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MPCC Multi-Purpose Coma Corrector, MkIII NEW MkIII Version!


RCC-I, Rowe Coma Corrector  NEW!


RCC Off-Axis Guider  NEW!


Alan Gee Telecompressor Mark II


Turbo Film

MPCC Mark III Multi-Purpose Coma Corrector




(ready to attach to any DSLR or CCD Camera)


MPCC Coupled to 2" eyepiece


MPCC Mk III (Exploded View)

MPCC Configured for 1¼" Eyepieces

The new Baader Planetarium MPCC MkIII enables owners of fast Newtonian telescopes to use their instrument for taking stunning wide-field images, or visually, for delivering wide-field views with stars that remain pinpoint to the edge - with no magnification increase!

The MPCC has been optimized for Newtonians with focal ratios from f/3.5 to f/6, and will deliver 12micron stars across a full 35mm frame size.  Independent optical laboratory tests (by ITE) have confirmed that the MPCC is the sharpest wide-field coma corrector available for imaging, and provides the best edge of field illumination (least vignetting).  Visual users have reported great results even down to f/3.5.  The optics are anti-reflection coated with Baader's PHantom Group Multicoatings.  The MPCC is also priced very reasonably.  It's modularity lets you purchase only the parts you need.  For imaging with DSLRs, only the MPCC is required (for the maximum field size, the MPCC MkIII is designed to work perfectly with the Baader Protective EOS T-rings).  For visual, the MPCC MkIII can be configured with any of our eyepiece holders or directly coupled to 2" eyepieces using Astro T-2 System components.

New Features of the MkIII Version:

  • New Optical Design - calculated for an unvignetted field down to f/3.5.

  • Improved sharpness across the field.

  • Phantom Group© Multicoated for maximum transmission and freedom from reflections from UV to NIR.

  • Attaches directly to the Baader Protective EOS T-ring through use of the optional adapter.

  • 44mm Clear Aperture when using the M48 (2") filter thread or the Protective T-ring.


Dob users with f/3.5 - f/5 scopes have been discovering the unique benefits of the MPCC versus other coma correctors.  The MPCC can be inexpensively configured for visual use with 1¼" and 2" eyepieces.  Please see our MPCC Visual Configuration page for new information on some exciting visual configurations. 

  • No Magnification Increase:  The MPCC delivers full fields for the widest 2" eyepieces.  Why spend the big $$ on a large widefield eyepiece, only to have its field squeezed by the coma corrector.  Now, a 31mm ultra-widefield eyepiece can perform like a 31mm, and not a 26mm..  Also, unlike some correctors, the MPCC has minimal effect on the eyepoint and blackout behavior of long focal length eyepieces.

  • No additional Back-Focus (in-travel) Required:  In fact, in direct-coupled configurations, the MPCC actually increases back-focus by about 10mm.  If your eyepiece will focus without a coma corrector, it Will reach focus with the MPCC.  This is not the case with some other coma correctors.

  • Reduced Vignetting:  The new MPCC MkIII now works even better with the largest true field 2" eyepieces.  Due the closer position of the field lens to the focal plane, the MPCC MkIII is able to provide a larger fully illuminated true field than any other coma correctors (both visually and photographically)

  • Low Cost:  The MPCC is priced lower than other correctors.  Some users have even purchased more than one and leave them permanently attached to their favorite 2" eyepieces.


MPCC MkIII - with Baader Protective T-ring

Exploded View

The MPCC is the perfect match for today's Digital SLRs.  Owners of these new cameras find them to be ideally mated with today's fast f/3.5-f/5 Newtonians required to keep exposures short.  The MPCC enables these users to fully correct their scopes and produce superb pinpoint color deep sky images without the complexity of more expensive CCD astrocameras.  Owners of Vixen Newtonians will appreciate the inclusion of filter threads, and the high sharpness of the images.  Unlike other coma-correctors, the MPCC does NOT extend the focal ratio (so, your images will be shot at the full speed of your telescope).

The MPCC inserts into 2" focusers and has external T-threads on the output side (and is also threaded for standard 2"/48mm filters).  Simply attach any 35mm film or digital SLR to the MPCC, using commonly available T-adapters.  Users of CCD cameras can attach in the same way through the use of our Astro T-2 System components (adapters, extension tubes).   The MPCC is designed for a nominal 55mm distance from the mounting flange to the film plane (55mm is the standard dimension for all SLRs, measured from the front of their T-adapter to their image plane). It also extends the focus point by approximately 10mm, so no additional back-focus is needed to use the MPCC (of course, this assumes your camera will already reach focus in your telescope, without the MPCC).

The MPCC alsoincludes a removable stop flange.  Removal of this flange exposes an M48 external thread, which enables the MPCC to be directly coupled to 2" eyepieces and inserted fully inside 2" focusers.   For more info, please see MPCC Visual Configuration.

The MPCC has been tested and found to work well on Meade SN Schmidt-Newtonians (see Bill Christie's comments below)

Please click on the thumbnail below for an example of the imaging improvements from using the MPCC.   These images were sent in by one of our customers using a Celestron 8" f/5 NGT, using a Canon Digital Rebel (300D) at prime focus with and without the MPCC.

"Using the Baader Multi-purpose Coma Corrector from Alpine Astro the coma in my 12-inch f/5 telescope is gone - wow! - my images are now flat across the entire field, and I find that amazing, since this telescope previously produced a moderate to large amount of coma in my images.  The other delightful thing I found was the MPCC screws straight into the bottom of my 2-inch eyepieces.  Thanks Baader, Thanks Alpine Astro."   Paul Mayo, SKY:Lab Astronomy Software 

see Paul's outstanding images taken with the prior version MPCC at

Conclusion: A Baader MPCC Coma Corrector with proper collimation, tracking and good focus WILL give you pinpoint stars in your photos, right across the field of view (1.6 degrees in an SN-8). The Baader MPCC Coma Corrector joins the Telrad and Accufocus in my list of MUST-HAVE equipment (for astrophotography) when using a Meade LXD-75 SN-8. Bill Christie (see this site for some nice comparison shots with/without MPCC)

The weight of the MPCC by itself is 80gm (2.8oz).


- Baader MPCC MkIII, Multi Purpose Coma Corrector (# MPCC)

- MPCC T-Ring Spacer (#MPCC-SPCR) optional, required for max field size with EOS Protective T-ring






RCC I  Rowe Coma Corrector




Baader RCC-I


RCC-I + VariLock 46 + Canon EOS


RCC-I + RCC Guider + Canon EOS

The new Baader Planetarium RCC-I (Rowe Coma Corrector) is designed specifically to correct Coma in fast Newtonian imaging systems.  The RCC is the ideal match for today's Digital SLRs and CCD Cameras. 

  • Long Back Focus: The RCC-I triplet optical design has been optimized to work at a large 91.5mm back-focus distance, enabling the use of Off-Axis Guiders, Adaptive Optics, and Filter Wheels.  The RCC even allows users of DSLRs to incorporate off-axis guiding with the Baader RCC Off-Axis Guider.

  • No magnification increase:  Unlike most other coma correctors, the RCC-I does not impart a barlow effect - it works at 1:1, with no loss in imaging speed or reduction in field size.

  • Fast Imaging Speeds:  The RCC-I has been optimized for Newtonians with focal ratios from f/3.5 to f/6 (nominally designed for f/4).

  • Ease of Focus: Addition of the RCC-I into the optical train extends the focal point slightly (approximately 5mm, in an f/4 system).  This important attribute ensures that your system will be able to reach focus without needing to shift the primary mirror or increase the size of the secondary mirror ( * IMPORTANT; this assumes your system will already reach focus without the RCC).

The RCC-I inserts into 2" focusers and has external T-threads on the camera side for attachment to any other T-threaded accessory.  The RCC-I also includes a removable stop flange.  Removal of this flange allows the RCC to be fully inserted into 2" focusers.  The RCC is also threaded for standard 2"/48mm filters. 

The RCC is designed for a nominal 91.5mm distance from the mounting flange to the image plane (55mm is the standard dimension for all SLRs, measured from the front of their T-adapter to their image plane). The 91.5mm distance needs to be held to within +/-3mm for best image quality.  We sell a range of adapters and extension tubes that can be used to configure practically any imaging system to meet the 91.5mm requirement (see Astro T-2 System).  In particular, we recommend the Baader VariLock Variable Extension Tubes.

Users of DSLRs will find the Baader RCC Off-Axis Guider to be the perfect compliment to the RCC-I.  It is designed to have the proper spacing needed to meet the 91.5mm requirement, and offers precise axial and radial adjustments for ease of locating guidestars.


* Back Focus Example: assume that you have a DSLR and the matching Baader RCC off-axis guider.  That combination of equipment has a combined path length of 91.5mm (which is intentionally the back-focus spec of the RCC).  If you attach a plain 2” nosepiece to the front of the Off Axis Guider + DSLR and then insert them into the 2” focuser of a Newtonian, your scope would need at least 91.5mm of back focus in order to reach focus on the chip of the DSLR.  Now, remove the 2” nosepiece and replace it with the RCC-I.  Re-insert the assembly fully into the focuser until the off axis guider seats against the focuser (the RCC inserts fully into the focuser since it is 2” OD), focus the camera, and you should find that the focuser would be racked out about 5mm farther than it was with just that plain 2” nosepiece.

The weight of the RCC by itself is 142gm (5oz).


- Baader RCC-I, Rowe Coma Corrector (# RCC-I)





RCC Off-Axis Guider





RCC Off-Axis Guider


RCC-I + RCC Guider + Canon EOS

(also shown with LVI SmartGuider)

Baader's new RCC Off-Axis Guider is matched specifically for the RCC-I Coma Corrector and Digital SLR cameras.  The guider's 36.5mm body length sets the backfocus at the 91.5mm nominal distance required for the RCC-I.

The RCC Off-Axis Guider incorporates convenient axial and radial guidestar adjustment, without loosening or affecting the main camera connection or orientation.  For axial (front to back) guidestar alignment, simply turn the small knurled thumbscrew either direction to shift the guidestar along the optical axis (the thumbscrew actuates an internal mechanism that tilts the internal prism).  For radial (side to side) adjustment, loosen the bottom knurled thumbscrew and rotate the body radially (140 degree range). Simple, precise, and robust.  Accepts 1.25" autoguiders and guiding eyepieces. 

The weight of the RCC Gider by itself is 165gm (5.8oz).

- RCC Off-Axis Guider  (# GUIDER)


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Alan Gee Telecompressor Mark II



A common limitation that plagues owners of most popular Schmidt-Cassegrain telescopes is the narrow field size and high magnifications produced by their slow optical system (typically, f/10).  Until now, owners of SCTs have lacked a truly versatile and high-quality method of reducing their f/10 (or slower) systems for faster, wider, photographic/CCD and visual fields. (note: the telecompressor is not intended for use with the Meade native f/6.3 SCTs).  Using the Alan Gee with 1¼” eyepieces can yield actual fields of view that match or exceed what you could only achieve with expensive 2" eyepieces!

Baader Planetarium has developed a truly unique and  extremely versatile telecompressor system that delivers the finest wide flat fields your SCT is capable of.  The key to the Alan Gee Mark II Telecompressor is its innovative optical and mechanical design.  Unlike the commonly available and simple single-purpose solutions, the Alan Gee Telecompressor Mark II has been engineered specifically to work well with SCTs in a wide variety of visual and imaging configurations.   The unique design of the Alan Gee Telecompressor positions the lens elements several inches inside the telescope's central baffle tube (see the C8 Cutaway, which shows the lens mounted in the standard imaging configuration).  The result is a sharp, wide, flat field, at a fast focal ratio of f/5.9 – and it even works superbly with Baader Planetarium, Zeiss, and Celestron Binocular Viewers!

That's right.  The Alan Gee Mark II is designed to function with many popular  binocular viewers.  At last, you can use your large aperture SCT to produce stunning wide field binocular views.  For more information on this unique telecompressor system, including some sample CCD images, please click on the link below.











Baader TurboFilm is the highly transparent crystal clear film (not Mylar!) developed for scientific applications and used as the base material for the renowned Baader AstroSolar. It is a monomer film which was found after thoroughly testing more than 200 different film samples on Baader's Zeiss autocollimator. This film was used in German Science Institutes as an optical membrane for nuclear and particle physics experiments. The basic substrate has been further refined and homogenized by a proprietary annealing process that was developed exclusively for Baader Planetarium. Due to these treatments Turbo Film attains near-perfect homogeneity and performs equal to a 1/10 wave plane parallel optical window. In fact it has the lowest wedge error of any existing optical window. TurboFilm will protect your valuable optical equipment, close telescope tubes against dust and humidity, greatly reduce air currents - all without reducing the optical quality of your telescope.  This amazing optical material enables cost-effective uses for amateurs and professionals that were never before possible.


Some Suggested Uses:

  • Precision Optical window for Newtonians and Cassegrains (ie, Tak Mewlons) up to 20" Dia. (or off-axis windows for larger telescopes).   Reduce Tube Currents, Seal out Dust and Dew to Protect Coatings.

  • Optical window for protecting all telescopes (incl. refractors) from harsh conditions (ie, salt spray near coastal areas).

  • Sealing of Observatory Dome Slits or Observing Room Windows.

  • Industrial and Research Uses: Cost-effective precision optical windows for sealing of test chambers and enabling remote optical inspection.  Isolation of large fluid optics.


  • Roll Size: 127 x 51cm (50" x 20")

  • Thickness, 12micron (0.0005")

  • Transmission @633nm ~95%.

Note: In order to maintain the high optical quality of TurboFilm, the film must be mounted free of stress and wrinkles.

To create a precision optical window for your telescope using TurboFilm, click on the following link for a method of constructing a simple and inexpensive cell.

For an interferometric report on the optical performance of TurboFilm, click on the picture link below:

TurboFilm Interferometric Report





Last Update 03/14/11


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