DayStar Filters Energy Rejection Filter E-180N130

Energy Rejection Filters

Energy Rejection Filters are designed to reduce the heat load on your filter assembly by either absorbing or reflecting UV and/or IR light while transmitting light within the desired visual spectrum. These filters typically come in Red or Yellow glass variants, or as dielectric IR and UV filters, ensuring that light in the desired visual spectrum is passed through. Additionally, the ERF can serve as an aperture mask to ensure a straight angle of light incidence when entering the filter.

DayStar filter assemblies are optimized for operation at f/30 and slower. Achieving an f/30 configuration is easily accomplished with the appropriate ERF and/or barlow, as outlined below. If your telescope model is not listed, please refer to our full list of reflectors or refractors, or reach out to us for assistance. Higher resolution and larger aperture configurations typically utilize a barlow.

Please note the naming convention used for Daystar's ER filters. For instance, consider the example E-110N80:

• The letter E denotes an ER-Filter.
• The first number, such as 110 in the example, refers to the outer diameter of the dew cap (for refractors) or the tube (for SCTs) to which the ER filter is attached.
• N signifies On-Axis, indicating that the window is centered. Conversely, F represents Off-Axis, which is suitable for SC telescopes, positioning the window away from the center.
• The second number denotes the free passage, indicating the size of the window. In the example, it's 80 millimeters.

Please be aware that the actual product may vary from the image shown.

SPECIFICATIONS

Capacity:

Free Transmission (mm): 130

Diameter (mm): 180

Frame: Lens Filters

General:

Type: Solar Filters

Type of Build: ERF Pre-Filter