Energy Rejection Filters

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All sales of solar gear are final, so please choose your filter carefully and reach out with any questions. Description Energy Rejection Filters reduce the heat load on your filter assembly by absorbing or reflecting UV and/or I light and transmitting light in the desired visual spectrum. These filters are sometimes Red or Yellow glass, or dielectric IR and UV, but pass light in the desired visual spectrum. The ERF can also serve as an aperture mask to accomplish a straight angle of incidence for light entering the filter. DayStar filter assemblies operate best at f/30 and slower. Creating f/30 configuration can be done easily with the proper ERF and/or barlow as listed below. Higher resolution, larger aperture configurations use a barlow. Scope focal length mm inches x Barlow power 2x 2.5x4x = USEUSEABLE CLEAR APERTURE AND ERF SIZE IN MM 30 In order to compute the proper aperture reduction mask, divide your telescope EFL or Focal Length by 30. To compute the proper aperture using a barlow, use the adjusted EFL which includes multiplication by your barlow. Application SKU # Specification Price Energy Rejection-Refractor DSIUV2 Daystar 2" UV/IR Filter - For refractor $125.00 Energy Rejection-Refractor E-100N75 75mm ERF Glass, Cell & 100mm ID Cap - For refractor $402.00 Energy Rejection-Refractor E-110N75 75mm ERF Glass, Cell & 110mm ID Cap - For refractor $402.00 Energy Rejection-Refractor E-110N80 80mm ERF Glass, Cell & 110mm ID Cap - For refractor $460.00 Energy Rejection-Refractor E-120N80 80mm ERF Glass, Cell & 120mm ID Cap - For refractor $460.00 Energy Rejection-Refractor E-120N100 100mm ERF Glass, Cell & 120mm ID Cap - For refractor $580.00 Energy Rejection-Refractor E-130N100 100mm ERF Glass, Cell & 130mm ID Cap - For refractor $580.00 Energy Rejection-Refractor E-140N100 100mm ERF Glass, Cell & 140mm ID Cap - For refractor $580.00 Energy Rejection-Refractor E-150N100 100mm ERF Glass, Cell & 150mm ID Cap - For refractor $580.00 Energy Rejection-Refractor E-150N130 130mm ERF Glass, Cell & 150mm ID Cap - For refractor $862.00 Energy Rejection-Refractor E-160N130 130mm ERF Glass, Cell & 160mm ID Cap - For refractor $862.00 Energy Rejection-Refractor E-170N130 130mm ERF Glass, Cell & 170mm ID Cap - For refractor $862.00 Energy Rejection-Refractor E-170N140 140mm ERF Glass, Cell & 170mm ID Cap - For refractor $1,055.00 Energy Rejection-Refractor E-180N130 130mm ERF Glass, Cell 180mm ID Cap - For refractor $1,055.00 Energy Rejection-Refractor E-180N150 150mm ERF Glass, Cell & 180mm ID Cap - For refractor $1,175.00 Energy Rejection-Refractor E-190N130 130mm ERF Glass, Cell & 190mm ID Cap - For refractor $875.00 Energy Rejection-Refractor E-190N150 150mm ERF Glass, Cell & 190mm ID Cap - For refractor $1,175.00 Energy Rejection-Refractor E-200N140 140mm ERF Glass, Cell & 200mm ID Cap - For refractor $1,035.00 Energy Rejection-Refractor E-200N150 150mm ERF Glass, Cell & 200mm ID Cap - For refractor $1,175.00 Energy Rejection-Refractor E-210N150 150mm ERF Glass, Cell & 210mm ID Cap - For refractor $1,175.00 Energy Rejection-Refractor E-220N150 150mm ERF Glass, Cell & 220mm ID Cap - For refractor $1,175.00 Energy Rejection - SCT 8" E-244F63 63mm ERF Glass, Cell & 244mm ID Cap - off-axis for SCT $402.00 Energy Rejection - SCT 9.25" E-281F80 80mm ERF Glass, Cell & 281mm ID Cap - off-axis for SCT $460.00 Energy Rejection - SCT 10" E-311F80 80mm ERF Glass, Cell & 311mm ID Cap - off-axis for SCT $460.00 Energy Rejection - SCT 11" E-325F90 90mm ERF Glass, Cell & 311mm ID Cap - off-axis for SCT $518.00 Energy Rejection - SCT 12" E-356F100 100mm ERF Glass, Cell & 356mm ID Cap - off-axis for SCT $633.00 Energy Rejection - SCT 14" E-410F115 115mm ERF Glass, Cell & 410mm ID Cap - off-axis for SCT $690.00 Energy Rejection - SCT 16" E-460F125 125mm ERF Glass, Cell & 460mm ID Cap - off-axis for SCT $875.00 Show more