I have been working some guiding issues with the PHD2 folks. Their software reports the image scale of the ST-i when guiding through the kit's cctv 100mm lens as "15.26 arc-sec/px". It is their stated opinion that this scale is too rough and is "ridiculous". I have not been dissatisfied with the performance of this guiding solution (I attach the kit to a TMB80 SS piggybacked on a Meade LX200). However, the ST-i probably won't last forever. I would like to know SBIG/Diffraction Limited's recommendation for a proper imaging scale for a guiding camera. --Pieter Strauss PS when imaging through the LX200 itself, I guide with the ST-i mounted in the 8300 OAG.