Continuously adjustable extension tube with millimetre scale for fine adjustment of the optical length between 15 and 20 mm in the UFC system
The Universal Filter Changer, UFC: The Baader UFC system is a filter drawer that can be used with a wide variety of telescope and camera systems. It has a sufficiently large connection diameter, is extremely short in design and can accommodate filter sizes up to 50x50mm without vignetting. These features are essential for operating the new, fast optics such as EdgeHD telescopes with Hyperstar and the new RASA instruments from Celestron, as well as all other prime focus astrographs with suitable filters, where a regular filter wheel would block too much of the front aperture. In addition, prime focus optics are inevitably equipped with a very short back focus and require a particularly space-saving filter drawer.
The UFC system can connect almost anything to anything by purchasing the same filter base housing and then simply selecting the necessary front and rear plates of the UFC together with the spacer rings as required by the respective chip spacing. For this purpose, Baader offers a set with matching UFC extension tubes and an S70 VariLock extension that is continuously adjustable from 15 mm to 20 mm to keep the distance between the filter and the image plane as short as possible. All components are optimised to achieve the greatest possible passage in front of the actual filter drawer while still allowing the distance between the telescope and the chip to be precisely adjusted. The filter drawer itself is therefore positioned as close as possible to the camera, minimising shadowing by the filters.
