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Astrodon - Monster MOAG Off-Axis Guider 3" Male for CFW

Model#: MMOAG-3-LL

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Availability: In stock


Manufactured by: Astrodon


MonsterMOAG Off-Axis Guider

MOAG means Manual Off-AxisGuider, a non-moving part of your optical train. 

The MonsterMOAG™ is the intermediate member of our off-axis guider product line.  It is specifically designed to accommodate the larger CCD detectors (36 x 36 mm), such as the Kodak KAF16803E and KAF9000E.  Furthermore, at 1.25", it has thinnest backfocus for an OAG available, making MonsterMOAG™ an ideal choice for systems with minimal backfocus, such as the Takahashi FSQ refractor (see side bar link to MonsterMOAG installation on an FSQ106N). 

There is only one MonsterMOAG that has been tested on telescopes/ CCD camera systems under full weight load.   OurMonsterMOAG comes with Astrodon quality and support  and a wide array  of Astrodon-designed adaptors.


  • For largest CCDs (KAF16803, KAF9000)
  • Smallest backfocus 1.25"
  • Large central opening of 2.55"
  • Guide in front of your filters
  • More guide stars with unfiltered light
  • Guide in the main optical beam
  • Avoid differential flexture and cost of guide scope
  • Fixed guider position for automated data acquisition


  • Solid body for no flexure
  • Helical focuser for easy focusing of guide camera
  • Short, manual 1.25" camera holder also included 
  • Additional prism spacers included
  • These provide maximum flexibility to come to focus
  • M/F AP 2.7"-24TPI dovetail adaptors included
  • Female 2.7" also has 3" Male for CFWs
  • Dovetail connectors to align with camera / telescope
  • Low reflectivity inner surfaces
  • Wide variety of adaptors
  • Optional f/-250 lens to extend focus ~ 12 mm


The included camera-side adaptor has 3"-24 external male threads that will connect directly to earlier Apogee, current FLI and SBIG STX CFWs that have 3" openings.  The latest Apogee CFW (AI-FW50-7S or -9R) will require the optional MMOAG-CFW-A adaptor shown below right due to an interference.  It has 0.2" of backfocus compared to 0.1" for the included adaptor.

The optional MMOAG-STL adaptors have 2.156"-24 threads for STL cameras and you can choose the amount of separation (added backfocus) you want between the MonsterMOAG and the CFW/CCD.  The optional MMOAG-ST adaptors have 42 mm t-threads for SBIG ST and similar CFW/CCDs. 

The included adaptor also has internal female 2.7"-24 threads. You can add the Astro-Physics ADA2003 part that has male 2.7" threads and accepts 2" nosepieces from the camera. This part ads 3/4" of backfocus.  Furthermore, you can use the Astro-Physics ADA204 male/male 2.7"/2.0" adaptor.  This would have 2"-24" males threads toward your CFW.  Some FLI CFWs have 2" female threads.  The ADA204 adds 1/4" of backfocus.

Lastlly we offer a male/male 3"/2.7" adaptor (CFW/APM) that can also screw into the larger filter wheels.  You can then add a variety of Astro-Physics or RC Optical Systems 2.7" extension tubes, since they will screw directly into the included camera-side adaptor on the MonsterMOAG.


The MonsterMOAG comes  equipped with a dovetail to 2.7"-24 males threads.  This works for most RC scopes (e.g., RCOS) with 2.7" extension tubes and adaptors that go from 2.7" to larger (3.5" and 4") systems. 

For Takahashi FSQ and TOA owners, you can add the CAA-APF adaptor along with Spacer27.  This converts the back of the camera angle rotator from metric to 2.7"-24 female threads. The MonsterMOAG then screws into the CAA-APF.

For those with Meade or Celestron SCTs with 3.25" visual backs, you can purchase a 3.25" female to 2.7" female adaptor from Astro-Physics for $60 (Celestron  - ADASCTLC27; Meade - ADASTLM27).  This screws onto the visual back of your SCT and accepts the 2.7" male threads from the MonsterMOAG.  In this way you can enjoy the benefits of off-axis guiding in the main beam without worrying about differential flexurre with guidescopes or possible primary mirror movement as the scope tracks across the sky.

Product Series

MOAG means Manual Off-Axis Guider, a non-moving part of your optical train.


This smaller member of our off-axis guider product line is specifically designed to be integrated with SBIG adaptive optics (AO) devices, including the ST/AO8 and STL/AO-L systems. AO technology allows fast guiding that can dramatically lead to sharper stars and finer detail. The MOAG can also be used as a stand-alone guider for any camera. For stand-alone applications involving KAI11000XM and larger detectors, we recommended the MonsterMOAG or MegaMOAG.


  • Take full advantage of AO technology
  • Faster AO guiding for better resolution
  • Guide in front of your filters
  • More guide stars with unfiltered light
  • Guide in the main optical beam
  • Avoid differential flexture and cost of guide scope
  • Fixed guider position for automated data acquisition



  • MOAG-ST for SBIG ST/AO8 with T-thread adaptor
  • MOAG-A for SBIG STL/AOL with 2" STL adaptor
  • MOAG-S stand-alone with AP 2.7"-24 M/F adaptors
  • Dovetail adaptors to rotate and align MOAG
  • 2 3/8" backfocus for ST/AO8 or STL/AO-L
  • Helical focuser for easy focusing of guide camera
  • Removeable (barlow) lens to extend focus
  • Solid construction - no flexture
  • Optional eyepiece extension
  • Optional short 1.25" nosepiece holder





Additional Information

Name Astrodon - Monster MOAG Off-Axis Guider 3" Male for CFW
Manufacturer Astrodon
Model MMOAG-3-LL