Based only on my personal experience, are Carl Zambuto, who no longer sells to individuals, and Richard Wessling, of The Pines Optical Shop, in Milford Ohio,who does sell to individuals.
Wessling does all the work himself, so your mirror gets individual attention. He has made large and small Newtonians, and also Classical Cassegrains, Herschelians, Shiefspieglers, Tri-Schiefspieglers, Yolos, and many unusual and demanding designs, some of them using toric and other aspeheric mirrors. A truly outstanding mirror maker.
I have a Zambuto (in an 11 Starmaster) and two Wessling mirrors, 10 and 6 inches, and all three are outstanding.
Bill Meyers
Wessling does all the work himself, so your mirror gets individual attention. He has made large and small Newtonians, and also Classical Cassegrains, Herschelians, Shiefspieglers, Tri-Schiefspieglers, Yolos, and many unusual and demanding designs, some of them using toric and other aspeheric mirrors. A truly outstanding mirror maker.
I have a Zambuto (in an 11 Starmaster) and two Wessling mirrors, 10 and 6 inches, and all three are outstanding.
Bill Meyers