Baader | Solar Projection Screen (BSPS) Photo projection adapter

Secure solar projection on refractors with angled light path

• Simple observation of the Sun in white light — individually or in groups
• Quick and easy assembly of pre-cut cardboard pieces with pre-mounted adhesive strips
• Also suitable for public follow-up during awareness events, optimized for side observation

For use, you will need (not included):

• An astronomical telescope suitable for solar projection, equipped with an angled light path/prism with at least 3 cm of back focus. Recommended for focal ratios of around f/6 or higher.
• A T-2 threaded eyepiece projection adapter, such as the Photo projection adapter.
• A glass/metal eyepiece suitable for solar projection, with an appropriate focal length allowing for the projection of a solar image of at least 6 cm in diameter. The BSPS has been tested with Plössl eyepieces.

A safe method to observe the Sun in small groups

The Baader Solar Projection Screen (BSPS) offers a secure method of solar projection, allowing small groups to observe the Sun together. This screen is ideal for tracking solar activity — sunspots in white light — as well as the progression of solar eclipses.

It consists of a rear projection screen and a T-2 thread allowing connection to common eyepiece projection adapters. The screen was developed and tested with the Baader OPFA adapter. Used with the corresponding Baader Classic Ortho eyepieces on refractors with focal lengths between 250 and 1200 mm, it produces a solar image that fills the entire projection surface of 9 × 9 cm. Sunspots, darkening of the solar limb, and progression of eclipses can thus be observed. The screen can also be used with other T-2 projection adapters than the Baader OPFA; in this case, the necessary distances must be determined by the user.

Unlike traditional open projection screens, there is no risk of someone placing their hand in the light beam or even looking directly into the eyepiece. Rear projection allows for a completely closed system. The screen can be connected to any telescope suitable for solar projection via eyepiece.