Skip to content

DayStar 115mm Off-Axis ERF with 410mm Inside Diameter Cap

by DayStar
SKU E-410F115
Special Order
Original price $1,195.00 - Original price $1,195.00
Original price
$1,195.00 - $1,195.00
Current price $1,195.00

Lead-time: 2-4 weeks

Ships To: United States & Canada 🇺🇸 🇨🇦

✓ Free U.S. Shipping (on most orders over $150 USD)

✓ Price Match Available

✓ Authorized Dealer

✓ Bulk Order Discounts Available

✓ Questions? Call Us 1-800-860-3429

Shipping & Returns

We offer free U.S. shipping to the lower 48 States - on most orders over $150 USD. Some limitations may apply.

Shipping fees will apply on most orders shipping across Canada, with some exceptions.

We offer a 30 Day Return Policy on most of the products that we carry.

For full details on our Shipping & Returns Policy, please click here.


The vast majority of products that we sell, with a few exceptions, are covered under Warranty.

To view the Warranty details for each brand that we sell, including products that do not qualify for Warranty, please visit here.

DayStar 115mm Off-Axis Energy Rejection Filter with 410mm Inside Diameter Cap - for 14-inch SCT - E-410F115

Meet the DayStar 115mm Off-Axis Energy Rejection Filter with a 410mm Inside Diameter Cap, designed for use with 14-inch SCT telescopes.

These Energy Rejection Filters play a critical role in reducing the heat load on your filter assembly by either absorbing or reflecting harmful UV and/or Infrared (IR) light while allowing visible light to pass through.

They are typically crafted from red or yellow glass or use dielectric coatings to achieve this. In essence, they act as a barrier to undesirable wavelengths of light.

Additionally, the ERF can function as an aperture mask, ensuring that light enters the filter at the correct angle.

For optimal performance, DayStar filter assemblies work best at focal ratios (f-ratio) of f/30 or slower.

Achieving an f/30 configuration is made straightforward with the appropriate ERF or Barlow lens, enhancing the precision of your solar observations and photography.

 Important Instructions:

To facilitate a seamless integration, after your order is placed, please reach out to us via email with the following details:

  • Please indicate the telescope intended for ERF use and carefully measure the front dew shield's outer diameter using a ruler. This exact measurement is crucial, as ERFs are custom made for a precise fit.

  • Failure to provide this measurement might lead to a temporary delay in your order until we have the required information. Your satisfaction and optimal performance is our priority.

    Features & Highlights:

    • 115mm ERF Glass: Precision-crafted, the 115mm ERF aperture is tailor-made for optimal solar observation. It strikes a harmonious balance between light-gathering capacity and resolution, delivering clear, detailed views of solar phenomena.
    • 410mm Inside Diameter Cap: Included in the package is a 410mm inside diameter cap, ensuring a secure and snug fit with compatible telescopes. This cap plays a crucial role in minimizing stray light, enabling precise and unobstructed solar observations.
    • SCT Compatibility: Engineered specifically for 14-inch SCT (Schmidt-Cassegrain) telescopes, the ERF seamlessly integrates with your existing optical setup. This guarantees a seamless, hassle-free, and effective solar observation experience.
    • Advanced Energy Rejection: The ERF is meticulously designed to significantly reduce the heat load on your filter assembly. This is achieved through efficient absorption or reflection of UV and/or Infrared light, allowing the transmission of light within the desired visual spectrum.
    • Multi-Coated Optics: All optical surfaces are expertly multi-coated to enhance light transmission and minimize internal reflections. This results in vivid, high-contrast solar images with exceptional clarity and detail.
    • Off-Axis Design: The off-axis design provides an unobstructed view of the solar disk, maximizing the amount of light collected by the telescope. This design feature ensures precise observation of the sun's features.
    • Dual Functionality as an Aperture Mask: The ERF serves a dual purpose as an aperture mask, ensuring a direct angle of incidence for incoming light. This unique feature enhances filtering efficiency, ensuring that only the desired wavelengths are transmitted.
    • Robust Construction: Constructed from high-quality materials, the ERF guarantees durability and longevity. It is designed to withstand the rigors of outdoor use and maintain peak performance over time.
    • Recommendations for Optimal Performance: For the best results, DayStar recommends operating filter assemblies at f/30 or slower. This configuration is easily achieved with the appropriate ERF and/or Barlow. In cases of higher resolution or larger aperture configurations, the addition of a Barlow is recommended for an enhanced viewing experience.


                  What's Included:

                  ✓ DayStar 115mm Off-Axis ERF for 14-inch SCT

                   ✓ 5 Year Warranty



                  SKU E-410F115
                  Block Ultraviolet Yes
                  Block Infrared Yes

                  Customer Reviews

                  Be the first to write a review