- -7%
Daystar Filters Energy Rejection Filters ERF 80/120 mm
489.00CHF
454.77CHF Save 7%
Tax included 
Usually available from the supplier. Please contact us for more information.
Available payment methods
i
PayPal
Secure payment. Additional fees may apply.
PayPal
i
Bank transfer
Pay comfortably from home. After confirming your order, you will receive all the information required to make a bank transfer.
Bank transfer
i
Pay in store
Pay directly in our shop in Givisiez, in cash or by card. Your order can be collected after confirmation.
Pay in store
i
PimPay
A payment system with no fees. Simply top up your PimPay account before completing your purchase. No fees are charged to either the buyer or the merchant.
PimPay
i
HeyLight
Credit for up to 12 months or payment in 3 instalments. For payment in 3 instalments, the displayed price includes a 3.74% surcharge applied by Astromanie to cover the service fees associated with this payment method.
HeyLight
Daystar Filters Energy Rejection Filters 80/120 mm
Daystar Energy Rejection Filters reduce thermal load by blocking UV and IR while transmitting visible light. The 80/120 mm model fits refractor tubes up to 120 mm in outside diameter and optimizes Daystar solar filter performance.
Daystar Filters Energy Rejection Filters 80/120 mm
Description
Daystar Energy Rejection Filters (ERF) are designed to significantly reduce the amount of heat entering the optical system during solar observation. They absorb or reflect ultraviolet and infrared radiation while allowing only the useful visible spectrum to pass. Depending on the model, the ERF may be manufactured from red or yellow glass, or from dielectric-coated glass engineered to block IR and UV efficiently.
The ERF also functions as an aperture mask, ensuring a proper angle of incidence for incoming light. Since Daystar filter assemblies perform best at f/30 or slower, the ERF helps achieve this focal ratio by reducing the effective aperture or by working in combination with a suitable Barlow lens.
To determine the proper reduction aperture, the telescope focal length must be divided by 30. When using a Barlow, the multiplied focal length must be used in the calculation. The 80/120 mm model includes an 80 mm ERF glass mounted in a cell designed to fit refractor tubes with an external diameter of up to 120 mm.
It provides effective thermal reduction, improved optical stability, and safe long-duration solar observing. Compatible with many refractors, it is an essential component for stable and high-performance narrowband solar observation using Daystar systems.
Technical specifications
UV/IR thermal load reduction
Visible-spectrum transmission
Red, yellow, or dielectric-coated optical glass (depending on model)
Aperture mask functionality
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 120 mm OD
Suitable for many refractors
Optimized for Daystar systems
Enhanced thermal and optical stability during long solar viewing
Suitable for H-alpha observation depending on filter used
ERF DS Filters 80/120 (E-120N80)
Daystar Filters Energy Rejection Filters 80/120 mm
Daystar Energy Rejection Filters reduce thermal load by blocking UV and IR while transmitting visible light. The 80/120 mm model fits refractor tubes up to 120 mm in outside diameter and optimizes Daystar solar filter performance.