Baader Planetarium Solar Diaphragm 13mm - 113mm, stepless adjustable

Absolutely not. This is a mechanical iris diaphragm only. It reduces the amount of visible light but does NOT block harmful invisible radiation (UV and IR). You must use this device in conjunction with a certified, full-aperture solar filter designed to safely view the sun. Failure to do so will result in permanent eye damage and equipment destruction.

Its primary use is to reduce the effective aperture of a telescope, typically a refractor, for white-light solar observing. This helps to sharpen the image and increase contrast by mitigating the effects of atmospheric turbulence (seeing). It allows you to use the "sweet spot" of your telescope's objective lens.

The diaphragm is intended for custom, do-it-yourself installations. It has four M3 threads on a 60mm pitch circle radius, which you can use to bolt it onto a custom-made filter holder, an adapter plate, or another mounting solution that fits your specific telescope.

While it could be mechanically adapted, this diaphragm is primarily designed for refractors. For Schmidt-Cassegrains and other reflecting telescopes, an off-axis aperture mask is typically preferred to avoid exacerbating thermal issues and image degradation caused by the central obstruction.

No. This is a mechanical device for optimizing white-light solar observing (sunspots, granulation). Viewing solar prominences requires a specialized, narrow-bandpass Hydrogen-alpha (H-alpha) filter system, which operates on entirely different principles.

Atmospheric seeing conditions change constantly. A stepless diaphragm allows you to fine-tune the aperture in real-time to find the exact diameter that provides the steadiest view, a capability that fixed-size masks cannot offer. You can adjust from 13mm to 113mm to perfectly match the conditions of the moment.