Belt modding and upgrade an old EQ3-2: where to start/worth it?

[GTom]

I have a venerable EQ3-2 goto on a solid steel tripod, thought it might worth upgrading it to a level that it will be AP-capable with my heavy built 90/600 APO+heavy camera gear (total will be around 7kg).

 

Any advice on materials and what needs to be replaced? E.g. can I keep the motors (both working fine) or do I need a full belt-driven assembly with a modern hand controller? Or forget it and bring it in for a stellardrive mod ?

[Carbon Brush]

Those in the know usually say an EQ5 is pushing things for photography. An EQ3 is undersized.
I'm going on what I have seen posted. Never done photos on EQ3 and not owned one for many years.

My thought would be to look for a bigger 2nd hand goto mount/tripod to get things moving straight away.

HTH, David.

[Steve Ward]

Used my EQ3-2 for solar , lunar and planetary with no problems but wouldn't have contemplated using it for long exposures .

HEQ5 and upwards is what you need ... 😉

[Albir phil]

As said think you would be better with HEQ5 . Not sure what the cost of a belt assembly would be ,that's if you can get one,but the hand control will probably be over 120 £ . Hope you get it sorted.

[Carbon Brush]

There is an HEQ5 with belt in the classifieds.
I have no affiliation, recommendation or knowledge of the item or seller. Just seen it😁

 

[GTom]

Thank you for all the feedback, true, the HEQ5 is a solid mount, but a little on the heavy side. Before going with another mount, I'll take a closer look on the modding possibilities reported here, having a solid tripod this might be sufficient: 

 

 

[michael8554]

Hi Tom

What are you hoping to achieve with the belt mod ?

It will remove the PE from the gearbox, but the worm and wormwheel remain.

As do the stock RA and Dec bearings, which may be stiff.

And belt mods can introduce a very fast RA oscillation that is hard to guide out.

I'd future-proof by buying a much better mount.

Michael

 

[doublevodka]

On 28/07/2023 at 15:32, GTom said:

I have a venerable EQ3-2 goto on a solid steel tripod, thought it might worth upgrading it to a level that it will be AP-capable with my heavy built 90/600 APO+heavy camera gear (total will be around 7kg).

 

Any advice on materials and what needs to be replaced? E.g. can I keep the motors (both working fine) or do I need a full belt-driven assembly with a modern hand controller? Or forget it and bring it in for a stellardrive mod ?

Having previously owned one and stripped it multiple times I would say try it out as it is for now, just to get you started.

A problem with it is it doesn't have real bearings on all axis, it's effectively a shaft in a collar and can't really be changed without some serious machining. So right from the outset you are going to have a fight on your hands.

However, if you use it in the short term you can at least get a flavour for AP and see if it is for you before spending a lot more money, just don't expect multi-minute exposures.

If you really really must mod this mount, then I would suggest looking at OnStep - https://onstep.groups.io/g/main/wiki/4414 as that is about the cheapest way to give you the functions you want that I found before giving up on the idea.

[GTom]

That is a valid point, the lack of bearings could haunt the process. Reading though that the much newer eqm-35 doesn't have bearings either. Seems I need to step up to azeq5 level in case I decide to trade up.

If I get a single hour of clear sky this week, I'll test how the mount is performing in its actual state.

[wimvb]

Having used the eq3 pro with a 5 kg 150PDS and dslr, I can only confirm what others have said. I find that the small mount (with aluminium tripod!) and large Newtonian is a very odd combination to offer as a beginners astrophotography setup. But the EQ3-Pro combined with a short fl refractor, can make a very handsome travel kit.

The eq3 only has 4 bearings, and those hold the worm in place. The eq3 relies on its teflon shims in combination with "chinese black goo", aka high viscosity grease, for smooth performance of RA and DEC. Some time ago I tried to install needle bearing on the RA and DEC shafts, but they built too much. I followed this video.

A belt mod would be interesting, and could improve guiding. From my experience with the belt driven AZ-EQ6,  high frequency oscillations are mainly due to improper belt tension. You'd have to figure out the gear reduction in the current gears and source appropriate timing wheels, but then it could work with its hand controller. If you can't find the exact hardware, you'll have to make your own motor drivers.

[GTom]

Brilliant summary, many thanks!

[Coastliner]

You certainly can do dso with an eq3-2 Pro. M3, 57x60s guided, Atik 460EX, WO ZS61.