Baader D-ERF Energy Rejection Filters for H-alpha Solar Observation Size:160mm Supports manual focus control via

Supports manual focus control via handle controller and includes a temperature sensor for increased precision

operated by 2XAAA batteries (not included)

Photosphere filter is an assistant filter

allowing easy integration with dovetail bars

High Speed – Rotates up to 7

Baader D-ERF Energy Rejection Filters for H-alpha Solar Observation Size:160mm Supports manual focus control viaBaader Energy Rejection Filter (D ERF) H Alpha Solar Observation Filter The Baader Energy Rejection Filter (D ERF) is specifically designed for H alpha solar observation, allowing telescopes to achieve full aperture resolving power. This filter significantly reduces the thermal energy entering the telescope, protecting your solar spectrum filter and minimizing thermally induced seeing effects for a more stable and detailed observation experience.