Astronomik-ilter wheel FR-03

For the maximum comfort throughout CCD- Observations a filter wheel is a major requirement. Making colour images, you do not have to go after every exposure to the telescope. The controlling software changes automatically the filters and exposes every colour channels without your help.

The filter wheel FR-03 is driven by a stepper motor and is guarded by a little micro controller. It can be controlled by a serial interface as well as by two buttons (+1 position & reset) at the box of the micro controller. An interface suitable for SBIG CCD- cameras is also existing.

The filter wheel is completely made of aluminium and brass. All screws are made of stainless steel. All alu- surfaces are black anodised. The design of the case secures maximum protection against scattered light..

The filter wheel is fitted at both sides with a huge thread M48 x 0.75, to prevent vigneting in your system even when you are using very large chips. A turn- and clampable adapter to T2 or M42x1 for the side of the camera is also delivered. You can set the rotation angle of the camera relative to the filter wheel with that adapter. For the telescope side I offer you an adapter to M42x1, T2, 1.25" and 2" nosepiece. Almost every other connection is feasible.

The filter wheel has an optical depth of less than 25 mm and is that flat, that it can be used also very well at scopes with a high focal ratio. The thickness of the both cover plates is strong 4mm. Due to this very massive design, you can use the filter wheel also in front of large and heavy cameras (SBIG, Apogee, FLI) without having problems with bending of the case. On the other hand, a weight of almost 840g results from the design.

The filter wheel supports the following protocols:

• SBIG
• OES
• DFM
• TrueTechnology
• …further protocols are in preparation.

The filter wheel is available in three different types:

• with a filter carrier with 6 positions for 1.25" filters
• with a filter carrier with 4 positions for 2" filters
• with a filter carrier with 6 positions for unframed filters with a 34mm free pass through

The carrier for the unframed 34mm filters offers a big advance: Due to the very big pass through one gets no problems with vigneting at the edge of the field of view or at your guiding chip even when using very large chips (KAF- 3200, Site etc.). At the same time, 6 filter positions in the wheel are possible, so the choice is not so much determined like at the 2" filter carrier which has only four positions. The carrier can be completely equipped with ASTRONOMIK filters if requested.

The change between the different carriers is very easy. It should not be done in the night at the telescope, but at a desk it is ready in a few minutes. To use the filter wheel in a flexible way, you can buy later other carriers.

The pictures on this page show the first prototype. The production of the first series is already running and the development of the software for the micro controller is finished. The first wheels will be delivered in january 2003.

Here you can downlaod a drawing (PDF, 78KB) showing the FR-03 connections and dimensions.