Astronomik-Filter Drawer

The filter drawer is a very reasonable alternative to the filter wheel. If high time resolution is not the important thing, the manual change of the filters is enough.

The filter drawer is fully made of aluminium and brass, no plastic parts. All pieces are black anodised. All surfaces in the ray path are additional blackened to avoid any reflection. Only stainless screws made of V2A are used. The filter drawers are also made of aluminium. No unwelcome infrared can reach the chip - how it would be possible with plastic drawers. The drawers with the filter are fixed in the put in position, without fasten a screw. After every change, every filter will be right back at the same position. The drawers are designed in such a large way, that it is possible to use M28.5 as well as M48 filters (1.25" respectively 2"). (I can also deliver drawers for squared 50x50mm filters (2" filter from Edmund, Schott test glasses) if requested.) The filter drawer has an optical depth of 21mm and due to that fact, can be used also at scopes with a high focal ratio.

The main body of the filter drawer has a T-thread at the camera and at the telescope side. A version with a M42x1 thread for cameras from starlight instruments is also available.

In february 2003 there will be a third version, especially for SBIG cameras available. This version has NO thread on the camera side, but four matching holes for the screws which hold the nosepiece of the SBIG cameras. You save abou 6mm (0,16") with this modification, and you will be able to use classic film lenses with your SBIG camera AND the filter drawer.

If requested, the thread at the camera side can be designed as turn- and clampable. A version with M48 thread on the scope side is available by inquiry.

A appropriate adapter to 2" nose pieces is also existing.

I recommend three or rather four filter drawers, either for 2" or 1.25" filters, for the standard equipment.

Mister R. Hilz, Mering writes:

The Change of the drawers is very easy. It is really a big help not to build out the camera and to unscrew the other filters, especially to put it (camera) back exactly, that the position of the image and the focus is still right. [...] In Summary, I would say a very good product. By designing this product one thought things through.

Drawers for squared filters (50mmx50mm Edmund or SCHOTT- "Test glasses") available for an extra charge.

Another sensible accessory is a T2/ E28.5 insert ring to assemble filters in any position in the ray path between two M42- or T2- Spacing rings (f.e. IR cut off filter right in front of the camera).