Confused about weight limits for EQ vs alt-az mounts and tripods

[Giles_B]

I've just dusted off my Celestron 130AZ Newtonian and started doing a little solar observation. The scope comes with an alt-az mount and tripod, but having come back to it after many months of using a larger dob, I've noticed it gets very wobbly at high magnifications, even in still conditions - just touching the focuser gets it shaking for a good 30 seconds. I guess that a new mount and tripod might help this? Indeed, it would probably make any upgrade to a refractor (specifically for solar) less painful too.

Now, in my fantasy upgrade plan (not privy to my partner or bank manager) I'd always expected I'd want a bigger alt-az mount and tripod so I had the option of mounting my larger 10" Dob, which weights 11kgs. Alas, I've parked the idea some time ago, because it seems I'd need a £1000 HEQ5 to handle this weight, and also because my current OOUK dob base is very smooth and has largely eliminated the need for fine tracking controls.

Now I'm thinking about mounts again, I'm confused as to whether the weight limits given for EQ mounts would apply to an alt-az setup (I'm not interested in imaging, so can't imagine why I'd need an EQ mount), but there don't seem to be any "big" alt-az mounts. Why? Is the limiting factor for alt-az mere stability, rather than whether a motor can support the weight of the OTA? or is it just that there is no demand (is there some reason to go for EQ that I'm not considering)? or have I got a bit confused about the whole business? I'm guessing it's probably the latter, and would really welcome some help!

 

[Elp]

There are weight limits on alt az mounts, most heavy duty ones allow counterweights to be added for balanced loading. I also think the term mount is kind of mislabelled, the mount in my opinion should refer to the head (what you mount the telescope to) and the tripod should be referred to separately. Most shaking I've found is down to the tripod, not the head, a sturdy tripod tends to fix this. A sturdy mount fixes any motion issues.

You mentioned a dob, I'm not experienced with them but don't they have their own specific platforms for mounting onto, rather than mounting onto a typical tripod/alt az/EQ head due to their size?

Are you also after goto or manual?

[happy-kat]

I think I saw it along the lines of if sticking with a large  newtonian the user would need an even taller ladder for seeing into the eyepiece or a very deep wallet for a very fast shorter tube newtonian if using a tripod.

Tripods are generally more stable if used without the legs fully extended.

Dobsonian is named after the person who designed the base and sat a newtonian (reflector) telescope on it.

Edited July 22, 2022 by happy-kat

[Giles_B]

Thanks for the clarification on where the wobble might come from - looks like a tripod is what is needed first and foremost - indeed, the legs were retracted in an effort to get more stability, but all in vain.

I think I'm generating more confusion about the 10" newtonian, so I'll try to explain a bit: I have a second-hand OOUK VX10 which is mounted on a dobsonian base (and very good the base it is too). In the past my experience with dobsonian bases has been that it is often very hard to track planets at high magnifications. The VX10 has a dovetail so can be mounted on a tripod - indeed Orion Optics allow this customisation (but with an EQ5M mount) at point of sale. I don't need go-to, and I don't need EQ.

So I'd like this advice: what ALT-AZ mount would take this (11kg) weight, and, ideally what tripod it should be paired with.

If I should then get a new mount (for whatever OTA or reason), with this information I will know if I have an option to mount the VX10 upon it (tall ladders not withstanding - the OTA is 1200mm, so not so big).

Edited July 22, 2022 by Giles_B
added information

[Cosmic Geoff]

I think there is very little demand for larger manual alt-azimuth mounts other than Dobsonian for newtonian reflectors because the scary price tag soon sends prospective buyers running in the direction of a Dob with its economy chipboard mount.

If you want to spend your money, I saw a nice series of alt-az mounts at an astronomy show, which had digital setting circles or GoTo as an optional extra. The Rowan AZ-100 takes plenty of weight on each side for a mere £1049. (tripod and accessories extra)

In the smaller mount sizes there seem to be a number of alt-az offerings from SkyTee etc.

As for tripods, the 2" gauge tripods used with the Skywatcher EQ-6 mounts should be adequate.

[Elp]

I was looking at relatively heavy but light and compact alt az mounts and really liked the look of the Stellarvue m2c as it also got great reviews but due to importing it it became expensive, I ended up getting a Technosky Cubo which also allows to add counterweights for up to 12kg loads. Above that weight range not really sure as you'll likely need something beefier, other people can offer their advice, doing a quick look the Rowan's certainly fit the bill but at a price, also the Berlebach Omega.

Speaking of Berlebach, their tripods really are good. I've got a uni 4 and it's payload is something like 60kg, it's so sturdy it would likely take my weight and stand firm without moving if I sat on it (though I wouldn't try it), dampens very quickly too.

Edited July 22, 2022 by Elp

[Alan White]

Bigger Alt AZ are around and available, the Rowan AZ100, The APM MaxLoad, Track The Stars  etc.
Because of the qulity engineering they cost more than some hope, you do get what you pay for in this hobby.

The issue now is that astronomy has biased towards imaging, not us visual obserevers and the market feeds the bigger demand.
Imagers if you look spend a Princely Sum on mounts before they even start erally spending, 
but for imaging its equatorial mounting, so the visual alt az is less well served.

I can see why larger newtonians are mounted on dobson mounts, but I did find that a frustration at higher powere and the difraction spikes, just messed with my head too much, so I am just a refractor only observer now and accept my lot for the spike free view,
mind you one day I hope for a 5" or 6" refractor.

[CraigT82]

The skytee II might just about handle it but would want a better saddle clamp and a burly tripod, and probably a motorised focuser too. I doubt it would be any smoother than the dob mount though so not really and upgrade at all.

Spending more you could look at the Rowan AZ100 which should handle the 10” beautifully. Neve used on myself but by all accounts they are wonderfully made and very sturdy.

I use an AZ-EQ 6 in alt az mode to mount my 12” newt…Works fine but I do have a motorised focuser which, along with the motorised tracking means that I don’t have to touch the scope at all so the only wobbles comes from wind gusts. 

 

[wookie1965]

I use a Eq6 tripod with adapter plate with a EQ5 head and it is rock solid even with a 5" refractor on. 

[AstroMuni]

2 hours ago, Giles_B said:

Now I'm thinking about mounts again, I'm confused as to whether the weight limits given for EQ mounts would apply to an alt-az setup (I'm not interested in imaging, so can't imagine why I'd need an EQ mount), but there don't seem to be any "big" alt-az mounts. Why?

One reason I can think of is that an EQ mount can be readily converted to an AZ mount. Read this post

 

[ollypenrice]

I agree that the EQ mount only makes sense, these days for imaging. If you want motorized tracking you can have it in alt-az mode with more convenience, thanks to the inboard computing available. I don't think the sales bias towards imaging has much to do with the rarity of large Alt-Az mounts. Rather, it's the efficiency and economy of the Dobsonian Alt-Az mount which has undermined the engineered, metal Alt-Az. For my money the Dobsonian Alt-Az is both better and cheaper than many metal-and-balbearing alternatives. This set me thinking that most solar observers at mid and high latitudes could make a variant of the Dobsonian for refractors, since the range of elevations would be quite limited. No need to approach the zenith.

Edit: I've used a GEM in Alt Az simply by pointing the polar axis straight up, as you would polar align it at the north pole. After all, that's what an Alt-Az mount is: an equatorial aligned for N polar observation. (As for N. Polar observation, all I'll say is, 'After you!') 😁 

Olly

Edited July 22, 2022 by ollypenrice

[TheycallmeRiver]

There is an AZ-EQ 5 which has just been posted on UKABS, including tripod and hand controller for £700.  I know that’s still expensive, but it’s a lot less than the £1000 option you vetoed and should do what you want it to do payload wise if you use it in AZ. 

Plus, you’re a little future proofed if decide you fancy trying some astrophotography further down the line.

I figured along similar lines when I bought my used AZ EQ 6 recently. 
 

https://www.astrobuysell.com/uk/

[Giles_B]

@Elp the Technosky Cubo  looks like great value, and is definitely a great tip. Thank you.