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Tuning the ZEQ25, YouTube link

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#26 Astronewb

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Posted 14 October 2013 - 08:44 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.


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

#27 Astronewb

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Posted 14 October 2013 - 08:48 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

#28 ramasule

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Posted 14 October 2013 - 10:18 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

#29 Bill McNeal

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Posted 15 October 2013 - 06:05 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?

#30 ramasule

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Posted 15 October 2013 - 08:56 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.

#31 Astronewb

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Posted 15 October 2013 - 09:53 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?


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

#32 cuivienor

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Posted 15 October 2013 - 10:22 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

#33 Bill McNeal

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Posted 15 October 2013 - 10:53 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?

#34 ramasule

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Posted 15 October 2013 - 11:32 PM

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

#35 Bill McNeal

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Posted 16 October 2013 - 06:37 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?

#36 mikeboni

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Posted 16 October 2013 - 09:05 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?

#37 Astronewb

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Posted 16 October 2013 - 09:34 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?


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

#38 Astronewb

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Posted 16 October 2013 - 09:36 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?


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

#39 Bill McNeal

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Posted 16 October 2013 - 10:45 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.


#40 ramasule

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Posted 17 October 2013 - 12:02 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.

#41 Astronewb

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Posted 17 October 2013 - 06:27 AM

also if you add to much and you wreck your motor when you hit something, paper weight.


Ramasule is right about the spring length. But not so right about wrecking your mount if you hit something (tripod).

Because some AP'ers will at one time or another run their cameral into a tripod leg, this is what will happen:

Tracking speed is extremely slow, and the encoder motor has a ton of torque because of the planetary gear reduction.

So, when the mount meets an immovable object (tripod) the motor will force the hinge base loose from under the locking screws and move it until all the free space in the hinge holes is taken up, then the current load will trip a Overcurrent message and the mount will stop tracking.

At that point, you will need to disassemble the mount and reseat the worm mesh (the worm housing will be canted).

Been there, done that, with no detrimental results...:)

Cheers...Paul

#42 ramasule

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Posted 17 October 2013 - 10:16 AM

Well john paul :p this is something I don't want to try, ill take your word for it.

Regardless, it seems a couple of you are running out to "fix" a good mount. I encourage mount disassembly if you like that sort of thing and arent rushed. However as stated if your mount holds well, and your not mechanically inclined, you probably should not take it appart. Myers mount was fine from factory, however I enoy taking things apart. So I grabbed a bunch of springs and tried them all out. There is no set spring tension, just have fun.

Clear skies

#43 Ryuno

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Posted 18 October 2013 - 04:44 AM

Just for you information. Yesterday, iOptron Support sent me the following mail:

"I would like to share some info with you. A customer sent his ZEQ25 mount in for adjustment after he watched Paul’s video at CN and he determined he had a lot play on his mount and the RA slipped with 20 lbs payload. We received his mount and checked by our technician, both RA and DEC had almost zero play and the RA did not slip when 20 lbs payload was applied. However, if the DEC was not balanced, the RA would slip.

We would not recommend putting the CW at the end of the shaft and then test the RA slippage by loosening the tension adjuster by 1, 2, … turns. Z balanced mount is designed to work ideally when both DEC and RA are well balanced. We would strongly recommend balance the DEC first and then RA. We would suggest customers never shack/wiggle the CW shaft to test any play, such action could create play."


#44 Ryuno

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Posted 18 October 2013 - 05:05 AM

...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...

Paul

I just would like to stress that this step is crucial. The first time I did not do this, with the following result, when trying to slew in RA at speed 8. Listen to the sound. At 2 turns out, it stopped with RA overcurrent. (1 turn = 360 degrees)

Tension screw 4 turns out
3.5 turns out
3 turns out
2.5 turns out
2 turns out (motor-stop with RA overcurrent)

All the best for your tuning.
Heinz






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