: I am a technical professional living in rural Manitoba & am getting into astronomy. : Winter temperatures here run to -30dC or colder with day/night variations of as much as 20dC.

: I'd like to build my observatory with a glass window (rather than opening the obs to the night air) and heat the interior. : I have heard you can't stargaze through a window but I haven't heard a good solid scientific reason why not. : I assume there will be distortions due to the thermal activity at the glass, but various methods could be used to minimize : the distortions.

: Does anyone have first-hand experience with "viewing thru glass"?

***I seem to remember many years ago an article in S&T,about observing throw a optically flat plate glass window but such glass mounted over head would most likely bend distorting your image and it would not be hail proof, tempered glass is stronger but contains iron that can reduce light transmission to 80-85% and would not be optically pure throw its thickness, finally heat transmission throw the glass would cause thermals on the outside surface that would be magnified by the telescope as well as condensation, take Steves advice and dress warmly and observe outside and shiver like the rest of us...Bob. : Thanks for the input!!