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July 1st: Store will be closed for Canada Day. Orders placed that day will ship on July 2nd.
July 1st: Store will be closed for Canada Day. Orders placed that day will ship on July 2nd.
ZWO UV/IR CUT Filter

ZWO UV/IR CUT Filter

by ZWO
SKU ZWO-IRCUT1.25
CA$31.00 - CA$69.00
CA$31.00
CA$31.00 - CA$69.00
CA$31.00
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  • Threads into standard 1.25" filter holders and nosepieces
  • Blocks unwanted ultraviolet (UV) and infrared (IR) wavelengths
  • Functions as a primary Luminance (L) filter for LRGB imaging
  • Essential for achieving sharp focus with color CMOS and CCD cameras
  • Includes a protective plastic storage case
2 in stock
Qualifies for FREE Shipping in Canada on orders over $500.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • ZWO 1.25" IR Cut-Off Filter

    The ZWO 1.25" IR Cut-Off Filter is an essential component for any color astrocamera, threading directly into a standard 31.75mm nosepiece or filter wheel. This single filter, backed by a 2-Year ZWO warranty, corrects for bloated stars and loss of detail by blocking the unfocused infrared light your sensor sees but your eye cannot.

    Restoring Image Sharpness at 1.25"

    A silicon camera sensor's sensitivity extends far beyond what the human eye can see, deep into the infrared (IR) spectrum. While your telescope's optics are designed to bring visible light to a sharp focus, they do not focus IR light at the same point. This mismatch results in a sharp visual image being overlaid with a soft, blurry IR image, causing fuzzy details and bloated stars. The ZWO 1.25" UV/IR Cut filter solves this by completely blocking these unwanted wavelengths, restoring the sharpness your optics are capable of delivering.

    Essential IR Protection for 31.75mm Imaging Systems

    This filter serves a critical dual role in any astrophotography setup. For any one-shot-color camera, it is the primary defense against IR contamination and is necessary for accurate color and sharp focus. For monochrome imagers, this filter is your Luminance (L) channel in an LRGB filter set, capturing all the detail of the visible spectrum. It also provides a vital protective function for specialized equipment, shielding expensive H-alpha solar filters from the damaging heat of focused infrared radiation during solar imaging.

  • Will the ZWO 1.25" UV/IR Cut filter improve my images of Jupiter with a ZWO ASI224MC camera?

    Yes, absolutely. Planetary imaging relies on capturing the finest possible details. Since your camera is highly sensitive to IR light that your telescope doesn't focus sharply, this filter removes the resulting blur, leading to much sharper views of Jupiter's cloud bands and the Great Red Spot.

    Do I need the ZWO 1.25" UV/IR Cut filter for deep-sky imaging of the Andromeda Galaxy (M31) with my color camera?

    Yes. While the effect can be more subtle than on planets, it is still essential for high-quality deep-sky images. The filter tightens star sizes across the entire frame and improves the final sharpness of dust lanes and galactic structure by eliminating the soft, unfocused IR signal that would otherwise wash out fine detail.

    What is the difference between this ZWO UV/IR Cut filter and a Luminance filter?

    For most astrophotography applications, they are functionally the same. A Luminance (L) filter's primary job is to pass the entire visible spectrum while blocking ultraviolet (UV) and infrared (IR) light. This ZWO 1.25" UV/IR Cut filter serves that exact purpose, making it the correct choice for the L-filter in an LRGB imaging sequence.

    My camera has an AR window. Do I still need the ZWO 1.25" UV/IR Cut filter?

    Yes. An Anti-Reflection (AR) window is designed only to maximize light transmission and prevent internal reflections. It does not block IR wavelengths. You still need a separate UV/IR Cut filter to prevent IR bloat and achieve a sharp image.

    Can I use the ZWO 1.25" UV/IR Cut filter for visual observing?

    You can, but you will not notice any difference in the view. The human eye is not sensitive to the infrared light this filter blocks. Its image-sharpening effect is only apparent when using a silicon-based camera sensor.

    How do I attach the ZWO 1.25" UV/IR Cut filter to my camera?

    The filter is housed in a standard 1.25" threaded cell. You can screw it directly onto the 1.25" nosepiece of your astronomy camera or into a dedicated slot in a 1.25" filter wheel.

  • SKU ZWO-IRCUT1.25
    Filter Class Single Filter
    Filter Type UV/IR Cut / Luminance
    Size 1.25" (31.75mm)
    Shape Round
    Mounting Threaded Cell
    Warranty 2 Years

    • ZWO IR-Blocking Filter in 1.25" Cell

      × 1

    • Plastic Filter Case

      × 1

  • ZWO 2-Year Limited Warranty