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DayStar 100mm ERF with 120mm Inside Diameter Cap

by DayStar
SKU E-120N100
Special Order
Original price $695.00 - Original price $695.00
Original price
$695.00 - $695.00
Current price $695.00

Lead-time: 2-4 weeks

Ships To: United States & Canada 🇺🇸 🇨🇦

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

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DayStar 100mm Energy Rejection Filter with 120mm Inside Diameter Cap - for Refractors - E-120N100

Presenting the DayStar 100mm Energy Rejection Filter with 120mm Inside Diameter Cap - tailored for refractor telescopes.

These advanced filters are engineered to significantly reduce the heat strain on your filter assembly.

Achieving this by effectively absorbing or reflecting UV and/or I light, they flawlessly transmit light within the desired visual spectrum.

Available in variants of Red or Yellow glass, or utilizing dielectric IR and UV materials, these filters ensure precise filtration while permitting passage of desired wavelengths.

Notably, the ERF doubles as an aperture mask, ensuring a direct angle of incidence for incoming light, enhancing filtering efficiency.

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

This configuration is effortlessly attained with the right ERF and/or Barlow. In instances of higher resolution or larger aperture configurations, the inclusion of a Barlow is advised for an enhanced 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:

  • Specify the telescope intended for use with this ERF and meticulously measure the outer diameter of the telescope's dew shield at the front using a ruler. This precise measurement is paramount, as ERFs are custom made on an individual basis to ensure a perfect fit.
  • Failure to provide this measurement may result in a temporary hold on your order until the necessary information is retrieved. Your satisfaction and optimal performance is our priority.


Features & Highlights:

  • 100mm Energy Rejection Filter (ERF) Glass: Is a meticulously crafted optical element, thoughtfully designed to effectively manage thermal influences on your filter assembly. Through expert absorption or reflection of UV and IR light, it selectively permits only the desired visual spectrum to pass through. This deliberate filtration technique ensures a consistently crisp viewing experience, reducing any possible disturbances arising from thermal effects.

  • Heat Load Reduction: The DayStar Energy Rejection Filters excel in reducing the heat load on your filter assembly. Through efficient absorption or reflection of UV and/or IR light, these filters allow only light within the desired visual spectrum to pass through. This safeguards your telescope's optical components from excess heat, ensuring consistent and reliable performance.
  • Variety of Filter Materials: Tailor your observations to perfection with a range of filter material options. Whether it's Red or Yellow glass or specialized dielectric coatings, each is designed to selectively block unwanted UV and IR wavelengths. This flexibility allows for precise customization based on specific observational needs and goals.
  • Optical Clarity in the Visual Spectrum: While adept at blocking UV and IR, these filters excel in transmitting light within the desired visual spectrum. This guarantees that observations and captured images are free from distortions, optimizing clarity and precision in every detail.
  • Aperture Mask Functionality: The ERF (Energy Rejection Filter) serves a dual purpose as an aperture mask. By ensuring incoming light strikes the telescope's optics at a direct and optimal angle, this feature significantly enhances the quality of observations, further elevating your celestial experience.
  • Optimal Operating Conditions: DayStar filter assemblies operate at their peak performance when configured at f/30 and slower settings. Achieving this configuration is effortlessly accomplished with the incorporation of the appropriate ERF and Barlow, guaranteeing perfect alignment of your telescope's optical system.
  • Custom Compatibility: Should you have a specific telescope model in mind, the knowledgeable DayStar team stands ready to guide you towards the ideal filter for your equipment, ensuring seamless integration.
  • Precision Machining: Highlighting meticulous attention to detail, ERFs are custom machined on a one-off basis. This precision in manufacturing ensures the filter is tailored precisely to your telescope's unique requirements, guaranteeing a seamless and accurate fit.
  • Measurement Accuracy Requirement: To expedite the customization process, DayStar kindly requests an accurate measurement of the outer (largest) diameter of your telescope's dew shield at the foremost end. The precision of this measurement is pivotal in ensuring the perfect fit and performance of your ERF, underscoring DayStar's commitment to your optimal viewing experience
  • Sturdy and Safeguarding Build: Housed within a durable cell with a 120mm ID cap, the ERF gains an additional shield. This cap acts as an extra layer of defense, preserving the filter during periods of non-use, thereby ensuring its long-lasting durability and sustained high-level performance.


    What's Included:

    ✓ DayStar 100mm ERF with 120mm ID Cap

     ✓ 5 Year Warranty



    SKU E-120N100
    Block Ultraviolet Yes
    Block Infrared Yes

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