What to do with an az3 mount and tripod

[LondonNeil]

Hopefully FLO will deliver me a new steel tripod and gtix this coming week,  yay.   I will then have an unloved and unnecessary lightweight alu tripod and az3 mount.   I need help deciding what to do with it.   Burn it with fire? Sacrifice to the god of clear skies? Repurpose (shudder!), bin,  or sell (is it even possible?)

This is the az3 and tripod that is packaged with a skywatcher st120.   In terms of costs the package is £379 but the ota is £299. However the ota still comes with rings and also a dovetail,  I'll be keeping the rings (and buying dovetail.... should arrive with the gtix) so just tripod and az3 is....£50 ish in 'cost'.  

In terms of function i actually thought the tripod ok, and belive the az3 is OK for smaller scopes like the st80, its just far from man enough with a 120 and 2" eps.   So maybe of use to someone for a small scope, or for binoculars maybe?  (A short person...or seated) I can't imagine selling it for more than a tenner plus postage though, and would I find a buyer quickly?  See my problem works be I'd see an st80 or skymax 90 or something before I sold the tripod and mount and somehow I'd end up with that..... which is daft...I do not want to go down that route.

Your advice please.  Stick it in the classifieds at a tenner plus postage,  or bin it in some amusing sacrificial manner that benefits the whole community by pleasingc the god known as 'Cloud'?

[happy-kat]

I's a tripod can be used for all sorts it's not end of life, it even has a use as a potential basic wedge.

[John]

I've found the AZ-3's useful for small, short scopes such as the ST80, 90mm mak-cass and a PST.

I even put a C5 SCT on one for a while and it worked OK - not with the Ethos eyepiece though !

 

[LondonNeil]

No it's not end of life,  it's fully functional,  just not for a scope I have. I'm most impressed John got that c5 sct on one though. 

Wedge would be a greatt idea except.... it won't with my scope.   The problem is with higher alt targets the c o g of the ota is well behind the alt pivot so with an ota other than a very small and light one it can't hold it .... it just sags away.   It would do the same being used as a wedge wouldn't it?

[windjammer]

Even with an ST80 it needs counterweight arms.

[John]

12 minutes ago, windjammer said:

Even with an ST80 it needs counterweight arms.

The AZ-3 is a chinese copy of the Vixen Custom Alt-Az mount. Vixen had a counterweight arm as an accessory for the mount. With the chinese version, you have to do a DIY job.

[LondonNeil]

I've seen threads for that 

[PeterStudz]

Do you ever go on holiday, or maybe thinking of going abroad, to have a family break to somewhere via aircraft that includes a truly dark sky? If so then the AZ-3 plus a small relatively cheap telescope would make an ideal travel package.

I’ve done similar and it was brilliant. Eg every single night cloud free and crystal clear. Warm/hot so observing in t-shirt & shorts. Milky Way so bright we could see the reflection on the water. I can remember being amazed that I could see the swan nebula naked eye. That’s before looking through telescope which, though small, gave then best views of DSO I’ve seen so far. 

 

[LondonNeil]

You're a wicked man,  you're speaking to my weak side!

[Peter Drew]

I like the AZ3, I have two.  I wouldn't buy an alt-az mount that didn't have manual slow motions and at their price the AZ3 is a bargain.  The out of balance issue is relatively easy to DIY address.  I use an AZ3 exclusively for solar observations with small Ha telescopes, an easy method I have found to cure the out of balance problem is to wrap one end of a bungee strap round the front of the OTA and the other end to somewhere on the tripod.  If you use enough tension on the strap to hold the telescope horizontal then as the telescope raises so does the tension on the bungee.  This leaves the system in equilibrium and nicely controlled by the slow motions.  🙂

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[Rusted]

At a glance the AZ3 has all the GEOMETRIC weaknesses of most altazimuth heads.
Including the expensive garbage sold for DSLRs with telephoto lenses.
The advertising crooks lie about fluid heads having enough friction to balance any load. Garbage!

The mass of the telescope and/or camera rides well above the load bearing pivots.
The slightest change away from horizontal will result in a greatly increased vertical moment.
[mass x distance around the pivot point] Maximum moment or imbalance is with the OTA vertical.
Which load is very poorly accepted by the weak, built-in design of most of these heads.
Including the crap "techno" friction designed into garbage camera heads like Manfrotto. 

How to overcome the problem?
Screw, fix or trap a piece of plywood or scrap aluminium/ CF across the OTA mounting plate or dovetail.
Then add weights on long stalks to the crosspiece, well below the instrument, until vertical balance is achieved.
Eventually you will find a neutral moment [mass x distance] below the mountings pivots.
For your chosen OTA or DSLR big lens setup. It should then swing effortlessly up and down in altitude.

The twin weights should not contact the tripod because the OTA isn't ever titled sideways. 
It remains upright. The longer your weight stalks the lighter the counterweights can be.
Use common sense here to avoid tripod leg contact or unwanted bulk. 12mm hardwood dowels would probably do.
Just avoid flexure causing vibration or catastrophic breakage. Or weight detachment! Eek! 😱
Aluminium tubing is widely available. 12mm or half inch Ø?

My childish drawing exaggerates the distance from the OTA to the heads vertical pivot.
The weight bearing cross plate is shown as a grey line just above the pivot.
You need twin counterweights, one on each side, to clear the tripod.
I missed the Thursday class in sophisticated 3d animation.

Edited February 11 by Rusted
Added image

[LondonNeil]

10 hours ago, Peter Drew said:

I like the AZ3, I have two.  I wouldn't buy an alt-az mount that didn't have manual slow motions and at their price the AZ3 is a bargain.  The out of balance issue is relatively easy to DIY address.  I use an AZ3 exclusively for solar observations with small Ha telescopes, an easy method I have found to cure the out of balance problem is to wrap one end of a bungee strap round the front of the OTA and the other end to somewhere on the tripod.  If you use enough tension on the strap to hold the telescope horizontal then as the telescope raises so does the tension on the bungee.  This leaves the system in equilibrium and nicely controlled by the slow motions.  🙂

 

I'd thought about playing with a bungee in that way.  To me it seems a better idea than lugging counter weights about. I can't see your quoted bits on my phone... I'm hoping it's a photo of your elasticated set up!

Yes I probably ought to give it a chance and do the stuff I've read improves it. 

-dismantle, clean the synta 'grease' off and replace with a bit of lithium or copper grease 

- play with bungees

- if backlash is a problem washers can be added in various places to remove excess play

-a new nylock nut

[LondonNeil]

Rusted, the usual way to do it is a threaded bar screwed into one of the existing tapped holes in the mount head near the front ring attachment and kinked so that it extends down and forward at about 30 degrees with the tube horizontal.   Fine balance is achieved at any given altitude of target by cw size or position on that bar. So yes,  it can be modded to work and I should have a play and give the head another chance. 

[LondonNeil]

If the mount were to be modded to incorporate a torsion spring around the altitude pivot,  that could work and would be very neat.  How to do that as a post production mod is not immediately obvious though and no doubt not easy.

[Rusted]

20 minutes ago, LondonNeil said:

Rusted, the usual way to do it is a threaded bar screwed into one of the existing tapped holes in the mount head near the front ring attachment and kinked so that it extends down and forward at about 30 degrees with the tube horizontal.   Fine balance is achieved at any given altitude of target by cw size or position on that bar. So yes,  it can be modded to work and I should have a play and give the head another chance. 

For lightweight OTAs the single weight on a kinked arm makes sense.
Tripod clearance is only an issue pointing near the horizontal.
The steeper the altitude pointing angle the more clearance is achieved.

Some Manfrotto camera heads have a torsion spring.
I found mine totally inadequate away from the horizontal.

The so-called gimbal heads are vastly better with heavier loads.
The OTA carrier can usually be fine adjusted vertically to be neutrally balanced in the vertical plane
Ironically the gimbal head creates clearance problems with increasing altitude.
I used my gimbal head for solar with my very heavy Lunt 60MT and 90mm spotting scope.
The gimbal heads do not provide slow motions but have dropped considerably in price.
FLO does not list gimbals heads but I recommend them where slow motions are not needed.

[John]

Here is an interesting article on modifying the AZ-3 mount by Antony McEwen of the Highlands Astronomical Society:

Highlands Astronomical Society | AZ-3 Mount Mod (spacegazer.com)

And he has written one on generally servicing the AZ-3 as well:

Highlands Astronomical Society | AZ-3 Servicing (spacegazer.com)

[Ags]

I had an AZ3 once. I was glad to see it gone.

[LondonNeil]

Are the gimbal heads the yoke type design often seen on cheaper scopes?  Mechanically they are so much better! I guess they are a bit bulkier and need to be sized to the tube diameter but the CoG can then be coincident with the alt pivot. 

[LondonNeil]

1 hour ago, John said:

Here is an interesting article on modifying the AZ-3 mount by Antony McEwen of the Highlands Astronomical Society:

Highlands Astronomical Society | AZ-3 Mount Mod (spacegazer.com)

And he has written one on generally servicing the AZ-3 as well:

Highlands Astronomical Society | AZ-3 Servicing (spacegazer.com)

Yes,  I'd seen those.  I'm sure it works well.  I've seen others do similar with a counter weight set up.

[John]

1 hour ago, Ags said:

I had an AZ3 once. I was glad to see it gone.

They are a compromise but can be picked up for around £50 used here including the tripod, sometimes less. With a bit of modding they can do a decent job with a small, short scope.

Not everyone wants to spend £hundreds on a grab and go mount so at least they have an option 🙂

[Ags]

It was nice and stable with my ST80 and was what I could afford at the time. However I hiked around Nepal with it, which might explain my antipathy. 

[LondonNeil]

1 hour ago, John said:

They are a compromise but can be picked up for around £50 used here including the tripod, sometimes less. With a bit of modding they can do a decent job with a small, short scope.

Not everyone wants to spend £hundreds on a grab and go mount so at least they have an option 🙂

I'm surprised they fetch £50 but the tripod seems fair and the mount in sure is fine with smaller tubes.   I'll have a think..... mod mine too improve it,  or stick it in the classifieds (a bit lower than £50 and hope it is of use to somebody)