Refractors still require a cool down, although they do not require as much time. The air space will usually cool down quicker than a mirror. Bino's probably don't require much time at all.
my 10" reflector needs at least 1/2 hr to 1hr after the outside temp stablizies to get within 1 degree. Now the putside temp does not always stablize, so it gets fiddly when imaging down here in tassie
i am using ice packs to speed this up and making a mini "Bird" peltier cooler.
