AP 130GT first light, star test question

In the fleeting few minutes of my first light with my new AP 130 GT (new from AP), before the clouds closed up, I observed an out of focus star that appeared slightly but obviously flattened on the bottom (inside focus). I had taken the scope out of the house just five minutes earlier, and I'd say the difference between inside and outside temperature was no more than 5 degrees - whatever it was, I couldn't really feel a temperature difference. The scope spent the day in its case in a room that was also at more or less ambient outdoor temperature. The diffraction pattern I observed looked like a textbook picture of the effects of tube currents. But a refractor with such a small temperature differential would show this? Unfortunately, the sky immediately clouded over and the mosquitoes were out in force. At one point during the star test I think one walked across the objective. [gasp]
I gotta say, it would be hard to overstate the beauty of this instrument. This is my first refractor and probably my last.

Dan

>>The diffraction pattern I observed looked like a textbook picture of the effects of tube currents. But a refractor with such a small temperature differential would show this?>>

It does not take a lot of temperature difference to produce tube currents. If in doubt, and you want to rule out any objective problem, and you don't have time to wait for the scope to settle down, look at a star straight up. Tube currents will be at a minimum at the zenith.