Have a feeling Antares sort of quietly disappeared some time ago.
Their site only seems to have a date of 2014 everywhere. Also cannot see Antares secondaries on the RVO site - they used to be the people that sold Antares items, usually eyepieces however. The other noticable item is that all the Antares site appears to have is secondary mirrors, nothing else. Which I think is a little odd.
Strange memory that they stopped the general manufacture of astronomy equipment in Canada and moved production to the far East. May have been a selling of the brand name I suppose.
Say this as there seems several retailers selling Anteres items - http://www.vectorwar...antares/new.htm
About 2/3 down it lists Antares ellipticals but they stop at 2.1". RVO list 66 items under a search for "Antares". There are several Antares items but not it seems via Antares Optical - are they the same or has some form of separation occurred.
A 1/30 flat seems high specification, also numbers for flattness seem "ambiguous".
Looked at alternatives and Edmund Optics do elipticals, maybe email Lockwood Custom Optics, another is Owl (OpticalWaveLabs). Not sure what Hubble Optics do worth looking.