Hmmmm... I feel really bad, my OTA has rust spots on it, in it, on almost every bolt
and screw open to the air on the mount. It's nearly two years old, and yes the mount
can stay out in the yard (covered of course) for anywhere up to 3-4 weeks. The OTA
doesn't usually stay out, but that's because it's been blown over when the wind has
picked up and I've gone and hit the sack. Otherwise it would stay out too. However
everything else is in pretty good condition includding Primary and secondary mirrors.
Personally it doesn't worry me have a lil bit of rust on there, shows it's used or loved.

Edit to include However if it was worth a few thousand it might
be a different story


regards,CS