AZ3 Not Up to it ???

[Paul73]

Hi Guys

I've just aquired a nice ED80 from a fellow SGL'er. As far as I can see from a brief outing last night, it is a cracking little scope.

I also aquired a SW AZ3 mount from an online auction site. It seems newish and well looked after but the seller said that he was selling due to it not being up to handling his ST120. I took the view that as reputable dealers sell the ST120 with the AZ3, the problem would be boarder line. The ST150 is 50% heavier than the ED80. So I thought that I would give it a go.....

However, for targets over 25° the scope heads for the sky under its own gravity. I've tightened the big bolt on the alt baring. I've moved the scope as far forward as possible in its rings.

What should I try next?

Please note. I have been Dobs all the way until now. So it is entirely possible that I am making a really stupid mistake...

Any ideas?

Paul

PS. I am visual only at the moment.

[John]

I've been down a similar path with the AZ-3 Paul

I was quite stubborn for a while and used the mount with an ED100 and my Vixen ED102. You can counterweight the mount to stop that tipping back issue but I decided to move the an az-mount where the centre of gravity of the tube is at the same place as the altitude axis. My first step was to a Vixen Porta Mount which worked very well and was light weight with slow motion controls too. It's quite a bit more expensive than the AZ-3 though. I then moved to an AZ-4 on a steel tubed tripod which had a bit more capacity than the Porta Mount but has no slow motions and is quite a bit heavier.

On balance I'd say the Porta Mount would be very, very nice for your ED80 if you can get one

[Thalestris24]

Hi

You could try balancing the scope. Some sort of counterweight attached to the ota would probably help.

Louise

[spaceboy]

Might help  http://stargazerslounge.com/topic/187619-visual-mount-for-ed80/?p=1954725

[Macavity]

If your feeling more adventurous, you could try adding springs!

I found it was still difficult to get good balance with weights. With a 

spring system, the return force increases as the scope is moved 

towards the zenith. Which is sort of what (I suspect) you need. 

[John]

That looks like some type of robot Chris ! - great idea though

[Macavity]

Heheh, Thanks, John. There isn't much metal to play with, but there

is room to drill an M6 hole in the mount body. Of course, you have

to use quite strong materials or you'll "have someones eye out".

[happy-kat]

I have added a counter weight bar to my az3, very easy to do, I had no weights already so got some from astroboot.

I have my altitude bold not tight so that the slo mo control works easy.

[andrew63]

I would keep a look out for a used porta or az4 - then you will really enjoy the telescope. andrew

[damnut]

Now Then you mention the ST120, then the ST150..... I have an AZ3 and an St120, never the twain shall mix, as for a ST150, well beyond the mounts capacity. I used to have a pair of mole grips on the main nut, even with a counter weight it is just on the limit of the mount wit the ST120. If you can try an az4,  it is a revelation ...

[Paul73]

Thanks guys.

Chris - Your spring solution looks great with the increasing pressure just when you need it. And you haven't added to the amount of kit that you need to cart around!

Damien - ST120 not ST150. As you say if the 120 is on the edge!!

Does anyone have any photos of succesful counterweight arrangements?

Lastly, could I fit a AZ4 head on my current tripod?

Paul

[happy-kat]

http://stargazerslounge.com/topic/222894-az3-saddle-and-counterweight-mod/?fromsearch=1

http://www.spacegazer.com/index.asp?pageid=97490

[Paul73]

Thanks Happy-Kat

That is exactly what I am looking for. Cheap and requiring minimal metal working skills.

I'll try this first. Chris' "take someone's eye out" option, although very neat, may be a bit beyond my minimal skills.

Paul

[happy-kat]

I thought the triplet can't weigh a lot different to your st120 in the second link and that is the way I have done mine.

I have the camera mount plate on my az3 as my telescope uses that sort of fitting as no tube rings.

Picture of weight with a camera mount bottom of link

http://stargazerslounge.com/topic/208717-new-arrival/?fromsearch=1

[Paul73]

Cool.

I've ordered the parts from Astro Boot and Ebay. So just got to wait, get drilling and bending!

I'll post some pictures when done.

Thanks for everyone's input.

Paul

[JamesF]

I've not tried the ED80 on the AZ3, but given that the only problems I had with the ST120 were near the zenith I'm surprised that it's so awkward.  Hopefully the counterweight should sort it for you.

James

[Paz]

I've just got an AZ3 that came with an ST120 for not much more than the cost of just buying an OTA on its own - it is fine without modifications for terrestrial and low altitude viewing where you are not varying the altitude much but the friction bolt for locking the altitude is not a user friendly piece of design - you have to have a 19mm spanner with you all the time to unlock/lock it!

[happy-kat]

Have a read of the links above about how to fine tune the mount.

[Dave In Vermont]

I had a similar problem with an Orion AZ-4 Alt.Az. mount I picked up at 1/3rd the original price from Orion-USA. It would let go and drop it's load - my ST80 - if you so much as breathed on it! So I took it apart.....

Using 2 4mm allen-wrenches to disassemble the altitude-clutch in the upper-middle of the photo, and took out a shiny stainless-steel drum. The mount was supposed to hold 10-pounds by means of tightening a simple alloy-bolt - sticking out of the rounded casing to the left and bottom of the first photo. So here's the problem: An alloy-bolt was supposed to handle 10-pounds by being tightened down onto the shiny, smooth stainless-steel drum. And that certainly wasn't going to work. There was nothing for this bolt to engage - the drum is as smooth as can be! So it needed something it could grasp. So.....

I cut a strip of 80-grit sandpaper long enough to wrap around the steel drum. And using my Gorilla-Glue - which is like super-glue on steroids - I glued it in place. Now the bolt had the coarse grit of the sandpaper to hold onto. I re-assembled the mount and tested it. It worked perfectly. And it could hold more than 10-pounds. If and when the sandpaper finally loses it's grit, I'll buy a god and sharp metal-file and go to town on the steel-drum. I would have done this in the first place, but don't have a proper file. Yet.

I Hope someone can benefit from this tale of engineering retro-fit.

Dave