Mike, I believe Google Earth has a feature where you could paste a pic of your land and see the different sun/shade positions throughout the year.
Mike not sure how your house lays in regards to your greenhouse location so I will give you a couple of things I wish I did. I wish I connected the greenhouse to my house somehow. I love the close proximity and the sound of running water is like a indoor pond. I would have it so I could close a double slider and open at will and go into the greenhouse. The ability to use the excess heat in the winter to pump into the residence would be awesome. Keep your greenhouse close you will be making alot of trips there. If you are like me and your wife gets pissed cause you spend so much time there you wont have far to walk to sleep in it. Mike Sylvia is dead on about south face long side. Take into account winter angle and trees blocking the morning sun because that is when you will need the light . I personally would sacrifice the perfect angle to connect to my house though. Just some thoughts to make your decision more difficult hehe.
Well in the South that east side of the greenhouse is a really prime area for growing plants so I'm not sure I would give it up to fish tank. However without seeing diagrams and more details of your plans, it's hard to tell. What kind of system? If doing media bed system you probably want to start out with at least equal grow bed volume to fish tank volume since is is really challenging to keep water quality up even with low stocking if you only have a small amount of grow bed compared to fish tank. Fish tank can become a bit stagnant if you are only filtering and aerating a small portion of the water each hour.
LF, Sounds like you are planning to open up the greenhouse for the summer yes? I think you will want to make the sides and ends roll up or removable because trying to just vent a greenhouse through doors vents and windows here in the South is rarely enough during the scorching weather.
Yea, I guess I hadn't really understood the plan of the fish tank being kind on the outside but Being able to contain it in the greenhouse for winter. (I have trouble keeping track of so many different ideas/discussions unless my mind happens to have a picture of it along with the idea.) Sounds good.