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Baader Planetarium Flip Mirror II Off-Axis Guider

SKU: BAD-BFM-OAG
$144.00

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Baader Flip Mirror II Off-Axis Guider

  • This Baader Off-Axis Guider attaches directly to the Baader Flip Mirror II Star Diagonal.
  • No other prism is capable of being tuned to actively center a star on the guiding chip.
  • With this OAG, an autoguider camera that is adaptable to each mirror position can be added to the Baader Flip Mirror II.
  • Nearly any camera can be placed above the BFM-OAG by using one or two DT-4 nosepiece extensions for parfocalization with the recording camera.
  • Back focus requirement on the BFM II is 24 mm.

Designed to fit the 19 mm nosepiece port on the bottom of the Baader FlipMirror II, this Baader Off-Axis Guider is able to transfer light to an autoguider via a pickup-prism, regardless of mirror position. A separately available RCC Off-Axis Guider with T-2 threads is needed in order to attach the BFM OAG directly to telescope without the BFM II.

The BFM OAG comes with a small spacer ring which can be removed for direct attachment to the Baader Flip Mirror II. This allows the prism to be fully inserted into the BFM II's light path.

Please note: this is the only prism that can be tuned to actively center a star on the guiding chip. The vertical side of the prism must face the telescope.

When the mirror is down to, for example, guide a planetary camera connected to the upper port, the prism must always be below the mirror for use. With the mirror up, rear port camera alignment needs to be aligned so that the prism is below the long side of the sensor.

Several options exist for setting the guide camera to the same focus plane as any camera or eyepiece connected to the main light path of the FlipMirror II. The position of the camera/eyepiece can be altered via the typical combinations of T-2 and M48 extension tubes. For additional distance between the autoguider and the BFM II, you can include one or two optional DT-4 nosepiece extensions, and fix the position using an optional FR-4 Focusing Ring Collar.

Those using an Off-Axis Guider must also consider the focus position of the guiding camera. If you use the Off-Axis Guider for Baader Flip Mirror II as well as a guiding camera whose image plane is at the upper end of the OAG (i.e. without additional back focus), the image plane of the camera and eyepiece is about 24 mm behind the two BFM II T-2 threads. A CCD camera with a short back focus, for instance, can be adjusted to this distance with a VariLock 29, as can the Polaris I crosshair eyepiece when connected directly to the VariLock 29 via T-2. Thus, a very short adaptation is possible.

Using a DSLR via a T-2 adapter, or an eyepiece clamp for the eyepiece, requires more back focus. Then, the guiding camera must be placed at a greater distance from the BFM II. The easiest way to do this is to use a DT-4 nosepiece extension which has an overall length measuring 18.5 mm with a 1.25" diameter that can be screwed into the 1.25" filter thread of the guiding camera. With one or two of these extensions, virtually any camera can be placed over the off-axis guide so that it is parfocal with the recording camera.