AMP TS Universal 2.5" flattner for f/5 up to f/9 refractors.
Its NEW. Paid $490 AUD you can have for $300.
http://www.apm-telescopes.de/en/opti...lattening-lens.
2" or T2 flattners are to small for big CCD cameras. This new 2.5" flattner has a open aperture of 62mm. It allows you to use big CCD cameras (for example 24x36 mm) at fast f/5 refractors. The distance between flattner and CCD sensor is 91.5mm - so you can use accessories like filter-wheels or off-axis-guider without problems.
This is only a flattner, there is no reduction of the focal-length. You can use the flattner at f/5 up to f/9 refractors.
