Rowan AZ100 Mount Owners Thread

[Stu]

9 minutes ago, Split Zygote2 said:

I have adopted this approach to fully balance the scope in all axes and it works well for me (hopefully the picture will upload or you will all be

mightily puzzled) The 90 degree offset of these particular dovetail clamps is achieved without modifying either the mount or the clamps.

The Losmandy dovetail however has had a couple of extra holes drilled in it to attach the flange which  holds the counterweight bar.

 

With this arrangement I can routinely mount refractors of up to 20 kilos all up weight with an additional 15 to 20 kilo of counterweight. If correctly

adjusted the scope and binoviewers will stay exactly where you put them with all clutches completely disengaged as the offset of the weight with

respect to the horizontal axis of the mount balances the offset of the binoviewer load with respect to the centre line of the OTA. Without this

arrangement I have to tension the clutches significantly  to overcome the imbalance!  When correctly set up, using this weight offset approach,  a

sweet spot can be found where the scope can be moved precisely with  one finger and without further adjustment the slow motion controls can

also be employed.

 

With care (scope vertical) the adjustment of the the weight offset is practical in the  field and I have inscribed a rule on  the dovetail to aid in this.

A stop bolt to prevent the weight sliding through the clamp when the scope is horizontal is also a very good idea. The Rowan clamps are most

excellently engineered and any slippage would be the result of user error but given long enough user error will almost inevitably occur.
 

It is possible to extrapolate from this and produce an arrangement where the scope rather than the counterweight is offset from the horizontal

axis of the mount (as in the Nova Hitch). I have made up a separate dovetail plate for doing this. I use this approach for shorter lighter scopes

(TV85, a counterweight is unnecessary) where an Ethos and Powermate used in combination causes similar balance issues. Indeed completely

balancing a TV 85 before this approach on any alt/az mount that I tried ( 4 in all including TeleVue's own before the AZ 100 came along) was all

but impossible

That’s a clever solution 👍. You are right, without a picture I would never have worked that out 😀

[Split Zygote2]

The alternate approach: lowering the scope in relation to the horizontal axis; in this case by not so much as the imbalance with a regular eyepiece and diagonal is not so great but if you look carefully the offset of the scope to the horizontal axis of the mount becomes apparent.  Note the Baader steel counterweight on the other side of the mount is to adjust the fore and aft balance of the refractor and is not primarily intended as a counterweight. Think I may have sorted the formatting issue of my previous post - user error again although it must be said that it didn't leave this end in such a muddle!

[Stu]

10 minutes ago, Split Zygote2 said:

The alternate approach: lowering the scope in relation to the horizontal axis; in this case by not so much as the imbalance with a regular eyepiece and diagonal is not so great but if you look carefully the offset of the scope to the horizontal axis of the mount becomes apparent.  Note the Baader steel counterweight on the other side of the mount is to adjust the fore and aft balance of the refractor and is not primarily intended as a counterweight. Think I may have sorted the formatting issue of my previous post - user error again although it must be said that it didn't leave this end in such a muddle!

I can see why you wouldn’t want to do it that way (more risk to the scope I guess), but it certainly looks simple and effective. I’m sure Rowan could come up with something that achieves this.

[Split Zygote2]

AND finally solution no.3 (leaving no stone unturned is a character flaw I am afraid) . Same set up as my previous post with the clamps offset by 90 degrees but re-arranged to provide some horizontal counterbalance with the weights this time lowered with respect to the mounts horizontal axis rather than the scope - obviously fewer weights would require more lowering. The simplest most elegant solution requiring only one extra dovetail plate and  no drilling. The fore and aft balancing of this particular scope with a 31mm Nagler at the back is problematic hence my preferred solution is in my 2nd post, note in this context an AZ4, Ercole or even TeleVue's own alt/az offered only a partial remedy.

As regards as whether to offset the scope or the weights... Any scope gets exponentially heavier in relation to its price - a scope of 10 kilos costing £20 a kilo is way lighter than a 10 kilo scope costing £100s per kilo. Sliding such a scope up and down in the dovetail with cold fingers in the dark seems to me to be an accident waiting in the wings. Falling counterweights are always less of an issue broken feet or little heads notwithstanding!

I have already dropped a few hints to Rowan but they are quite understandably busy with more pressing priorities. 

[Stu]

34 minutes ago, Split Zygote2 said:

AND finally solution no.3 (leaving no stone unturned is a character flaw I am afraid) . Same set up as my previous post with the clamps offset by 90 degrees but re-arranged to provide some horizontal counterbalance with the weights this time lowered with respect to the mounts horizontal axis rather than the scope - obviously fewer weights would require more lowering. The simplest most elegant solution requiring only one extra dovetail plate and  no drilling. The fore and aft balancing of this particular scope with a 31mm Nagler at the back is problematic hence my preferred solution is in my 2nd post, note in this context an AZ4, Ercole or even TeleVue's own alt/az offered only a partial remedy.

As regards as whether to offset the scope or the weights... Any scope gets exponentially heavier in relation to its price - a scope of 10 kilos costing £20 a kilo is way lighter than a 10 kilo scope costing £100s per kilo. Sliding such a scope up and down in the dovetail with cold fingers in the dark seems to me to be an accident waiting in the wings. Falling counterweights are always less of an issue broken feet or little heads notwithstanding!

I have already dropped a few hints to Rowan but they are quite understandably busy with more pressing priorities. 

Out of interest, do you use the slow motion controls? I’ve not found these sorts of things necessary with the AZ100 with clutches engaged even with a 31mm Nagler fitted.

[Split Zygote2]

Yes and no.

With longer scopes I do not,  I just grab the diagonal as there is obviously a longer lever which confers more control. In truth I wouldn't engage the clutches at all but there is both the wind and your eye sockets which together conspire to move you off target - focusing also. So I use the minimal clutch tension that ameliorates these issues. This happens to be enough to enable the slow motion controls as well. I do find that for seamless operation  I have to play with the dampening controls a little even for use without the slo-mo (regardless of what it says in the manual)

With the TeleVue I have started to use the slo-mo controls with custom cut down cables which Rowan are happy to supply. A radial movement of say a centimetre at the focuser end with a small scope will move you off target more than the same centimetre movement when using a longer scope. Having said that I dislike slo-mo controls but probably because I am not all that used to them.

As I am sure you know the slo-mo controls are helpful moving the scope when pointed  at the zenith - not so much leverage from the scope. You cannot cuddle a refractor in the same way that you can cuddle a Dob to move it when pointed straight up .... and would you even want to?  The optional handle for the AZ 100 may help with short tubes but unless it can be mounted other than directly in line with the dovetail clamp (i.e. at an angle like the AZ4) then its assistance viewing the zenith would be marginal.

[swsantos]

8 hours ago, Stu said:

Of course yes, I agree that is a more elegant solution. Just so I understand, it involves being able to adjust the position of the scope vertically (when horizontal) with reference to the Alt axis? It may be something Rowan can look in to.

Yes. Here is a stock picture of the back of the Nova Hitch's saddle where you can see the up / down sliding mechanism built right into the mount that provides the two axis balancing. There are two other vertical slots with tightening thumbscrews on the front side of the saddle as well. It would be easy to produce an interface add on like the altitude adjuster to do this. I have reached out both to Rowan and ADM about this idea and I think its a good one but Rowan is understandably busy getting the tracking straightened out. Still I feel that this would add a unique and very useful adjustment and produce another add on that we can purchase from them.

Also notice that small platform on the top of the saddle. It is a finder platform attached to the top so that the finder is on the mount and not on the telescope which I think is another brilliant feature of the Nova Hitch and that could be incorporated into and AZ100 somehow.

I have also attached a picture on my Nova Hitch to see it all in action.

Edited February 6, 2022 by swsantos

[Sunshine]

11 hours ago, Stu said:

We should be getting the final iteration with some useful improvements to test within a couple of weeks so hopefully it’s getting close now. Not sure of exact dates though.

These had to wait for the machines to finish the AZ75 parts first but hopefully are next up to be worked on.

What will the weight capacity be for the AZ75 and will it have slow motion controls too? it seems the AZ100 has slow motion controls.

[bsdsgl84]

5 minutes ago, Sunshine said:

What will the weight capacity be for the AZ75 and will it have slow motion controls too? it seems the AZ100 has slow motion controls.

There is separate thread covering the AZ75 mount - maybe ask there? 

bsdsgl84

 

[Stu]

16 minutes ago, Sunshine said:

What will the weight capacity be for the AZ75 and will it have slow motion controls too? it seems the AZ100 has slow motion controls.

I don’t wish to go round that awful loop again, the counselling is just starting to have an effect (🤪), but to confirm it will NOT have slow motion controls. The motion is very smooth even without them. Please do not start another discussion around this.

Not totally sure of the load capacity, quite possibly 15kg, it has taken my 130mm LZOS with ease which is quite a lump. It will have encoders as an option, just the same as the AZ100 for linking to SkySafari etc.

[Sunshine]

16 minutes ago, Stu said:

I don’t wish to go round that awful loop again, the counselling is just starting to have an effect (🤪), but to confirm it will NOT have slow motion controls. The motion is very smooth even without them. Please do not start another discussion around this.

Sure no problem, I wasn't aware you have been fully saturated with this question already 🤣 

[Space Hopper]

5 hours ago, swsantos said:

Also notice that small platform on the top of the saddle. It is a finder platform attached to the top so that the finder is on the mount and not on the telescope which I think is another brilliant feature of the Nova Hitch and that could be incorporated into and AZ100 somehow.

I have also attached a picture on my Nova Hitch to see it all in action.

 

This is also a feature on the US made DM-6.

I've always preferred having my finder on the mounts altitude axis , rather than on the telescope.

I don't think there's much room for such an arrangement on the AZ100 though ?

 

[johninderby]

Would be quite easy to fit a finder shoe with a flat bottom to the top of the saddle although I would get a bit of 1” x 4” ali angle and fit it between the saddle and mount to avoid drilling the saddle.

BTW I prefer my finder on the scope. 🙂

Edited February 6, 2022 by johninderby

[Speedmaster]

Thanks to all of you for your valuable inputs. 

To be more specific, here is how I use the mount. I believe I know the basics: alt lock is never engaged in a session. Only for blocking the scope when changing EP or installing/uninstalling the scope. 

 

The clutches are there to adjust the friction on both axis and therefore to give more « weight » to the movement and to block some movement due to slight unbalance . 

For me, the problem is with the alt axis. The az axis is very smooth. I use only a very slight adjustment on the clutch. 

 

The alt axis clutch is never fully loose. More often is pretty tight because of this unbalance with the bino. with a diagonal it feels much more light and only requires a small touch on the clutch. 

With the bino it can have a small touch on the clutch but as it approaches zenith it needs more and more pressure on the clutch. Which I understand is normal because of the large offset due to the bino. 

Anyway movement by hand is fluid and smooth but not THAT smooth as with the clutches totally loose.

 

But do some people really achieve perfect balance with all clutches off, at all angle And without any additional weights or accessory? Don’t think so…

 

Slo mos are used without much problems (and only when alt lock is disengaged). With clutches loose (when It can) and with clutches tightened to keep the scope balanced. Is there a range where they work better? Damping adj are always in the 0 position (position just before feeling the blocking of the thread)

 

Only issue I found with slo mo is some stuttering on the alt axis when the adjusters are set to this 0 position (almost tight). When I fully tight both, the stutter is gone but I get a small dead zone where I turn the slo mo wheel but I get no movement. I have to keep turning it to have movement. 

[Stu]

2 minutes ago, Speedmaster said:

But do some people really achieve perfect balance with all clutches off, at all angle And without any additional weights or accessory? Don’t think so…

On this specific question, I would say no. No matter how good the mount, with clutches totally off a scope with binoviewers will not stay put when pointed up towards the zenith without additional counterweight offset at the front. It’s just basic physics, not a fault with the mount. With clutches tightened then the slo motion controls work fine for me so that’s how I tend to use it at those altitudes.

[Space Hopper]

3 hours ago, Stu said:

On this specific question, I would say no. No matter how good the mount, with clutches totally off a scope with binoviewers will not stay put when pointed up towards the zenith without additional counterweight offset at the front. 

Hmmmm......🙂

[Stu]

1 minute ago, Space Hopper said:

Hmmmm......🙂

Is that a ‘hmmmm’ disagree, or… something else?

[Deadlake]

4 hours ago, Stu said:

On this specific question, I would say no. No matter how good the mount, with clutches totally off a scope with binoviewers will not stay put when pointed up towards the zenith without additional counterweight offset at the front. It’s just basic physics, not a fault with the mount. With clutches tightened then the slo motion controls work fine for me so that’s how I tend to use it at those altitudes.

I agree this is basic physics. Within a certain weight change I can see a rebalance is not required, however adding a BV to the scope then I just accept that I need to rebalance the scope or need a weight to change the balance. 

[Stu]

48 minutes ago, Deadlake said:

I agree this is basic physics. Within a certain weight change I can see a rebalance is not required, however adding a BV to the scope then I just accept that I need to rebalance the scope or need a weight to change the balance. 

Thing is, for perfect balance, the weight needs to hang down below the level of the dovetail otherwise when at the zenith the binoviewers still pull the scope backwards. It doesn’t matter how far forward you push the scope, you need the balancing weight below the dovetail.

[Stephenstargazer]

Balancing scopes, eyepieces and binoviewers in both axes is well discussed above.  If you are interested in an off the shelf solution using a sliding weight that will fit the opposite side of the mount, see this:

http://www.desertskyastro.com/QBS.html

I had one of these and wished I kept it when I sold the mount! The bar the weight slides on slopes down (adjustable) so as you slide it forward it also gets lower. On my AZ100 I use a small weight below the axis. The bar it's on has a few holes drilled for adjustment and it can balance a binoviewer.

 

Edited February 8, 2022 by Stephenstargazer
add pictrures

[Sunshine]

6 hours ago, Stu said:

On this specific question, I would say no. No matter how good the mount, with clutches totally off a scope with binoviewers will not stay put when pointed up towards the zenith without additional counterweight offset at the front.

This I learned first hand while using my scope on my new (to me) alt azimuth mount which I have very little experience with alt-az mounts to boot. While I thought I had the scope perfectly balanced, when I pointed close to zenith (clutches off) with my heavy XW's, to my surprise the scope drifted further downward rather easily. An unavoidable trait of alt-az mounts it seems, I guess counterweights would remedy the situation but would they not then create an imbalance on another orientation?, interesting stuff.

Edited February 8, 2022 by Sunshine

[RobertI]

On 06/02/2022 at 10:05, Split Zygote2 said:

I have adopted this approach to fully balance the scope in all axes and it works well for me (hopefully the picture will upload or you will all be

mightily puzzled) The 90 degree offset of these particular dovetail clamps is achieved without modifying either the mount or the clamps.

The Losmandy dovetail however has had a couple of extra holes drilled in it to attach the flange which  holds the counterweight bar.

 

With this arrangement I can routinely mount refractors of up to 20 kilos all up weight with an additional 15 to 20 kilo of counterweight. If correctly

adjusted the scope and binoviewers will stay exactly where you put them with all clutches completely disengaged as the offset of the weight with

respect to the horizontal axis of the mount balances the offset of the binoviewer load with respect to the centre line of the OTA. Without this

arrangement I have to tension the clutches significantly  to overcome the imbalance!  When correctly set up, using this weight offset approach,  a

sweet spot can be found where the scope can be moved precisely with  one finger and without further adjustment the slow motion controls can

also be employed.

 

With care (scope vertical) the adjustment of the the weight offset is practical in the  field and I have inscribed a rule on  the dovetail to aid in this.

A stop bolt to prevent the weight sliding through the clamp when the scope is horizontal is also a very good idea. The Rowan clamps are most

excellently engineered and any slippage would be the result of user error but given long enough user error will almost inevitably occur.
 

It is possible to extrapolate from this and produce an arrangement where the scope rather than the counterweight is offset from the horizontal

axis of the mount (as in the Nova Hitch). I have made up a separate dovetail plate for doing this. I use this approach for shorter lighter scopes

(TV85, a counterweight is unnecessary) where an Ethos and Powermate used in combination causes similar balance issues. Indeed completely

balancing a TV 85 before this approach on any alt/az mount that I tried ( 4 in all including TeleVue's own before the AZ 100 came along) was all

but impossible

I have a similar solution for my small G&G setup - put together from spare parts, but it works very well! 

Edited February 8, 2022 by RobertI

[Sunshine]

Brilliant!

[swsantos]

11 hours ago, Stu said:

On this specific question, I would say no. No matter how good the mount, with clutches totally off a scope with binoviewers will not stay put when pointed up towards the zenith without additional counterweight offset at the front. It’s just basic physics, not a fault with the mount. With clutches tightened then the slo motion controls work fine for me so that’s how I tend to use it at those altitudes.

When your telescope is pointed straight up with a binoviewer and looses balance it is because it is not balanced on the Y axis..  

Looking at a telescope pointing upwards, the side with the binoviewer or eyepice is heavier than the side without it when they are sticking out of the diagonal. With a diagonal pointing up + eyepiece or binoviewer + finder on the top > the telescope is begging for Y axis balancing.

If one was able to move the telescope from one side to the other with it pointing upwards you could balance it on the Y axis. That is either achieved by lowering the telescope in the saddle (moving it to the right in the picture below) or by using a counterweight not on the front of the telescope but under the telescope.

I have attached a picture of another of Charles Riddel's mounts, the Half Hitch, which also had two axis balancing and this picture illustrates what I mean.

 

 

Edited February 9, 2022 by swsantos

[Stu]

6 hours ago, swsantos said:

When your telescope is pointed straight up with a binoviewer and looses balance it is because it is not balanced on the Y axis..  

Looking at a telescope pointing upwards, the side with the binoviewer or eyepice is heavier than the side without it when they are sticking out of the diagonal. With a diagonal pointing up + eyepiece or binoviewer + finder on the top > the telescope is begging for Y axis balancing.

If one was able to move the telescope from one side to the other with it pointing upwards you could balance it on the Y axis. That is either achieved by lowering the telescope in the saddle (moving it to the right in the picture below) or by using a counterweight not on the front of the telescope but under the telescope.

I have attached a picture of another of Charles Riddel's mounts, the Half Hitch, which also had two axis balancing and this picture illustrates what I mean.

 

 

Yes, you are just confirming what I said.

That system looks like a good solution; I should have clarified that I was stating that a mount that has the scope in line with the axis can’t stay put with clutches fully released. With an offset mechanism it clearly can.