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DayStar 150mm ERF with 180mm Inside Diameter Cap

by DayStar
SKU E-180N150
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 180mm Inside Diameter Cap - For Refractor - E-180N150

Introducing the DayStar 150mm Solar Energy Rejection Filter, designed for refractor telescopes with an inside diameter cap of 180mm.

These cutting-edge filters have been meticulously engineered to dramatically reduce thermal stress on your telescope's filter assembly.

They achieve this by effectively either absorbing or reflecting ultraviolet and/or infrared light while seamlessly transmitting light within the desired visual spectrum.

You have the option to choose between two types of glass: Red or Yellow, or you can opt for dielectric materials that are effective in both the infrared and ultraviolet ranges.

These filters guarantee precise filtration while allowing the passage of the specific wavelengths you desire.

Notably, the Energy Rejection Filter also serves as an aperture mask, ensuring a direct angle of incidence for incoming light, which greatly enhances the efficiency of the filtration process.

For optimal performance, DayStar recommends using filter assemblies at a focal ratio of f/30 or slower.

Achieving this configuration is made effortless with the right Energy Rejection Filter and/or Barlow lens.

If you are working with higher resolution or larger aperture setups, including a Barlow lens is advised to enhance your overall 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:

  • To ensure a seamless fit for your ERF (Energy Rejection Filter), kindly specify the telescope you plan to use it with and take a precise measurement of the front-end dew shield's outer diameter using a ruler. This meticulous measurement is crucial, as each ERF is custom made to guarantee a perfect match.
  • Neglecting to provide this essential information may temporarily delay the processing of your order until we receive the required details. Your satisfaction and optimal performance is our priority.


Features & Highlights:

  • 150mm Energy Rejection Filter (ERF) Glass: A precision-engineered optical element created to effectively mitigate thermal effects on your filter assembly. Through adept absorption or reflection of UV and IR light, it exclusively permits the passage of the desired visual spectrum. This refined filtration technique ensures a consistently crisp viewing experience, reducing any potential disruptions stemming from thermal impacts.

  • Efficient Heat Load Reduction: The DayStar Energy Rejection Filter is engineered to significantly reduce the heat load on your filter assembly. By skillfully absorbing or reflecting UV and/or IR light, it exclusively allows light within the desired visual spectrum to pass through. This ensures a clear and consistent viewing experience, with minimal thermal interference.
  • Customizable Filtration Materials: Tailored to specific observational needs, this filter offers a variety of material options. Choose from Red or Yellow glass, or opt for dielectric coatings. Each option is adept at blocking unwanted UV and IR wavelengths, providing versatility aligned with your precise goals.
  • Enhanced Visual Clarity: While effectively screening out UV and IR, this filter excels in transmitting light within the desired visual spectrum. This unwavering commitment to optical clarity ensures that your observations remain characterized by precision, free from distortions, and unparalleled in their clarity.
  • Dual Role as Aperture Mask: In addition to its primary filtering function, the Energy Rejection Filter (ERF) serves as an aperture mask. This ensures that incoming light meets the telescope's optics at a direct and optimal angle, significantly enhancing the quality and precision of your observations.
  • Optimal Performance Configuration: DayStar recommends operating filter assemblies at f/30 or slower settings for peak performance. Achieving this setup is made simple with the inclusion of the appropriate ERF and/or barlow, ensuring perfect alignment within your telescope's optical system.
  • Comprehensive Compatibility and Personalized Support: DayStar provides a comprehensive list of compatible reflectors and refractors for easy selection. Should you have a specific telescope model in mind, their knowledgeable team is readily available to guide you towards the perfect filter for your equipment.
  • Critical Measurement Accuracy Requirement: To expedite customization, 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.
  • Durable and Protective Construction: The ERF is housed in a robust cell with a 180mm ID cap. This cap provides an extra layer of protection, safeguarding the filter when not in use, ensuring longevity and continued high performance.


                What's Included:

                ✓ DayStar 150mm ERF with 180mm ID Cap

                ✓ 5 Year Warranty



                SKU E-180N150
                Block Ultraviolet Yes
                Block Infrared Yes


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