I wont comment on the apo move but I will say my DM6 comfortable limit is 130-140mm. That is, if youre using the DM6 with extension. The scope is at face height so holding a scope with dovetail into the saddle is a bit of work.
I agree with this and in the deep sky observing section posted a picture of the rig I was using which I considered to be a bit excessive for my DM6. It was a 130 mm with a 92 mm mounted on top except on the DM6 the top is on the side. nothing bad happened but I wasn't completely comfortable with the stability.
130 mm for the DM6 seems about right to me. The owner of the company seemed to think I should have gotten the DM4 for the 130 millimeter. My standards for stability have been set by the two decades of using the Losmandy G11. So the truth is I'm happiest using a 92 mm on my DM6.
All of this with the extension for extra height.
The configurations I use on the DM6 are stable but I don't really like having all that weight on one side. All it would take is an accidental lean or bump if the scope was in the wrong position for the system to lose its balance. This is particularly true if the shock in the opposite direction of an extended leg.
If you're observing on grassy surface and you have the surveyor points on your tripod, which are an option both with the tpod and with the berlbach then the stability would be much greater. I would consider 160 mm in that case but I wouldn't be happy about it.
The owner of the company has much more optimistic views about the maximum capacity of his mounts.
The other thing to remember is that as the scope gets bigger the balance gets to be more critical. The moment arm on that 31 mm nagler will be much greater on a 180 mm telescope than on a 92 mm telescope. The result of this is that you may have to operate them out with higher tension on the clutch which makes for less smooth and more jerky manipulation of the telescope.
I will say that in general alt az mounts have been disappointing in my personal experience and that the DM6 is the best I've seen. So I'm not sorry that I have it. The value returned for the money spent is good. It does provide a quick setup which is what I wanted it for and it is stable with the scopes I use it on. But I wouldn't mount a C14 on it sideways and by the same logic I certainly wouldn't mount a 180 mm refractor that cost four times more.
Edited by gnowellsct, 24 September 2020 - 07:05 AM.