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DayStar 150mm ERF with 220mm Inside Diameter Cap

by DayStar
SKU E-220N150
Special Order
Original price $1,645.00 - Original price $1,645.00
Original price
$1,645.00 - $1,645.00
Current price $1,645.00

Lead-time: 2-4 weeks

Ships To: United States & Canada 🇺🇸 🇨🇦

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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 150mm Energy Rejection Filter with 220mm Inside Diameter Cap - For Refractor - E-220N150

The DayStar 150mm Energy Rejection Filter with a 220mm Inside Diameter Cap, specifically designed for refractor telescopes.

These cutting-edge filters are crafted to greatly alleviate the thermal stress on your filter system.

They accomplish this by efficiently absorbing or reflecting UV and/or I light, ensuring seamless transmission of light within the desired visual spectrum.

You can choose from variants featuring Red or Yellow glass, or opt for filters made with dielectric IR and UV materials.

These filters guarantee precise filtration while allowing the passage of desired wavelengths.

Remarkably, the ERF also serves as an aperture mask, guaranteeing a direct angle of incidence for incoming light, thereby enhancing filtering efficiency.

For optimal performance, DayStar recommends operating filter assemblies at f/30 or slower.

Achieving this setup is easily accomplished with the appropriate ERF and/or Barlow.

In cases of higher resolution or larger aperture configurations, incorporating a Barlow is recommended for an enriched viewing experience.

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 you plan to use in conjunction with this ERF and carefully gauge the outer diameter of the telescope's dew shield at the front using a ruler. This exact measurement is crucial, as ERFs are custom-made to fit each telescope precisely.
  • If this measurement is not provided, it may lead to a temporary delay in processing your order until the required information is received. Your satisfaction and optimal performance is our priority.


Features & Highlights:

  • 150mm Energy Rejection Filter (ERF) Glass: A meticulously crafted optical component designed to efficiently manage thermal impacts on your filter assembly. It achieves this by skillfully absorbing or reflecting UV and IR light, allowing only the desired visual spectrum to pass through. This strategic filtration process guarantees a consistently clear viewing experience, minimizing any potential disruptions caused by thermal effects.

  • Efficient Thermal Management: The DayStar Energy Rejection Filter is intricately designed to significantly mitigate thermal effects on your filter assembly. Through adept absorption or reflection of UV and IR light, it selectively permits only the desired visual spectrum, ensuring a consistently clear viewing experience and minimizing any thermal disruptions.
  • Tailored Filtration Options: This filter is customized to meet specific observational requirements, offering a versatile range of material choices. Whether you opt for Red or Yellow glass or choose dielectric coatings, each option excels in effectively blocking unwanted UV and IR wavelengths. This adaptability seamlessly aligns with your precise objectives.
  • Unwavering Optical Precision and Clarity: While effectively screening out UV and IR, this filter distinguishes itself by transmitting light exclusively within the desired visual spectrum. This steadfast commitment to optical clarity guarantees that your observations maintain precision, free from distortions, and unparalleled in their clarity.
  • Enhanced Aperture Mask Functionality: Beyond its primary filtering function, the Energy Rejection Filter (ERF) also serves as an aperture mask. This ensures that incoming light meets the telescope's optics at a direct and optimal angle, significantly elevating the quality and precision of your observations.
  • Optimized Performance Configuration: DayStar recommends configuring filter assemblies at f/30 or slower settings for optimal performance. Achieving this setup is a straightforward process with the inclusion of the appropriate ERF and, if needed, a Barlow. This ensures seamless integration within your telescope's optical system.
  • Comprehensive Compatibility and Expert Guidance: DayStar provides an extensive selection of compatible reflectors and refractors, streamlining your selection process. If you have a specific telescope model in mind, their experienced team is readily available to assist you in finding the perfect filter for your equipment.
  • Critical Precision in Measurement Requirement: To streamline the customization process, it is crucial to specify the telescope model and provide an accurate measurement (using a ruler) of the outer (largest) diameter of your telescope's dew shield at the front. This precision is paramount, as each ERF is individually machined to ensure seamless integration with your telescope.
  • Robust and Protective Construction: The ERF is securely housed in a sturdy cell with a 200mm ID cap. This additional layer of protection ensures the filter's longevity and sustained high performance by safeguarding it when not in use.


                        What's Included:

                        ✓ DayStar 150mm ERF with 220mm ID Glass

                        ✓ 5 Year Warranty



                        SKU E-220N150
                        Block Ultraviolet Yes
                        Block Infrared Yes


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