DAYSTAR OFF-AXIS ENERGY REJECTION FILTER FOR SCT
Daystar
DAYSTAR OFF-AXIS ENERGY REJECTION FILTER FOR SCT - 63mm ERF + 244mm cap is backordered and will ship as soon as it is back in stock.
DayStar Off-Axis SCT 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.
In order to find the right ERF for your system, measure (with a ruler) the outside (largest) diameter of your telescope tube at the very front of the telescope.
Variants
| 63 mm ERF with Ø 244mm internal diameter cap |
DS-E-244F63 |
|---|---|
| 80 mm ERF with Ø 281mm internal diameter cap | DS-E-281F80 |
| 80 mm ERF with Ø 311mm internal diameter cap | DS-E-311F80 |
| 90 mm ERF with Ø 325mm internal diameter cap | DS-E-325F90 |
| 100 mm ERF with Ø 356mm internal diameter cap | DS-E-356F100 |
| 115 mm ERF with Ø 410mm internal diameter cap | DS-E-410F115 |
| 125 mm ERF with Ø 460mm internal diameter cap | DS-E-460F125 |
