Well, these are the best pictures I have from this thread old thread.

Portable_Exploradome

There is another option, and that is to make an observatory out of or on a trailer. I've seen a couple of these home made setups but the issue there is to get an isolated pier.

There is also some company that makes actual observing trailers, professionally built, but the price tag is like $20K.

I think the real issue with an observatory on a trailer or as a trailer is that you're limited to observing from where you can actually drive the trailer. Often this no further than a lighted parking lot where the rest of the campers have to stay. The Exploradome that detached from the trailer was a big advantage since I could "drop it off" and get the truck and trailer out of there.

I always wanted a portable observatory for star parties and dark sites. The portable Exploradome was really oool, probably the ultimate rig. If I had a larger truck and yard space to store it, I probably would still be using it. For my uses, the Astrogazer ended up being more practical.

The pros and cons of the two:

Exploradome pros:
Solid design
Ease of setup
Lockable

Exploradome cons:
Trailering and storing
Smaller size
Setup limited to where the trailer can be driven
Cost

Astrogazer pros:
Much larger interior
Easier to transport
Easier to store
Much less expensive

Astrogazer cons:
Not lockable
Must be set up
Not as weatherproof