Placement of the ATLAS temperature sensor was a weird design choice by FLI. My ATLAS temp readout lags external temperature by 45-60 minutes.

Every night I start a large fan pointed up and directly under the whole optical assembly, with the OTA pointed straight up (to keep one OTA side from cooling before the other). When I do this at sunset, things are well cooled by twilight (sun @ -9 or -10 deg alt), at which time I remotely stop the fan and ACP does the first FocusMax (thanks, Steve!).