I've seen this in several manufacturer "ads" now as something special. I understand it pertains to the lack of particular optical aberrations i.e. perfect lens. Without digging into "Telescope Optics..." I'm curious if the highest quality apos like AP/TEC etc as well as maybe the D&G achromats...all of which are painstakingly figured and corrected to eliminate secondary aberrations ('cept for focal length related CA in the latter) can also be considered "anastigmatic"? My gut tells me this may be just marketing mumbo-jumbo to separate themselves from the pack and impress the impressible, or is this actually a valid optical attribute only the luckiest and most fortunate telescope users should pursue?
8" f/12 D&G classic refractor
Astro-Physics 1200 DA equatorial mount
BlueStar Observatory (roll off) by Backyard Observatories of Lodi, Ohio
Previous telescopes A-Z...Astro-Physics to Zeiss