A binocular image is produced by two short telescope tubes.
When looking at stars straight overhead, gravity wouldn't bend the telescope tube.
It may also produce a ghost image between the flat R surface and rear of the telescope tube.
May also produce a ghost image between the flat R4 and rear of the telescope tube.
The base will go first, then the support arm and telescope tube.
The eyepieces from both the finder and the telescope tube had been removed!
The telescope tube had the very modest dimension of one inch in diameter.
The telescope tube and supporting structure were completed in 1845.
This method is especially used in solar telescopes where a vacuum tight telescope tube would be too heavy.
Halley specified that the telescope tube be rectangular in cross section.