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AZ3 mount unsteady


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Hello, I have an AZ3 mount supporting a Skywatcher 120mm. My complaint is when I aim the telescope up by hand (not using the fine controls)  at an object, the telescope dips about half an inch so I end up trying to point the telescope half an inch higher, which is not always easy to get exactly right. In other words there seems to be too much play in the mount. Does anyone know whether this is normal or is there a solution, as it sometimes gets very annoying? Thanks anyone.

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I wish some enterprising company would offer a similar ready made solution for those of us who aren't so handy.

There are a lot of AZ3s out there which would benefit. I wouldn't have ditched mine if there was something.

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Mine is a M10 threaded bar bought on Ebay.

I then bough a set of three counter weights from Astroboot.

I used two wing nuts also bought on Ebay.

There is a m10 nylock on the very end of the bar to stop me over spinning the wing nut and it dropping off.

There are two m10 nuts and a washer each to secure the threaded bar to the bent peice of metal used to fix it to the mount.

It is quite crude and I expect there are better DIY ones out there but it was easy to get bits for.

I have to wait a moment for vibration to die down and I expect if I was clever with a bit of wood on the mount plate and perhaps some felt rings added to where the washers are that would help.

Only has one of the weights on it here. I might need two with the camera attached to the end of the ST80.

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There is a thought I had that maybe the Skywatcher Staradventurer counter weight bar might be useable with a bit of mount fashioning to add it to the AZ3. They were not in stock when I wanted to make this so I went DIY but I did wonder if I could have risked buying the Staradventurer one. here.

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RichieP, I think whoever makes the AZ3 should have fixed the problem.

Synta (who own the Skywatcher and Celestron brands) make the AZ-3 but it's a pretty straight copy of the Japanese made Vixen Custom-D mount which was, frankly, better engineered. The Vixen had a counterbalance as a manufacturers option whereas with the AZ-3 it needs to be a DiY effort.

The issue with the design is that the centre of gravity of the scope tube is held above the altitude axis which causes the tendancy for heavier and longer tubed scopes to become unbalanced when pointed above a certain altitude. This puts a lot of strain on the altitude bolt. The mount works better with lighter, shorter tubed scopes.

I used an AZ-3 with my 4" refractors for quite a while before deciding to move to mounts where the CoG of the scope tube and the altitude axis of the mount are at the same level, ie: the Vixen Porta Mount and Skywatcher's AZ-4. These, in my opinion, are better mounting solutions for all but the shortest and lightest scopes.

The AZ-3 is a low cost option though and very portable so perhaps a bit of DiY to get it to work with some scopes is worthwhile ?

Here is a report from someone who is putting the AZ-3 under even more strain than your scope does:

http://www.cloudynights.com/page/articles/cat/user-reviews/telescopes/120mm-130mm-refractors/orion%E2%80%99s-120mm-f8-on-an-az-3-alta-azimuth-mount-r897

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I think much better to make a counter weight then keep a wrench handy to tighten the bolt all the time. A mount in balance is surely freer to use the slow motion controls with as well.

Yes, I tend to agree.

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 I've experimented but I don't seem to have solved the problem with the 'play' in the mount whether with weights or wrenches, I think I need a new mount but will have to put up with my present one for now and continuing aiming an inch or so under the object  to reach it. Thanks everyone for your detailed suggestions.

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Well since I wanted a result as soon as possible I used my hand over the end of the telescope, after all it is still a weight! I've moved the telescope up and down the holding brackets but there is always that annoying upward flip when I lower the red dot finder sights, which by the way add to the annoyance by suddenly going out until I hit them. I've now bought a Skywatcher finder without illumination at least I know where I stand there.

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I have replaced the self-locking nut on the main pivot bolt with two thinner locknuts. Accurate adjustment is tricky, and required several attempts, but the end result allows me to use a 150mm SW F5 refractor succcessfully on my AZ3. I have, needless to say, spent time on carefully tightening all the screws and bolts in the mount and tripod, and I have also fitted dovetail clamps. If winds are high I place a spare counterweight in the spreader tray to achieve reasonable vibration damping,

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Thanks for that, but did you have this annoying flip up when you'd homed in on something and did your alterations solve it.? I'm not worried about the vibration I understand that.

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Well since I wanted a result as soon as possible I used my hand over the end of the telescope, after all it is still a weight

It is a weight but I don't think it is in the right place to create the counter weight affect which is needed to balance the telescope. The weight bar needs to stick out the front and balance across the cog.
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The basic problem with the AZ3 is that the Nylock self locking nut fails to self lock in this application. The repeated manual forward and backward manipulatio of the telescope on the altitude pivot required to access more than C15 degrees of altitude mitigates aginst it. The solution of this problem can be found in my post from 08.37 pm on the 30th March,

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I fitted another similar size nut by taking off the spring washer to make a little room,  I will have to wait until I go to B & Q as the local ironmongers don't have a smaller width nut. My experiment made no difference. Where did you fit the dove tail clamps?

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Thin locknuts in both steel and brass are available from Amazon. I sawed down a spare nut myself, as I had one to hand. The ADM Vixen style dovetail plate adapters (2) I bought from (I think) Rother Valley Optics. They currently cost £25 each from RVO, and I drilled holes in the AZ3 mount between the channel section and made suitable packing plates to suit. Although this would seem a relatively costly mod, I find it worthwhile for ease of use and to have a relatively lightweight grab and go set-up.

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I think I've decided on replacing the AZ3 with an AZ4-1. The telescope is now veering sideways and to stop this I've had to wind fishing line extremely tightly beyond the nut/washers to fill the gap I can see. The telescope continues  its 1" to 2" forward and backward rocking movement at any angle to 90 degrees. Weights may help but I would find them inconvenient, as I have to travel to use the telescope and the less I have to carry the better.

One thing though Coulthamst if you read this, can you describe what part  you call the 'Channel Section'? Thanks.

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