Right now your day is almost 12 hours long (we just passed the equinox).
So bringing them in to a 12 hour cycle is fine....you can lengthen it 5
to 10 minutes a day if you choose, but most tropical orchids are
naturally adjusted to 12 hours.

As to temperature...Bring them in in the afternoon when it is in the 70
degree range into your house, and the difference should be less than you
expect.

Remember to repot anything that needs it and that there are critters in
the media from your summer outside. Check for scale and other pests as
you bring them in.

Cheers

Doug



In article ,
wrote:

Electrician is finishing up installing a new metal halide light in
anticipation of bringing my orchids in from outdoors. Then it dawned on
me -- the orchids (catt, phal, vanda & dends) have been summered outdoors
here in western PA so have been experiencing shorter days, longer nights and
cooler temps.
Do I need to bring them back into the bright light and warmer temps
gradually? Your input will be most appreciated. Thanks