Well, as promised, here are my thoughts after comparing the Orion 40mm
 Optilux and the Pentax 40mm eyepiece.  Both are 2" eyepieces.  The Optilux
 is shorter, and a bit stubier.  The Pentax is a bit taller.  The Pentax
 comes with two eyeguards -- One is the familiar Pentax cone that narrows at
 the top, and twists to the desired height.  The other is a shorter wider
 snout eyeguard.  Both Pentax eyeguards are plastic, rather than rubber.  In
 my test, I used the familiar one that narrows at the top.
 
 The Orion Optilux has no eyeguard, which is a shame because it would really
 improve positioning your eye for better viewing.  People often complain
 about eyerelief that is too short.  But in my own use, I've found that
 eyerelief that is too long (over 20mm) can actually be more of a problem
 because it causes blackouts as your eye roans to far to one side, or too
 close to the eyepiece.
 
 Sharpness:  Both eyepieces seemed relatively the same in sharpness.  The
 Pentax was perhaps a hair sharper, but if so, the difference was
 insignificant.
 
 Coma at the edges:  Both suffered some Coma on my Starmaster 11" EL which is
 a relatively fast scope.  But the the Pentax suffered a bit less, in that
 objects had to be closer to the edge before they started having the seagul
 look.
 
 Width of Field:  The Optilux is advertised as 62 degree aparent field,
 whereas the Pentax is 65 degress.  Actually I was surprised that I could see
 about 10" wider field with the Pentax.  Makes me think that perhaps the
 Optilux is closer to 60 degrees.  The Pentax's field is so obviously wider
 that this is one area in which I would say the advantage is substantial.  I
 didn't expect that.
 
 Contrast:  The Pentax appeared a bit contrastier when I looked at the Orion
 Nebula.  It wasn't a huge difference, but it was enough that I noticed it.
 
 Comfort and Ease of Using:  Pentax won by a huge margin here.  The eyeguard
 allows you to position your eye perfectly, for consistent and comfortable
 viewing. With the Pentax, you can pan around the sky and see things
 comfortably with no blackouts or kidney bean effect.  The Orion won't let
 you do that because a slight movement of the eye from one side to the other
 and you have the blackout effect --- I find that very annoying and tiring.
 That's one of the reasons I didn't like the Televue 32mm Plossly when I
 tried it.  The Pentax is so easy to use, that I was able to track a satelite
 across about a 100 degree stretch of the sky, starting at Orion (that's when
 it came into view in the eyepiece) and traveling Southwest.
 
 Price:  Orion Optiluxe costs $139.  The Pentax 40mm cost $249 at Adorama.  I
 decided to keep the Pentax and return the Optilux.
 
 Andre Hassid