Daystar Filters Energy Rejection Filters 80/110 mm

Daystar Filters Energy Rejection Filters 80/110 mm

Description

Daystar Energy Rejection Filters (ERF) are engineered to significantly reduce heat entering the optical system during solar observation. They absorb or reflect ultraviolet and infrared radiation while allowing the useful visible spectrum to pass. Depending on the model, the ERF may be made from red or yellow glass or from dielectric-coated glass designed to block IR and UV.

The ERF also functions as an aperture mask, ensuring a straight angle of incidence for incoming light. Since Daystar filter systems perform best at f/30 or slower, the ERF helps achieve this focal ratio either by reducing the telescope's clear aperture or through the use of an appropriate Barlow lens.

To determine the correct reduction mask, the telescope focal length must be divided by 30. When using a Barlow, the calculation must use the multiplied focal length.

The 80/110 mm version includes an 80 mm ERF glass mounted in a cell designed to fit refractor tubes with an external diameter up to 110 mm. It provides dependable thermal reduction, improved optical stability, and safe long-duration solar observing performance.

Technical Specifications

• Thermal load reduction via UV/IR absorption or reflection

• Visible-light transmission only

• Red, yellow, or dielectric-coated optical glass (depending on model)

• Aperture mask function

• Recommended focal ratio: f/30 or slower

• Compatible with Barlow lenses

• Reduction calculation: focal length ÷ 30

• ERF glass diameter: 80 mm

• Mounting cell compatible with tubes up to 110 mm OD

• Ideal for refractors

• Optimized for Daystar solar systems

• Enhanced stability during long solar sessions

• Suitable for H-alpha configurations using Daystar filters