Guide Your Telescope in Front of Your Filters
Astrodon Off-Axis Guider MonsterMOAG (Manual Off-Axis Guider) allows you to guide your telescope to obtain sharp, round stars by guiding in front of your filters using unfiltered light in the same optical beam as your imaging camera.
Astrodon has been purchased by Optical Structures Incorporated (OSI). The web store has transitioned to the OSI store at FarpointAstro.com.
Astrodon Off-Axis Guider
Astrodon Off-Axis Guider MonsterMOAG (Manual Off-Axis Guider) allows you to guide your telescope to obtain sharp, round stars by guiding in front of your filters using unfiltered light in the same optical beam as your imaging camera. This is particularly important for practical use of narrowband filters. It also eliminates potential differential flexure if you guide with a separate guide scope. With modern, automated data acquisition programs, framing your imaging target and placing a guide star in the guide camera is simple and no longer an issue, particularly if you have a remotely-controlled camera rotator.
MonsterMOAG™ (MMOAG) is specifically designed to accommodate the larger CCD imaging detectors (36 x 36 mm), such as the KAF16803E and KAF9000E. Furthermore, at 1.23″ thick, it has one of the thinnest backfocus for an OAG available, making MonsterMOAG™ an ideal choice for systems with minimal backfocus, such as the Takahashi FSQ106N refractor. However, it is strong enough to handle heavy loads from larger cameras and filter wheels.
When installed, the MonsterMOAG becomes a fixed part of your optical train along with your camera and filter wheel. When you rotate your camera at the back of your telescope, these three components will rotate together. This means that the guide camera location will be fixed relative to the imaging camera. You define this once as your Field-Of-View-Indicator (FOVI) in programs like Software Bisque’s TheSkyX. Then you can frame your target while ensuring that the guide camera has a star to guide on.
The new MMOAG-1,2,3,4 introduces the capability of attaching up to 4 guide ports to the MonsterMOAG. This was accomplished by making the body square and adding a hole on each side for insertion of the pick-off prism from the guide port assembly. Thus, one possibility could include one guide camera and one 1.25″ eyepiece, for example. Any unused guide port will be shipped with a removable black metal plate. Extra guide port assemblies can be ordered at a later date. The thickness (backfocus) and adapters are the same as before.
- For largest CCDs (KAF16803, KAF9000)
- Small backfocus 1.23″ of the body
- Total backfocus with both provided adapters is 1.45″
- Solid body to hold large camera, filter wheel, filters
- Large central opening of 2.55″
- Guide in front of your filters
- More and brighter guide stars with unfiltered light
- Guide in the main optical beam
- Avoid differential flexure of guide scope
- Fixed guider position for automated data acquisition
- Helical focuser for precision focusing of guide camera
- Shorter 1.25″ manual holder for guide camera also provided if the helical focuser is too tall to reach focus
- Male 2.7″-24 scope-side adapter (0.1″ thick) included
- Female 2.7″-24 / Male 3″-24 camera-side adapter (0.1″ thick) included
- Adapters have dovetail connections to prevent tilt
- Adapters can be rotated and locked to align with telescope and camera
- Wide variety of adapters and different backfocus
- Additional guide port assemblies come with prism, prism spacers, oval holder, helical focuser and 1.25″ manual holder
MegaMOAG 3″ to 4″ Off-Axis Guider
The MegaMOAG takes the design of the MonsterMOAG and adapts it for telescope systems with larger optical openings. It comes with the same camera-side
adapter as the MonsterMOAG but it has a 4″ opening on the scope side and comes with a 4 1/16″ – 24 male adapter to connect to larger extension tubes found on the back of many larger telescopes. The body is larger and the pick-off prism is further from center. It has the same 1.25″ body thickness as the MonsterMOAG. It comes with either a single guide port (MeMOAG-1) or two ports (MegaMOAG-2), as shown in the picture. As with the MonstermOAG, a black metal plate will cover the unused port for a MeMOAG-1. A second port assembly can be added at a later time with the MonsterMOAG Extra Port Assembly (MMOAG-PORT).