While these people aren't through-and-through licensed engineers, they know the conditions at the observatories, they know electronics, etc.  I'm not sure the telescope can operate at -30 because of the lubricant problem as described above: it puts a lot of strain on the motors because of the precise movements of the telescope when it is operating at such cold temperatures, even if there isn't any wind load.  We had a cold snap of -28c for three days back about a decade ago, that's when they learned about this problem with the lubes.  They routinely get into single-digit below freezing (F) temperatures in the winter at night and things are fine as long as the wind isn't too high, it changes the shut-down parameters and they have to keep an eye on the wind load (direction and speed of the wind vs the direction and altitude the telescope is pointing).  But when the temp starts pushing -25c, it's pretty much automatic shutdown.  Damage to the motors just can't be risked because it can be a multi-week shutdown if one fails, and winter is the longest nights for observing!