Takahashi 1.25" 1.6X Extender-Q for Takahashi Refractors

This dual purpose Takahashi optical system is both a 2" 1.6x Barlow and a field flattening photographic tele-extender designed for use with Takahashi FSQ-106/Sky 90 refractors.

The 1.25" Extender-Q is a visual and photographic amplification device designed for use with older Takahashi FSQ-106N and Sky 90 refractors. It changes the FSQ-106N from a 530mm f/5 to an 850mm f/8 and provides a 44mm image circle with a 3° field. The Sky 90 changes from a 500mm f/5.6 to an 800mm f/9. However, tests have shown that the Extender-Q will give you similar 1.6x magnification and focal ratio results with every Takahashi refractor, and not just the fast focal ratio FSQ-106 and Sky 90.

The Extender-Q threads into the Takahashi focuser drawtube before the 1.25" eyepiece adapter and so cannot be used with non-Takahashi scopes.

This extender is not a simple two-lens achromatic Barlow lens, but rather a sophisticated optical amplification device using five lenses in three groups that functions as both a visual Barlow and a photographic tele-extender. Its five-element optical system is fully multicoated for maximum light transmission and contrast. The Extender-Q produces a flat, color free, extremely high contrast image that can be used for high magnification lunar and planetary visual observation or photography and CCD imaging.

An additional advantage of the Extender-Q is that it corrects the image in the ultraviolet portion of the spectrum that is invisible to the eye, but is easily recorded by CCD cameras. Stars that radiate strongly in the ultraviolet appear closer to their naked-eye visual appearance when imaged on a CCD camera through the Extender-Q. They do not have a bloated appearance on photos due to their normally invisible UV component being recorded by the CCD camera and added to the visual image. This feature only adds to the photo/visual capabilities of Takahashi scopes.

The Extender-Q threads into the focuser drawtube, in place of the 1.25" eyepiece adapter (which is unthreaded from the focuser drawtube and reinstalled on the end of the Extender-Q). Several extension tubes in the Extender-Q body add the needed extra light path distance to allow eyepieces and a 1.25" star diagonal to focus. An optional 2" adapter #TEQ0002, shown below, threads into the end of the Extender-Q in place of the 1.25" adapter to let you use a 2" star diagonal and 2" eyepieces with the Extender-Q.

The maximum length of the Extender-Q (5.5") is only used for photography and straight-through visual observing. With a star diagonal, two of the extender tubes in the Extender-Q body are removed, shortening the Extender-Q length to 3". Rubber grip rings on each section make it easy to assemble and disassemble the unit.

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