Don't know about anyone else but shutting and securing the observatory door in a closed position requires some elbow grease. I can close and lock it from the outside by pushing in the door but from the inside is a whole different matter. I decided to add a door knob on the inside.
I ordered, from amazon, a T Handle from Pro Line https://smile.amazon.com/gp/product/B000KKX9SU/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 for the parts, there are other sources for these from other manufactures if you're inclined to do the search.
I then took the handles off the of each end of the supplied shaft so I'd have two handles for another use down the road. Anyway, the handles would normally be held on the 5/16" shaft by a pin through the shaft and wedged. Since I didn't want to drill an 1/8" hole through the shaft supplied by NexDome I tapped the two holes in the handle to a #8/32 thread size. I also drilled a small divot in the shaft to anchor the #8/32 set screws, gives it a bit better hold.
When assembled I now have away to grip the door from the inside and close/latch while in the observatory.