Altair Astro 6” Ritchey Chretien review. I have seen many people propose this scope as a possible purchase for either longer focal length DSO or planetary imaging, but I have yet to see anyone who has bought one post a detailed review. So, I thought I’d put my thoughts together after 9 months of owning this scope. This same OTA is available under several different badges including GSO, Astro Tech and Altair Astro. Altair Astro market this as a 1370mm f/9 astrograph priced very reasonably at