/19/13 02:08 PM

Quote:

Dear DesertCrawler,
could you tell us the specifications (length at rest, length at maximum compression, diameter of the wires,...) of the new spring sent to you by iOptron.

Thanks


Francesco

Francesco





I believe I posted the free length earlier in this thread but I did not specify the wire diameter or compressed length. The new spring from iOptron appears to be the same spring as what came stock but with a few extra turns.

It loos like free length is ~14mm; compressed ~6.5mm; wire diameter ~0.5mm.

In addition, I use two 0.25" diameter washers (~6mm) that are ~0.5mm thick.

The stock spring was ~12mm free length. I turn is ~2mm.

I intend to replace the washers with an additional spring as Astronewb has done. I believe his approach to be superior to the shims, although performance appears to be similar.


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Bill McNeal
sage


Reged: 10/07/07

Re: iOptron ZEQ25, initial impressions new [Re: DesertCrawler]
      #6146802 - 10/19/13 02:31 PM

Desertcrawler, who at iOptron sent you the springs? I took your advice and asked them for springs, but John provided the same response as Ryuno posted in the other thread discouraging replacement.

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pippo
member


Reged: 01/12/13

Loc: Paris (FR), Pantelleria (IT)
Re: iOptron ZEQ25, initial impressions new [Re: Bill McNeal]
      #6148106 - 10/20/13 09:54 AM

>asked them for springs, but John provided the same >response as Ryuno posted in the other thread discouraging >replacement.
I did as well and I got the same answer from John


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DesertCrawler
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions new [Re: pippo]
      #6148279 - 10/20/13 11:49 AM

If the spring is not at issue, what does iOptron suggest to resolve the problem? I would very much like to see an official explanation from iOptron for these issues many of us have experienced.

Kevin took care of it in my case. Kevin's knowledge and analysis skills were very good while we were resolving my problem. His suspicions matched mine -- insufficient tension on the worm gear to worm screw drive interface.

I find the response that the spring should not be replaced very strange in light of empirical evidence to the contrary. It is very clear the spring, or some aspect of the design or implementation, is insufficient. My mount was no better than a CG-1 out of the box even with only a f/6 2.5" refractor and DSLR mounted to it. That's under 4 lbs of equipment and less than 15% of the rated capacity.

Even after repairing it myself by assembling it the way to should have been from the factory, it was improved but still behaved poorly. It was not until replacing the spring that it came close to being something one might actually want to spend money on.

Had I not resolved this serious flaw I would have returned the mount for refund and purchased some other brand.

I want to like and recommend this mount without reservation. However, most people are probably not prepared to treat it like a kit, nor should they be expected to do so. For those willing and able to spend the time to get it working correctly, it can be a great instrument. It would appear that some combination of design and manufacturing process needs to be adjusted. Either way, iOptron need s to take care of those that shelled out nearly $1,000 for the mount yet remain unable to use it the way it was intended.

Long post, I know, but this topic gets me going a little bit. I remained silent about it for a number of months while the issues were being sorted out, even while the mount's praises were being espoused. Kevin was very committed to getting it working and maintained his patience even while mine wore very thin. Kevin is a credit to his position at iOptron and they as a company should be acknowledging him for his efforts. Had it not been for Kevin, I would have given up on this device.


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DesertCrawler
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions new [Re: DesertCrawler]
      #6148368 - 10/20/13 12:48 PM

As an update, I removed the washers previously used to shim the RA tensioner spring, and instead installed a spring to augment the iOptron spring.

The spring I used is Serva Lite #71XAU. I purchased it from a local Ace Hardware. Here it is just for reference albeit incorrectly listed as an extension spring: http://www.amazon.com/Extension-Spring-Length-Outside-Diameter/dp/B000VYFKMI

I snipped a 13-14mm length off each end of the spring and placed one inside each of the RA and DEC axis tension springs. This seems to work well but have not star tested it.


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Bluejay08
member


Reged: 09/29/09

Re: iOptron ZEQ25, initial impressions new [Re: DesertCrawler]
      #6148439 - 10/20/13 01:26 PM

If the payload is well balanced, shouldn't the spring have minimum effect?

Jay


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tango13
member


Reged: 03/16/11

Loc: Rome, Italy
Re: iOptron ZEQ25, initial impressions new [Re: Bluejay08]
      #6148531 - 10/20/13 02:45 PM

Quote:

I want to like and recommend this mount without reservation. However, most people are probably not prepared to treat it like a kit, nor should they be expected to do so. For those willing and able to spend the time to get it working correctly, it can be a great instrument. It would appear that some combination of design and manufacturing process needs to be adjusted. Either way, iOptron need s to take care of those that shelled out nearly $1,000 for the mount yet remain unable to use it the way it was intended.



I most definitely second this.


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Hunlon
member


Reged: 09/19/13

Re: iOptron ZEQ25, initial impressions new [Re: Bluejay08]
      #6148653 - 10/20/13 04:14 PM

Quote:

If the payload is well balanced, shouldn't the spring have minimum effect?

Jay




The spring actually is quite critical. It is there to apply a force on the worm drive screw against the worm gear - too little force and the engagement is not complete, too much force and you risk RA over-current due to motor overload. The evidence points to iOptron supplying springs that are too weak. In my case I couldn't get the "play" out of the RA even when it was screwed right down. I measured the PE at 65 arc seconds P-P which really is quite poor. As an aside when I reported the figures to iOptron they replied that I should not fully screw down the tension, it may be just that they are working from a script having been burnt from their first batch.

I too have gone down the replacement spring route. The springs I have sourced are the Century C500 and C510. I have been able to do the static tests that Paul has described and get a trip point of 3 1/2 turns with both springs and about 2 turns with just the C510. The mount appears to be much tighter now but I have not been able to perform any empirical tests yet due to lack of stars. Due to the fact that I would have to screw out the tensioner further with both springs than with a single spring, I think I may just go with one C510 spring as it should provide the same results.

I agree with the sentiments voiced in this thread regarding the design of the mount - sadly I have to concur as well regarding the quality control.

Good luck to all and clear skies,
Hunlon.


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RandyC
super member
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Reged: 04/01/13

Re: iOptron ZEQ25, initial impressions [Re: tango13]
      #6149513 - 10/21/13 09:40 AM

Mine worked out of the box. Yes, there was play in the RA axis and I was skeptical too. But when the motor boards started working, the play disappeared. Sometimes it takes a little time before it is totally gone and I am not sure what the firmware algorithm is. They have designed the system so there is protection of the motors. It doesn't necessarily disappear right away, only after some running or maybe after alignment. I have never found the play to interfere with goto accuracy or tracking. I am not sure what the exact algorithm is and maybe Ioptron would share. The only inaccuracy is after a meridian flip or spring slippage.

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DesertCrawler
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions [Re: RandyC]
      #6150554 - 10/21/13 08:38 PM

Quote:

Mine worked out of the box. Yes, there was play in the RA axis and I was skeptical too. But when the motor boards started working, the play disappeared. Sometimes it takes a little time before it is totally gone and I am not sure what the firmware algorithm is. They have designed the system so there is protection of the motors. It doesn't necessarily disappear right away, only after some running or maybe after alignment. I have never found the play to interfere with goto accuracy or tracking. I am not sure what the exact algorithm is and maybe Ioptron would share. The only inaccuracy is after a meridian flip or spring slippage.




It sounds as though we are observing different symptoms. The issue that I and some others have or had experienced is quite clearly mechanical and not something firmware would impact one way or the other. It is good to hear yours is doing what it is supposed to do. After some tuning thankfully mine does as well.

A properly balanced payload on this mount should not induce any slippage of the gears. Excess force applied to a well balanced axis would be expected to induce slippage. That's where the tensioner comes in.

When my mount arrived, the slippage could be induced with very small amount of force. The tensioner had almost no effect on limiting the tolerance to imbalance. Play was severe with small or modest well balanced payload. The RA axis had so much slop that when disassembled, the motor assembly could be wiggled on its hinge easily over 1/8 of an inch with two fingers. The motor should not move at all in relation to the hinge, but rather should pivot on the hinge as limited by spring tension.


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Seanem44
scholastic sledgehammer
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Reged: 09/22/11

Loc: Woodbridge, VA
Re: iOptron ZEQ25, initial impressions [Re: DesertCrawler]
      #6151180 - 10/22/13 07:34 AM

I just took mine out for a longer AP session two nights ago.

The only alteration to mine was adding electrical tape on the encoder caps.

I set it up, polar aligned, and aimed at M31. I set my D800's intervalometer for 30 2minute exposures, left it and went to watch TV. When I got back, I had 30 perfectly tracked exposures. No signs of trailing and M31 stayed in the exact place throughout all exposures.

I will caveat and say I believe mine is a more recent build, as I had purchased it in September and had a little wait time for it to come in.

No problems with my tension knobs. No slippage. Still have cross-talk every now and then, but while outside I can barely hear it.

I am happy with my choice of this instead of the AVX, which seems to have just as many issues. For me, the selling point is the polar alignment, which is by far the easiest I have ever seen.


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DesertCrawler
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Reged: 05/30/13

Re: iOptron ZEQ25, initial impressions [Re: Seanem44]
      #6151338 - 10/22/13 09:53 AM

Quote:

I just took mine out for a longer AP session two nights ago.

The only alteration to mine was adding electrical tape on the encoder caps.

I set it up, polar aligned, and aimed at M31. I set my D800's intervalometer for 30 2minute exposures, left it and went to watch TV. When I got back, I had 30 perfectly tracked exposures. No signs of trailing and M31 stayed in the exact place throughout all exposures.

I will caveat and say I believe mine is a more recent build, as I had purchased it in September and had a little wait time for it to come in.

No problems with my tension knobs. No slippage. Still have cross-talk every now and then, but while outside I can barely hear it.

I am happy with my choice of this instead of the AVX, which seems to have just as many issues. For me, the selling point is the polar alignment, which is by far the easiest I have ever seen.




Had mine worked out of the box I would be saying the same thing. I am still happy with the mount, but there's a bit of an after taste, unfortunately.

I have wondered if there was a bad run, or if it took a few runs to sort out the issues. Mine was purchased at the end of May 2013 and was either the last of the previous shipment, or the first of a new shipment, it is not clear. I had presumed it was a newer one due to the shorter springs since earlier ones had a longer spring.

Either way, it should be good news to prospective buyers if recent versions are working without modification.

While I have not yet enjoyed your level of performance, I am satisfied with what I am getting and am now confident that it will improve. Part of my issue has been environment. Vehicles driving down the street cause movements the camera can see but the eye cannot.

So, the whole cross talk issue is interesting and perhaps another thread. Cross talk is when the electrical activity of one circuit has an unintended effect on another electrical circuit. My mount does not exhibit that behavior as far as I have seen so far. I do observe the mount dithering fairly frequently. When this happens there is a singing sound from the motors which can vary in intensity even if the mount is at rest. I wonder if this is what people have referred to as cross talk. I would expect true cross talk to manifest itself in erratic and unpredictable movement in one or more axis. Dithering may cause minute changes in position but only on those axis affected, which could be both concurrently. Bumping the position with the hand controller could make the dithering stop.

Closed loop servo systems can exhibit this issue. The iOptron support party line seems to be that all closed loop systems dither. This is not true. There are ways to eliminate dithering but that would require appropriate decisions to be made early in the design process, decisions that no doubt would increase the price of the mount.

I am used to the dithering noise and, since it does not impact tracking or slewing accuracy, I have decided not to worry about it. I would prefer the mount to be quiet, however.

Anyway, I am glad yours works for you. Hopefully this is a trend for what appears to be an otherwise solid design.


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Seanem44
scholastic sledgehammer
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Reged: 09/22/11

Loc: Woodbridge, VA
Re: iOptron ZEQ25, initial impressions [Re: DesertCrawler]
      #6151384 - 10/22/13 10:12 AM

I guess it is what you refer to as dithering then. Sounds like electronic beeps, kind of like a dial up connection or something.

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ramasule
member


Reged: 04/12/12

Re: iOptron ZEQ25, initial impressions [Re: Seanem44]
      #6152335 - 10/22/13 07:42 PM

I believe its from the loose caps on the encoder bouncing on the encoder shaft causing it to flutter.

Load the encoder.shaft with a spring, fill in some of the encoder cap with epoxy, shave some of the edges of the encoder cap for tighter fit, tape the encoder cap down hard.

All those options work if, pick your poison, I taped mine.

If street traffic vibrates your mount this is likely your problem, true crosstalk as you stated is due to induced emf on cables via pulsing of stepper motors. However he encoder bouncing simulates he same thing... almost.


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