The author's telescope is aimed into a
siderostat mirror for shooting the eclipse, which explains its unusual pointing angle.
The mirroring device, called a single-mirror siderostat, had been invented in 1862 by the French physicist Leon Foucault.
In the final design, the telescope's key moving element was a flat, 2-meter silvered glass mirror 27 centimeters thick in a fork-mounted siderostat. It directed light into the 1.25-meter, f/48 objective and down a fixed tube.
The outgrowth of numerous discussions with other eclipse photographers, especially my colleague Roger Sinnott, and past experiences, it's a variant of a polar telescope fed by a siderostat. Since the scope's optical axis lies on an imaginary extension of the siderostat's polar axis, the mount has to be made for the latitude of the observing site.
I fashioned the siderostat around a polar drive scavenged from a broken German equatorial mount made by Carson Telescopes.
The individual "
siderostat" telescopes will be movable to keep the light path stable to about 10 angstroms.
This pair of early A dwarfs, first noted at Narrabri (Hanbury Brown et al 1974) has now been resolved using the VINCI instrument and two of the VLTI
siderostats (Kellerer 2008).