Light is reflected from the barrel directly through the glass element and is then reflected from the mirrored internal surface of the outer objective barrel, before being refracted to form the hollow cone of illumination by a second lens element.
(Light; is reflected; from the barrel directly through the glass element) (Light; is reflected; from the mirrored internal surface of the outer objective barrel; T:before being refracted; T:then)
Light Light
is reflected is reflected
from the barrel directly through the glass element
from the mirrored internal surface of the outer objective barrel T:before being refracted T:then