Filter Drawer System
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. 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 22mm and due to that fact, can be used also at scopes with a high focal ratio.
The main body o f the filter drawer has a male and a female thread. Various threads are available.
Versions with holes for SBIG cameras is also available. If you use a mainbody with a female M48 thread on the telescope side, you can use your older lenses from Olympus and Nikon with your CCD camera with the filter drawer system.
Appropriate adapters to 2" and other fittings are also existing.
I recommend three or rather four filter drawers, either for 2" or 1.25" filters, for the standard equipment.
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telescope side
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focus side
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female T-thread (M42x0,75)
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male T-thread (M42x0,75)
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M42x1 female thread
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M42x1 male thread
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M48x0,75 female thread
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Holes for SBIG cameras
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Mister R. Hilz, M ering 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.
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).
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