3
Figure 3.
Mechanical features of High-
Power Barlow Lenses (shown for a 1.25
"
Barlow)
Figure 4.
The end of the barrel has
female threads that allow use of Orion
1.25
"
(shown) or 2
"
filters (depending on
the barlow size)
1.25"
barrel
Brass compression ring
Filter
threads
Thumbscrew
Rubber grip
Safety slot
Machined from solid aluminum, High-Power Barlows have a grooved, grip-friendly rubber
exterior on the housing
(Figure 3)
. A brass compression ring secures any inserted
telescope eyepiece in place without marring or scratching the barrel, keeping your
eyepieces like-new. The 2" Barlow has two thumbscrews for securing an eyepiece while
the 1.25" Barlows have one thumbscrew.
High-Power Barlows’ lens elements are fully multilayer coated with anti-reflection
coatings, and edge-blackened to provide maximum light throughput and optimal image
contrast. The 1.25" and 2" barrels (depending on model) are internally blackened and
glare threaded to help prevent internal reflections from reducing image contrast. The
barrels have a recessed safety slot to prevent the Barlow from falling out should the
locking thumbscrew become loose during use. The barrels are threaded at the end for
use with Orion 1.25" or 2" filters, depending on the model
(Figure 4)
.
use of orion High-Power Barlows
For refractors and Schmidt-Cassegrain telescopes, you can insert the Barlow between
the diagonal and the eyepiece or between the focuser (or visual back for SCTs) and
the diagonal. For reflectors, place the Barlow into the eyepiece holder of the focuser
drawtube, then insert an eyepiece into the Barlow lens.
CAUTION!
When inserting a Barlow into the eyepiece holder of a diagonal, be aware that it
could “bottom out” on the diagonal’s mirror or prism before it is fully inserted! Use extreme
caution to avoid marring or cracking the mirror or prism with the barrel of the Barlow. If you
feel the Barlow touch the mirror or prism, carefully back the barlow out a bit before securing it
with the diagonal’s thumbscrew(s).
