Peterson Engineering - EyeOpener™ 2 inch Visual Back

For Meade LX-400, LX200-ACF, LX200GPS, LX-90 & LX200 Classic

An EyeOpener enhances the performance of long focal length 2” eyepieces
on Meade 10”, 12” and 14” Schmidt-Cassegrain and Advanced Coma-Free
telescopes by increasing the eyepiece optical path size as much as
65%.  Get all of the eyepiece aperture that you paid for while
enjoying the full benefit of 2” eyepieces.

As Schmidt-Cassegrain Telescopes (SCTs) evolved from 8-inch models to
larger-aperture scopes, and as eyepieces evolved from 1¼” to 2”, the
”Schmidt-thread” couplings used for securing 1¼- inch diagonals and
eyepieces to telescope backplates remained unchanged. This ”Schmidt
visual back” supplied with your LX400 or LX200 scope has an internal
diameter of 1½”, and it functions as a 1½ inch-diameter field stop. 
This field stop effectively limits the performance of your costly 2”
optics to the equivalent of 1½” optics.  When using the 1½” visual
back with Meade’s 2” 56mm Plossel (an eyepiece with a full 2” of glass
in the nose)  you loose 65% of the light to your eye! 

Do you think that the large diameter front lens (the ”field lens”) on
your long focal length 2” eyepiece is there for decorative purposes” 
That’s about what happens when you restrict the size of the optical
path to that lens with a 1½ inch-diameter field stop.  Without the
EyeOpener® you’re getting the equivalent of 1½” optics.  You might as
well take a piece of 1/4” wide masking tape and cover up the outside
1/4” of glass on the nose of your eyepiece.

How does it mount”  The EyeOpener threads onto a 3-1/4” male thread
found on the backplate of 10”, 12” and 14” Meade SCT & RC scopes,
providing a full 2”  unrestricted optical path.  The microfocuser
attaches directly to the EyeOpener.  Unscrew your 1-1/2”visual back
and check it out for yourself.  To use the EyeOpener on  LX400 scopes
and on the older ”Classic” Meade SCTs, or to shorten the optical path
by eliminating the Microfocuser you will need the EyeOpener 2” Tube
Adapter.  The EyeOpener will also allow ”Classic” SCT owners to
retrofit a Meade #1209 Zero Image-Shift Microfocuser or JMI’s NGF-S
electric focuser.

Microfocuser mounting thumbscrews now included.  Do you recall the old
proverb about the added straw that broke the camel’s back”  Meade’s
LX400 and LX200 scopes are heavy enough to transport without the added
1-1/4 pound weight of the Microfocuser.  Replace the 3 mounting set
screws in your Microfocuser with these special thumbscrews, and your
Microfocuser is readily detachable for scope transport or storage.  A
plug-type dust seal is also included with the EyeOpener. 

Note that the EyeOpener will not improve your viewing with 1-1/4”
eyepieces or with the smaller 2” eyepieces.  But it is hugely
beneficial when used with the larger 2” eyepieces that give you your
widest actual field of view.