My initial plan called for a very simple 6'x6' square box with a basic roll-off roof. The idea was to build a barebones shed for imaging only that would simply house a pier/mount/scope and protect them from weather elements. At one point I've put together a quick mockup box out of scrap wood, placed my setup inside and quickly realized that 6'x6' was simply too restricting... so I started sketching out a 8'x10'' box, using my 8'x12' garden TuffShed as the blueprint to get the feel for the space. 8'x10'' seemed much better and I thought I settled on the size and started researching roll-off roof options.
That's when I realized that I didn't really care for the typical roll-off designs. I've tinkered with a few ideas on paper on how to make the roof less bulky, how to hide the unsightly support beams and columns, how to better seal the gaps from rain, dust, etc. Nothing I came up with seemed all that clever. Then I took a step back and thought, since I'm going through the trouble of building a more substantial structure than I initially planed for, what are ALL the issues that I should be addressing: space, weather, protection from wind and stray lights during imaging, future mount/scope upgrade options, automation. In talking this over with my wife, I mentioned a dome and she said - why don't you just do that? And that was that... I did my homework on dome options and settled on an 8' dome from NexDome as the most practical option (more on this later).
I've used Google's SketchUp to build a 3D model of what the final observatory could look like and used this pretty cool software to jot down actual measurements, get the feel for space, etc. As you can see, my original idea was to have a sloping roof with an opening, which eventually got reworked into a flat roof with solar panel slide above (more on that later!)