Astro-Physics 6 inch f /12 APO

Astro-Physics 6 inch f /12 Super Planetary Triplet APO Refractor

AP_6in_f12_OTA_finder.jpg My current optical tube assembly (OTA) was first owned by master optician Thomas Back in 1987. Mr. Back confirmed to me that this scope had the same serial number as his and that "Roland [Christen, the designer] told me it had the NASA glass [KzFS-1 in the center element], and that it made it the best of the Super Planetary apos". Mr Back also confirmed that it had the blue coated cast 2.7" focuser, with ultra flat black velvet (added by himself) to the dew cap for maximum contrast, and that it had the optional compression ring adapter.

Full size 1344x937 pixel version of picture at left with University 8x50: AP_6in_f12_OTA_finder.jpg
Full size 1503x855 pixel version of picture at left
without dewshield!: AP_6in_f12_OTA_2.jpg
Full size 877x703 pixel version of picture below with slide-on dewshield of equal 7 inch OD to that of the OTA: AP_6in_f12_dewshield.jpg

The 6 inch f /12 scope is currently mounted on my Astro-Physics AP 900GTO mount in tandem with an Astro-Physics Starfire 102 f /8 APO.  See my astronomy home page for jpg photos of the complete setup.  Both of these Astro-Physics APO scopes are in fine condition and put up really nice images free of false colors.  The 6 inch f /12 Super Planetary in particular (with its huge 1828 mm focal length) when combined with a Pentax SMC 0.965 inch O-6 (6 mm) ortho eyepiece puts up a very sharp image at 1828mm/6mm = 305x magnification (about 51x per inch) even in mediocre seeing.  And the long focal length allows for greater image scale than a typical 6 inch refractor with any given eyepiece.

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Last Modified: December 7, 2012
Dale Alan Woodside (
Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 by Dr Dale A. Woodside