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Hi

I got my Skytee just over a month ago and have had a small problem with movement of its axes. Basically, there is about 1mm of play in both the main axes with everything clamped down as tight as can be. This shows up without a scope mounted: just gripping the "T" and twisting back and forth with my hands reveals a sudden movement.

I've sent videos to the supplier and obtained permission to attempt to tighten it up without risk to the warranty.

However, how to do it? 

I've seen talk of grub screws and lock nuts and the like but it would be handy if anyone has a step by step guide, particularly on how to adjust the up/down axis which is the one that is most annoying. Using the right tools is a concern as well, that warranty amnesty might go out the window if I'm belting it with a club hammer :-)

This link goes to a video showing the problem:  video

Any help would be appreciated.

Cheers

Dave

 

 

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Think this is standard on all Skytees. I certainly have play in mine and don't worry too much about it really. 

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Hmmm... the only reason I bought mine at all was because of the problems I had with previous mounts and the assurance that the skytee would fit the bill and would be "rock solid"....

 

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When tracking object at high magnifications there is no effect of this play at all. It only becomes an issue if you knock the scopes on the mount. All you then need to do is move the scope back in the opposite direction of this play and you will have the object in view again quite easly. In practice when observing I don't find this play a problem at all. I believe all mounts like this even other manufacturers will have a slight play in them still. 

Edited by Knighty2112

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That slack is due to altitude slow-motion assembly.  You might be able to reduce it some, but as long as you have a slow-motion control integrated, there's going to be some slack; same for a manual EQ-5 equatorial mount; same for my CG-4(EQ-3).  The SkyTee-2 and the EQ-5 actually have a few parts in common, from what I've read.

It's a sad state of affairs nowadays, as these mounts are all made in China, and not in Japan as they once were.  They're all made by Synta Optical, including my CG-4.  

That results in having to take the mounts apart, removing the factory glue-like grease and replacing it, and even making parts for it in some cases; for example...

https://www.eastmidlandsstargazers.org.uk/topic/4808-modding-the-skytee-2/

https://stargazerslounge.com/topic/199208-skytee-2-maintenance/

However, I would first check to see if you might adjust it to where it's a bit tighter.

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11 hours ago, Knighty2112 said:

When tracking object at high magnifications there is no effect of this play at all. It only becomes an issue if you knock the scopes on the mount. All you then need to do is move the scope back in the opposite direction of this play and you will have the object in view again quite easly. In practice when observing I don't find this play a problem at all. I believe all mounts like this even other manufacturers will have a slight play in them still. 

Hi Knighty

I wish I could be so sanguine as you, but my experience has been very disappointing.

Example:  observing Jupiter.  I line up the planet in my finderscope and lock down the mount. Jupiter in smack in the middle of the eyepiece view. I then adjust the focuser - the resulting movement is enough take the planet entirely out of the field of view of the eyepiece.

Or when "nudging" with the clamps unlocked I position the planet right in the centre of the view, then let go of the eyepiece and it jerks to some other position. It can end up anywhere in the field of view, usually right at the edge necessitating further adjustments.  Observing then can only get done in brief interludes between adjustments.

I do agree that the slack doesn't seem to affect use of the slow motion controls so much, once the scope has moved and settled at the lowest point of the slop.  However, the lack of tightness with the clamps unlocked makes it difficult to track by nudging. And when you clamp the locks tight, there really shouldn't be any movement at all from a 3Kg scope on a mount rated for 2x 13kg. My manfrotto camera tripod heads are perfectly rigid when clamped and they are one tenth the weight and dimensions.  It's just simple engineering.

I remember seeing posts on here that say the skytee can have the play adjusted out by tightening internal bolts and I have seen a step by step guide for the left-right axis but not the up down.

Can anyone help out with this?

 

 

 

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I had much the same problems as you when I first got my Skytee. I posted a question on here and followed the advice given and did manage to tighten things up so that there is now very little play when observing. Try searching for my post. I also found that using the side on mount and carefully balance my scope, a 120 ED, greatly helped. I have not had a chance to try mounting 2 scopes yet.

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On 05/04/2017 at 10:31, digital_davem said:

Hi Knighty

I wish I could be so sanguine as you, but my experience has been very disappointing.

Example:  observing Jupiter.  I line up the planet in my finderscope and lock down the mount. Jupiter in smack in the middle of the eyepiece view. I then adjust the focuser - the resulting movement is enough take the planet entirely out of the field of view of the eyepiece.

Or when "nudging" with the clamps unlocked I position the planet right in the centre of the view, then let go of the eyepiece and it jerks to some other position. It can end up anywhere in the field of view, usually right at the edge necessitating further adjustments.  Observing then can only get done in brief interludes between adjustments.

I do agree that the slack doesn't seem to affect use of the slow motion controls so much, once the scope has moved and settled at the lowest point of the slop.  However, the lack of tightness with the clamps unlocked makes it difficult to track by nudging. And when you clamp the locks tight, there really shouldn't be any movement at all from a 3Kg scope on a mount rated for 2x 13kg. My manfrotto camera tripod heads are perfectly rigid when clamped and they are one tenth the weight and dimensions.  It's just simple engineering.

I remember seeing posts on here that say the skytee can have the play adjusted out by tightening internal bolts and I have seen a step by step guide for the left-right axis but not the up down.

Can anyone help out with this?

 

 

 

Sorry it's as bad as that for you. Although there is some movement on my Skytee, setting the focus on the scope doesn't cause the object in the fov of the EP to move out of the fov at all, even with my f11 'frac. Granted on higher magnification there is some wobble when doing this, but still not enough to cause the Skytee to move out of position.  Maybe you need to add a couple of weights to the weight bar to give it a little more stability perhaps so it's not as light perhaps which might be what is causing the mount to move easier. I normally have two weights on mine, even when only using one scope on it, whitch is normally either my f11 or f8.3 'frac.

The amount of movement in your video is about the same as what I get, yet even without weights fitted  to my mount adjusting the focus on my scope doesn't move the image of Jupiter out of the EP. Is your focuser stiff that requires extra effort to focus the scope at all? Also, at what magnification are you trying to do this when you lose Jupiter or star or whatever in your EP?

Edited by Knighty2112

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Hi

I'm not sure what to do with the counterweight on an alt az (it's kind of obvious on an EQ) so I screwed the bar into the top mount and put the weight in the middle. It does help - now I can nudge with the clamps unlocked reasonable smoothly and it doesn't drift under the scope's weight. It's very usable like this.

I still don't really understand why such a huge mount isn't rock steady, though. There should be zero movement with the clamps locked. Given that a simple cheap camera ball head is completely steady within its weight limit it doesn't say a lot for SW's quality control. The clamps are effectively useless as they don't clamp!

 

 

 

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3 hours ago, digital_davem said:

Hi

I'm not sure what to do with the counterweight on an alt az (it's kind of obvious on an EQ) so I screwed the bar into the top mount and put the weight in the middle. It does help - now I can nudge with the clamps unlocked reasonable smoothly and it doesn't drift under the scope's weight. It's very usable like this.

I still don't really understand why such a huge mount isn't rock steady, though. There should be zero movement with the clamps locked. Given that a simple cheap camera ball head is completely steady within its weight limit it doesn't say a lot for SW's quality control. The clamps are effectively useless as they don't clamp!

 

 

 

Any system with gears in them will have play in them, this mount is no different as the gears that control the slow motion have this play also. A simple camera ball head has no gears, and clampling is done directly onto the ball head. With no gears in its system there is no play, so can be secured with no play. 

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1 hour ago, Knighty2112 said:

Any system with gears in them will have play in them, this mount is no different as the gears that control the slow motion have this play also. A simple camera ball head has no gears, and clampling is done directly onto the ball head. With no gears in its system there is no play, so can be secured with no play. 

Makes sense. So the movement is in worm drive rather than the main bearings?

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5 minutes ago, digital_davem said:

Makes sense. So the movement is in worm drive rather than the main bearings?

Yes, 99% of the movement is from the gears. There will also be a very slight play in the bearing too, but it is minute compared to the play in any gear chain. 

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22 hours ago, Knighty2112 said:

Yes, 99% of the movement is from the gears. There will also be a very slight play in the bearing too, but it is minute compared to the play in any gear chain. 

When the locking clamps are unlocked, is the worm drive doing anything - it feels like it is bypassed.

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When you unlock the clamps, the slow-motion assemblies are indeed bypassed, and for freedom of movement.

Incidentally, when tightening the clamps, don't overtighten them, if such as possible, as the mount is made of aluminum, and can result in stripping out the threads.

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14 hours ago, Alan64 said:

When you unlock the clamps, the slow-motion assemblies are indeed bypassed, and for freedom of movement.

Incidentally, when tightening the clamps, don't overtighten them, if such as possible, as the moun int is made of aluminum, and can result in stripping out the threads.

Given the amount of slop, i wont be locking them at all. Still don't understand why there so much movement. I don't think k the gears in this thing would be much use in a clock or watch....?

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See if you might exchange it for another.  Perhaps the next will be more satisfactory.  If not, then you can feel free to take it apart and see what makes it tick, and perhaps learn how to reduce the slop.  Make it your own, and in improving it despite the factory state in which it arrived.  Such will be your quiet victory as you observe with it under stars, refurbished.

We all have our little battles that we wage with this imported equipment; like the ubiquitous, wonky plastic focussers found among the entry-level Newtonians; and the useless setting-circles on the equatorial mounts.

A poster within another astronomy site suggested valve grinding compound impacted into the worms and gears, then to use a drill motor to spin the worms and gears at a fast clip in order to grind and polish the components to improve their mating; the meshing of the two.  That might reduce the slop as well.  

Here's what he said exactly...

https://www.cloudynights.com/topic/529736-the-celestron-cg-4-unveiled/?p=7091269

Then, there's always...the AZ8...

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p7966_Losmandy-AZ8-Alt-Az-Dual-Telescope-Mount-with-Tripod.html

...although it, too, has slow-motion controls.

Edited by Alan64

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When using my Skytee 2 l find the balance point of the scope then offset it by 15mm or so ( i.e. slightly out of balance), this ensures that one of the slo mo's is always in contact with one side of the worm gear. The movement you notice is because it flips from one side of the worm gear to the other due to manufacturing tolerances and a perfectly balanced scope.

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