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Equipment Discussions >> Mounts

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pippo
member


Reged: 01/12/13

Loc: Paris (FR), Pantelleria (IT)
Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6135356 - 10/13/13 04:30 PM

Indeed you are correct. It is too dangerous to add material especially with my 14mm length spring. The remaining space is just 2mm and it is possible to reach the situation you are describing. So I agree with you that is safer to find a stronger spring....

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Hunlon
member


Reged: 09/19/13

Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6137628 - 10/14/13 06:30 PM

Hi Paul,

It seems to me that if the spacer brings the total length to 1/2" you would have the same spring tension as the original spring. This is because F=kx, where k is the stiffness and x is the compression and it doesn't matter if the spring is 1/4" long or 1/2" long, compressing it by 1/8" will generate the same force. I agree that making the total length longer than 1/2" will risk 'coil bind' so would not be a good idea.

The fact that you get better performance by adding an inner spring indicates that the original spring stiffness is too low and should be increased. The ball is now in iOptron's court. I just hope they've made the appropriate adjustments to their production line.


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ramasule
member


Reged: 04/12/12

Re: Tuning the ZEQ25, YouTube link new [Re: Hunlon]
      #6137728 - 10/14/13 07:50 PM

Yes if you compress 1/8" on both springs same force, however a 18mm spring will compress further then a 15mm spring with 3mm spacers.

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Hunlon
member


Reged: 09/19/13

Re: Tuning the ZEQ25, YouTube link new [Re: ramasule]
      #6137817 - 10/14/13 08:40 PM

Quote:

Yes if you compress 1/8" on both springs same force, however a 18mm spring will compress further then a 15mm spring with 3mm spacers.




Point taken. But the amount of force applied to the worm is proportional to the compression of the spring. This compression is achieved by screwing in the tension knob. The maximum force available is the amount of compression - it doesn't matter how long the spring is. Having a longer spring means that your range of compression is longer and therefore the maximum force is higher but if your screw only compresses the spring by, say, 6mm you will only get 6mm worth.


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Tony Finnerty
member


Reged: 03/06/13

Loc: Nevada City, California
Re: Tuning the ZEQ25, YouTube link new [Re: Hunlon]
      #6137897 - 10/14/13 09:31 PM

Thank you, Paul, for the tuning videos. I replaced each tensioning spring with two 0.5 inch springs as suggested, then did the whole tuning thing for both axes. Last night it just worked. PHD gave Osc-index values of 0.16 to 0.27 and RMS 0.10 to 0.15 through approx. 400 subs totalling 5 hours exposure time, with round stars.

Contrast was less in the moon-bright sky, but autoguiding worked well, even though missed guiding steps due to star mass variations (twinkling) were frequent. With short (1 minute using my 100mm, f/2.0 lens) exposures due to sky brightness, I didn't need autoguiding at all. The tuned ZEQ25 is a keeper.


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: Tuning the ZEQ25, YouTube link new [Re: Tony Finnerty]
      #6137919 - 10/14/13 09:44 PM

Quote:

Thank you, Paul, for the tuning videos. I replaced each tensioning spring with two 0.5 inch springs as suggested, then did the whole tuning thing for both axes. Last night it just worked. PHD gave Osc-index values of 0.16 to 0.27 and RMS 0.10 to 0.15 through approx. 400 subs totalling 5 hours exposure time, with round stars.

Contrast was less in the moon-bright sky, but autoguiding worked well, even though missed guiding steps due to star mass variations (twinkling) were frequent. With short (1 minute using my 100mm, f/2.0 lens) exposures due to sky brightness, I didn't need autoguiding at all. The tuned ZEQ25 is a keeper.




Thanks for the update. That sounds like what the mount is capable of producing, given that all the 'variables' are removed.

I have a collection of PHD graph screenshots from the past several months, that most people would frame. The smoothness of the mount when tracking is an indication of how little periodic error the mount really has.

It's all due to the Z Balanced design, which just puts the offset weight where the mount can easily deal with it.

I don't see any need for a mount other than the Z for AP, especially in this payload and price range.

Cheers,

Paul


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6137925 - 10/14/13 09:48 PM

Hunlon and Ramasule. You are neglecting one important piece of data when it comes to compression springs. The wire diameter of the spring. Two springs, of identical length, but one has .012" spring wire, the other has .010".

The spring with the larger diameter wire will coil bind first, every time, at maximum compression.

The only springs that are not plagued with coil bind, are conical springs, which, if designed correctly will collapse into a space equal to the diameter of the wire.

Let's move on...

Paul


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ramasule
member


Reged: 04/12/12

Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6138074 - 10/14/13 11:18 PM

I don't even know what I'm moving on from.

What I do know is that I was supposed to get clear nights 4 nights in a row now and I didnt even get 1

DRATS


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Bill McNeal
sage


Reged: 10/07/07

Re: Tuning the ZEQ25, YouTube link new [Re: ramasule]
      #6139635 - 10/15/13 07:05 PM

Paul, in Part 2 at around 2-5 minutes for worm mesh adjustment, it appears you loosen the 3 allen bolts, tighten the tension screw with a spacer, then tighten the allen bolts.

Which part actually adjusts the worm mesh and how can you tell what the right amount is?


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ramasule
member


Reged: 04/12/12

Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6139886 - 10/15/13 09:56 PM

The metal part that you loosened the 3 bolts on is the tensioner. What sets the mesh is,

You tighten down hard on a 1-2 mm spacer, this will slide the metal tensioner around to give you a near bind mesh with the screw that spacer amount. This is what is setting the proper mesh in regards to jsing the 1/2 springs and ball bearing.


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6139977 - 10/15/13 10:53 PM

Quote:

Paul, in Part 2 at around 2-5 minutes for worm mesh adjustment, it appears you loosen the 3 allen bolts, tighten the tension screw with a spacer, then tighten the allen bolts.

Which part actually adjusts the worm mesh and how can you tell what the right amount is?




Hi,

With the 3 hinge lock bolts loose, run the tension screw all the way down onto the spacer. That will force the worm into the concave area of the ring and center it. There is nothing else, the worm establishes a mesh because you have run it to the bottom of the ring, it can't go anywhere else, you just have to keep it centered over the ring when tightening the hinge bolts. The tension screw spring and ball determine how much force is applied to keep the worm in mesh with the ring gear when operating.

Before tightening the 3 lock screws, eyeball the hinge base to make sure it is aligned with the raised base on the mount, ie; not angled right or left.

Once you determine it all looks square, tighten the 3 cap screws locking the hinge base to the mount. Then back off the tension screw and remove the spacer.

You can now install the ball and spring, tighten it all the way down and back out 1 turn. Grab the cogged belt on the worm pulley and roll it back and forth to make sure the worm and ring gear turn easily with little force. (It's easier with the belt because the worm pulley is hard to access in the housing.

Now reinstall the encoder motor and remaining parts and go have a party....;)

Hope that helps?

Paul


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cuivienor
professor emeritus


Reged: 10/07/10

Loc: Tokyo, Japan
Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6140037 - 10/15/13 11:22 PM

Paul, thank you so much for the videos!

My SmartEq Pro recently broke (i.e. the RA axis would happily and smoothly turn when locked). I did manage to fix it (iOptron Support sent me a full diagram/blueprint of the axis components so I dissassembled and reassembled and now it works again), but decided it was time to go to the ZEQ25GT. I will report back once I have it!

Cheers,

Yannick


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Bill McNeal
sage


Reged: 10/07/07

Re: Tuning the ZEQ25, YouTube link new [Re: cuivienor]
      #6140084 - 10/15/13 11:53 PM

Thanks Paul!

My mount needs tuning based on your test, as the CW shaft gives when tension screw is turned out 720 degrees. Does this mean its tracking is affected or payload reduced?

Also your videos didn't go over spring replacement. It sounds like you tested after tuning by replacing the original springs and the big difference indicates the spring is the biggest factor in reducing RA play. Did you get them from iOptron or hardware store? If I have to ask the Home Depot guy for half inch springs, what else should I specify regarding the part?


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ramasule
member


Reged: 04/12/12

Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6140133 - 10/16/13 12:32 AM

Bill check the other zeq thread it has all the info you need. If you are in the states McMaster Carr probably has springs.

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Bill McNeal
sage


Reged: 10/07/07

Re: Tuning the ZEQ25, YouTube link new [Re: ramasule]
      #6141651 - 10/16/13 07:37 PM

OK thanks.

So replace the tension screw spring with two springs, outer and inner, half-inch.

Is everyone doing this for the RA tension screw, or also for DEC?


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mikeboni
newbie


Reged: 10/05/13

Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6141925 - 10/16/13 10:05 PM

Hiya folks,

I'm a new ZEQ25 owner, very grateful to Paul for making the tune up videos. I'd like to replace my springs, but HomeDepot had nothing, and the springs at the local Ace Hardware were close but not quite right. I just spent some time at McMaster Carr looking for springs with the right specs, but no luck there either, at least not with the specs Paul posted.

Paul, where'd you get yours? Or anyone else know of a good supplier?


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: Tuning the ZEQ25, YouTube link new [Re: mikeboni]
      #6141980 - 10/16/13 10:34 PM

Quote:

Hiya folks,

I'm a new ZEQ25 owner, very grateful to Paul for making the tune up videos. I'd like to replace my springs, but HomeDepot had nothing, and the springs at the local Ace Hardware were close but not quite right. I just spent some time at McMaster Carr looking for springs with the right specs, but no luck there either, at least not with the specs Paul posted.

Paul, where'd you get yours? Or anyone else know of a good supplier?




I buy all my supplies from Reid Supply, the springs are number S-780 and S-555, but the shipping will kill you unless you're buying in quantity.

Best...Paul


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Astronewb
scholastic sledgehammer
*****

Reged: 09/19/11

Loc: Connecticut
Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6141987 - 10/16/13 10:36 PM

Quote:

OK thanks.

So replace the tension screw spring with two springs, outer and inner, half-inch.

Is everyone doing this for the RA tension screw, or also for DEC?




Hi Bill, I use them on both RA and DEC. Replacing the stock spring with these will give you some extra worm tension and is probably all your particular mount needs?

Cheers,

Paul


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Bill McNeal
sage


Reged: 10/07/07

Re: Tuning the ZEQ25, YouTube link new [Re: Astronewb]
      #6142067 - 10/16/13 11:45 PM

Thanks Paul.

Anyone know if iOptron is using the new springs? If so, we can ask them to send the parts for user replacement.


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ramasule
member


Reged: 04/12/12

Re: Tuning the ZEQ25, YouTube link new [Re: Bill McNeal]
      #6142164 - 10/17/13 01:02 AM

You do not need new springs if they are 1/2 inch long and your mount holds your cw 2 turns out.

Also it does not need to be exact when adding springs, also if you add to much and you wreck your motor when you hit something, paper weight.

If you want stiffer and your main spring is 1/2 long then just find a spring that fits inside of it and go from there.


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