Considering assembling a dob in the range 10"-13" aperture, either using a Royce or Zambuto mirror. Was considering ordering one (I know there is a long queue for Zambuto) and that there's both a 12" f/6 Zambuto and a 10" f/8 Royce on CN. Anyone like to say whether they would prefer a mirror from Royce or Zambuto, and why ?
PS don't tell me about bigger mirrors - as there is a serious space constraint.
There's a lesser known mirror maker called Waite Research LLC. People who have done side by side comparisons say they can't tell the difference between Zambuto and a Waite Research LLC mirror. I believe the wait times are also considerably shorter.
I have a 14"/F4.5 Zambuto mirror and it is exceptional. I have also used a couple of other Zambuto mirrors and they have been exceptional. Only used one Royce mirror and it was excellent.
That having been said they all make mistakes occasionally and produce something which leaves something to be desired, however the failure rate on behalf of both mirror makers, is exceptionally low, to my knowledge. I have also heard very good things about Gordon Waite, but haven't used one of his mirrors. Mark Suchting's mirrors are as good as anyone's on the planet, but I don't think he is taking orders at the moment. I have a 10"/F5.3 Suchting mirror in a miniaturised SDM truss scope which delivers stunning lunar/planetary views.
If I had the need to order another mirror (which I won't), I would order another mirror from Carl Zambuto, without hesitation.
One thing to consider is to go with the thinnest possible mirror substrate the chosen mirror maker is prepared to work with. This will be of enormous benefit in enabling the scope to reach thermal equilibrium and deliver its best performance early in each observing session. My 14" Zambuto mirror is only 1.3" thick, which is as thin as Carl Zambuto was prepared to make it. The scope delivers stunning images from early on in each observing session. My 10" Suchting mirror is just over 1" thick, which is as thin as Mark would go. Both scopes cool beautifully. The 18" Obsession with 2" thick OMI mirror takes forever to cool when the temperatures are falling.
Recently Royce changed from drilling the hole clean through the mirror to drilling a blind hole leaving the front surface intact, and filling the hole with epoxy to set a stud in that. Mechanically this is fine, I know.
What concerns me is that I know coatings don't last forever and the mirror will require re-coating. You cannot put epoxy in a vacuum chamber, which means not only must it all be removed, it must be scrupulously chemically cleaned (etched) first and that isn't easy to do for a hole (I know what is involved having watched this process first hand, a few times). It implies re-coating such a mirror could be potentially impossible, actually.
Hence inclined to go with the Zambuto over a Royce mirror.
