Daystar off axis ERF energy rejection filter SCT 80 281 mm

Daystar off axis ERF energy rejection filter SCT 80 281 mm

Description

The Daystar Off-Axis Energy Rejection Filter ERF for SCT telescopes is designed to reduce thermal load on solar filter assemblies. It absorbs or reflects unwanted ultraviolet and infrared radiation while allowing visible light in the required visual spectrum to pass through.

These filters may be made from red or yellow glass or use dielectric UV and IR coatings. The ERF can also act as an aperture mask, ensuring a straight angle of incidence for light entering the filter system.

Daystar filter assemblies operate best at f/30 or slower. Achieving an f/30 configuration can be done using the appropriate ERF and or a Barlow lens. To select the correct ERF, the outside diameter of the telescope tube should be measured at the very front of the telescope.

Technical specifications

• Type: solar filter

• Construction type: ERF pre filter

• Configuration: off axis

• Use: SCT telescopes

• Free transmission: 80 mm

• Diameter: 281 mm

• Mount: lens filter