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Useful against some lamps, and honest about the rest

The best light pollution filters for 2026

A light pollution filter blocks the wavelengths that street lighting emits and passes the rest, and how well that works depends entirely on what the street lights are. Against the old high-pressure sodium lamps, whose output sits in a few narrow bands, these filters were remarkably effective, and their reputation was built in those years. Against modern white LED street lighting, which emits across the whole visible spectrum, there is no narrow band to remove, and a filter that removes enough to matter removes the object with it. That is the honest starting point, and the maker who publishes a transmission curve rather than a claim is the one worth reading. What remains genuinely useful divides in two. For visual work, a broadband filter still lifts emission nebulae out of a bright sky, and does almost nothing for galaxies and clusters, for the same reason a nebula filter does not. For photographic work, the calculation changes: a filter that costs some signal but suppresses a strong gradient can make a stack far easier to process, and dedicated designs for colour cameras sit on this shelf. Every one of them introduces a colour cast that has to be corrected afterwards, and how severe that is belongs in the comparison. Read the thread size against the eyepiece or the camera nosepiece, and read whether the filter is specified for fast focal ratios, where the angle of the light through the coating shifts the band. We compare blocked wavelengths and published curve, LED and sodium behaviour, visual or photographic design, colour cast, thread size and focal ratio limits.

The parts here, column by column

  1. SVBONY 1.25 inch CLS light pollution filter

    SVBONY CLS 1.25 in (FUSF9155A)

    A CLS broadband filter publishing 90 per cent transmission at the hydrogen, oxygen and sulphur lines and 0.1 per cent at the sodium and mercury lines of artificial lighting.

    Blocked wavelengths and published curve
    90 % at Hα 656 nm, O-III 496 and 500 nm, S-II 672 nm and Hβ 486 nm, as the maker publishes it
    LED and sodium behaviour
    0.1 %, named at Na 589 and 578 nm and Hg 435 nm
    Visual or photographic design
    CLS broadband filter, threaded for 1.25 in eyepieces and camera noses
    Colour cast
    Planetary rotation coating system, for uniformity — the maker’s own description
    Thread size
    Not published by the maker.
    Focal ratio limits
    Not published by the maker.
    Amazon reference
    B079BWD595 (same reference on 6 Amazon marketplaces)
    EAN
    0609378745577
    • The only filter on this shelf to publish both in-band and off-band transmission with named wavelengths
    • The blocked lines are named by element, which is what allows the claim to be checked against physics
    • A broadband filter helps less than a narrowband one under heavy light pollution

    Best for: Imaging or observing emission nebulae from a town, with a colour camera or by eye

    ≈ $32 / €46
    Check price on Amazon
  2. Omegon Pro CLS 2 inch light pollution filter

    Omegon Pro CLS 2 in

    A 2 in broadband CLS filter that the maker states suits telescopes from 70 mm upwards and darkens the object only slightly.

    Blocked wavelengths and published curve
    The listing gives none as wavelengths
    LED and sodium behaviour
    Not published by the maker.
    Visual or photographic design
    CLS broadband filter, 2 in thread
    Colour cast
    Not published by the maker.
    Thread size
    Not published by the maker.
    Focal ratio limits
    From 70 mm, as the maker states it
    Amazon reference
    B016O66DY0 (same reference on 6 Amazon marketplaces)
    EAN
    4049467472919
    • The maker states a minimum aperture, which almost no filter listing does
    • A 2 in thread suits wide-field eyepieces and 2 in focal adapters
    • No wavelengths and no transmission percentage appear anywhere

    Best for: A 2 in eyepiece or focal adapter on a telescope of 70 mm or more, under a town sky

    ≈ £83 / €93
    Check price on Amazon
  3. K&F Concept Nano-X 67 mm natural night filter

    K&F CONCEPT Nano-X Natural Night 67 mm

    A 67 mm photographic light-pollution filter blocking the 580 to 610 nm region of common artificial lighting, with a 28-layer nano coating on both faces.

    Blocked wavelengths and published curve
    Approximately 580 to 610 nm, as the maker publishes it
    LED and sodium behaviour
    Not published by the maker.
    Visual or photographic design
    Screw-in filter for a camera lens — not a telescope filter
    Colour cast
    28 layers, double-sided nano coating per the maker · Japanese optical glass, double-side polished, per the maker
    Thread size
    67 mm
    Focal ratio limits
    Not published by the maker.
    Amazon reference
    B07PG785HC (same reference on 6 Amazon marketplaces)
    EAN
    6936069223248
    • The blocked region is published as a wavelength range rather than described
    • Double-sided coating reduces the ghosting that plagues bright-light nightscapes
    • It is a camera filter: it will not thread into an eyepiece or a telescope nose

    Best for: Wide-field tracked photography with a camera lens under sodium-lit skies

    ≈ £42 / €55
    Check price on Amazon

Any figure written into the body of this page was true on the day it was written. The amount shown next to each instrument is requested from the retailer as the page loads, and it is that amount, not the text, that stands.