Feather Touch 90mm x 1mm pitch adapter to put Feather Touch Focuser on Astro-Tech AT8RC astrograph

In such rare cases, the standard Crayford focuser can be user-replaced by an optional Feather Touch #FT-1.5BC 2" focuser from Starlight Instruments for a more rigid imaging equipment connection. This 90mm x 1mm pitch Feather Touch adapter is needed to connect the #FT-1.5BC to the #AT8RC. The adapter threads onto the 90mm rear cell thread of the #AT8RC in place of the standard Crayford focuser. The Feather Touch #FT-1.5BC focuser slips into the adapter and is held in place by three hex-head setscrews in the adapter.

Only focusers with a maximum 1.5" drawtube travel, such as the Feather Touch #FT-1.5BC, are recommended with the Astro-Tech #AT8RC 8" Ritchey-Chrétien.

This adapter and the Feather Touch #FT-1.5BC focuser can also be used with the 6" #AT6RC Ritchey-Chrétien astrograph. However, the #AT6RC is primarily designed for use with lighter weight webcam/Deep Sky Imager-type camera/DSLR imagers, not with heavy long equipment train CCD imaging setups. These lighter weight imaging systems are unlikely to cause any focuser issues. The addition of a Feather Touch focuser and this adapter will add little to the performance of the #AT6RC, although significantly to the cost (about half the cost of the #AT6RC itself).