Pick your target right and you can get plenty of data. I manage 3 hrs easily per target (if picked right) and I have major obstacles - trees, house....
You'd be surprised what you can make out of 3 hrs from a dark sky.
Now as to ruining your night vision, just download and use the KnightVision app (turns your screen whatever colour you want, but has presets for deep red etc) and turn the monitor brightness as low as it goes. Cover it with a red rubylith IF you want - I never have and my night vision is fine. In between, just cover the laptop monitor with a pillowcase or towel or whatever.
http://knightware.biz/knightvision/knightvision.htm
No need to over complicate the REALLY simple.