25.5mm clamp to M28.5x0.6 male thread adapter

This is the new version of a 25mm clamp. The inner diameter has been increased up to 25.5mm to accept 1" filters as well.

• Front side - 25.5mm inner diameter
• Rear side - M28.5x0.6 male thread

Machined from high quality aluminium alloyWhy aluminium?.

This adapter allows using filters in 25mm (or 1 inch) round frame on 1.25 inch telescope accessories/eyepieces.

The filter frame is hold in place by 3 set screw.

If your filter is bare glass without a metal frame, you may consider using improved version of this adapter with a retaining ring to avoid glass damage by the screws.

This clamp also fits Shelyak’s replacement slits for its ALPY600 spectrometers, which are exactly 25mm OD. This allows to incorporate any of Shelyak’s ALPY-compatible slits into some customized spectrometer designs.

Credits. The sample setup photo is made by Ed Astle. It shows a 25mm EO Ha filter converted to 1.25" standard thread, and installed on the nose of the TZ4S.