Portable shadowing walls?

I live in a town and have streetlights, a neighbor's garage light, and now a new building's lights to contend with in trying to preserve my night vision when observing from my backyard. To help with this, I'm thinking of building a portable structure I can put up & tear down to keep me shielded in shadows from all sides.

The lights are far enough away that it looks like they max out at about 7 degrees above eye level, and the closest I can see to the horizon is only about 10 degrees anyways. If I DIY this I'll probably construct it out of PVC pipe and tarps.

Is there a proper name for such a structure? Is this a sound idea? If so, are there any commercial offerings?