Baader Planetarium Spacers for MPCC

This Baader Spacer Set is designed for use with the Baader Multi Purpose Coma Corrector (MPCC). It includes four specific spacer rings, which may be combined in various ways to achieve a perfect fit! Allows the direct connection of the MPCC to many popular 2" eyepieces.

♦ Directly-Coupled Configurations for 2" Eyepieces ♦

Note:  The new MPCC MkIII version adapts to eyepieces identically to the prior version MPCC (photos below show the prior version MPCC).

The ideal  way to use the MPCC for visual use with 2" eyepieces is to directly couple it to the eyepiece, via the eyepiece's 2" (48mm) filter threads.  This allows the MPCC to be accurately positioned, providing the optimum spacing for top performance and taking the guesswork and error out of setting a continuously variable holder.  The rigid coupling also eliminates the possibility of sag or tilt from variable holders, particularly with the largest and heaviest eyepieces.  This configuration also enables the MPCC to work without needing any additional back-focus.  In this configuration, the eyepiece will actually come to focus about 10mm further OUT than it does without the MPCC.   Since most large Dobs are limited in their back-focus, this may be the only way to achieve coma correction with some eyepieces (short of trimming truss poles..).  Dob users will also appreciate the light weight of the MPCC system, which avoids the balance problems of heavier correctors.

Here are examples of direct-coupling the MPCC to some popular wide field 2" eyepieces   

For best performance, the corrector should be positioned approximately 55mm from the rear mounting face of the MPCC housing to the eyepiece's field stop (+/- 3mm for best on-axis sharpness).  In order to attach and properly locate the MPCC, only 1-3 inexpensive adapters are required.  We also offer a convenient spacer set, that will give you the spacers needed to fit the majority of 2" eyepieces.  Please see the Spacer Tube and Adapter section, below, for a listing of available spacers.

Please refer to the table below for the proper spacer combinations to use for some popular 2" Eyepieces. 

MPCC Direct Attach to Popular 2" EyepiecesEyepiece

Recommended Spacers

(in order, from MPCC to eyepiece)

 * Remove 1.25" Barrel from Hyperion 24mm and attach spacers directly to 2" Barrel

♦ Configurations for 1¼" Eyepieces ♦

As shown in the following images, to use the MPCC with 1¼" eyepieces, the only additional parts required are the T2-15 Reducer/Eyepiece Holder and one or two spacer rings.  The result is a compact and lightweight coma-correcting assembly that slips completely within a 2" focuser.  This configuration guarantees focus in all dobsonians, even those with very limited back-focus.  The T2-15 eyepiece holder incorporates a captive bronze compression ring and two large knurled screws, for a rock solid no-mar clamping of even the largest eyepieces.  For short focal length eyepieces where coma-correction is not needed, simply remove the MPCC and the T2-15 goes back to being a high-quality 2"/1¼" reducer (threaded for 2" filters).  Note:  When used in this configuration, the T2-15 provides 37mm of spacing.

Here are examples of 1¼" MPCC configurations    

For best on-axis performance, all coma correctors need to be located at the correct distance from the eyepiece focal plane.  The MPCC system makes accurate location simple, rigid, and consistently reproducible through the use of threaded spacer rings.  In order to attach and properly locate the MPCC, only 2-3 adapters are required. 

Please refer to the table below for the proper spacer combinations to use for many popular 1¼" Eyepieces. 

MPCC 1¼" ConfigurationEyepiece

Recommended Spacer and Adapter

(in order, from MPCC to eyepiece)

 * Eyepieces with Field Stop location 6mm (0.25") ahead of 1¼" Barrel Stop (towards telescope)

** Eyepieces with Field Stop Location at 1¼" Barrel Stop

***Eyepieces with Field Stop Location 4-6mm past 1¼" Barrel Stop (towards eye)

♦ Spacer Tubes and Adapters for MPCC ♦