Skip to content

Light pollution filters

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.

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

Specifications

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

Both halves of the specification

Ninety per cent at hydrogen alpha, the two oxygen lines, sulphur and hydrogen beta. Nought point one per cent at the sodium and mercury lines of street lighting. That pairing — what passes and what is rejected, each with named wavelengths — is what a filter specification ought to look like, and it is the only one on this shelf that provides it.

Why the named lamp lines matter

Sodium at 589 and 578 nanometres, mercury at 435. Those are the emissions of the lighting that produces the orange glow over a town, and a filter that rejects them specifically is doing something a broadband grey filter cannot.

What is still nowhere

Bandwidth. The transmission at each line is given; the width of the window around it is not. Two filters passing 90 per cent at 656 nm can differ considerably in how much surrounding sky they also let through.

Where it belongs

On an emission nebula, from a suburban or urban site, at low to medium magnification — or in front of an unmodified DSLR, which the maker names. On galaxies and clusters it removes as much of the object as of the sky.

Availability

German, French, Italian and Spanish Amazon stores ran from 46 € to 56 € on the day of the survey.

American Amazon store lists it in local currency, which the euro range above sets aside.

British Amazon catalogue holds a record for it that nobody is selling.

Figures as Keepa reported them on the day this page was last updated. Stock and pricing shift without warning.

Prices quoted in this text were read on 17 September 2026. The live price is at the top of the page.

What this fits

More light pollution filters

  • 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
  • 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

The rest of this rack

  • Diealles Shine black telescoping folding stool

    Diealles Shine Telescoping folding stool

    A polypropylene telescoping stool with a carry strap, described in five bullets that contain no measurement at all.

    Seat height range
    The listing gives none
    Adjustment method
    Not published by the maker.
    Steps
    The listing gives none
    Load rating
    The listing gives none — described as a large capacity
    Folded size
    The listing gives none
    Weight
    The listing gives none
    Foot design
    Not published by the maker.
    Seat material
    Polypropylene, described as an upgraded version
    Supplied accessories
    Supplied straps for hand or shoulder
    Amazon reference
    B0BWF25TX6 (same reference on 5 Amazon marketplaces)
    EAN
    0788135722737
    • The same telescoping principle as its better-documented rivals
    • Carry straps are supplied rather than sold separately
    • Not one measurement appears anywhere in the listing

    Best for: Nobody who has not seen one in person or measured what they need

    ≈ €20
    Check price on Amazon
  • Have A Seat telescoping stool in black with cushion

    Have A Seat HAS-001 telescoping stool

    An eleven-step telescoping stool reaching 45 cm with a 25 cm seat, a cushion and a bag, listed at 1.5 kg in its title and 1160 g in its bullets.

    Seat height range
    Eleven, reaching 45 cm
    Adjustment method
    A spring mechanism that engages each step, per the maker
    Steps
    Not published by the maker.
    Load rating
    Not given as a figure; described as carrying an average adult
    Folded size
    25 cm
    Weight
    The title says 1.5 kg; the fourth bullet says 1160 g. Both are reproduced here
    Foot design
    Not published by the maker.
    Seat material
    Described by the maker as patented
    Supplied accessories
    Seat cushion, bag and carry handle
    Amazon reference
    B09QMNJ4TW (same reference on 5 Amazon marketplaces)
    EAN
    4170000029076
    • Eleven steps to 45 cm covers the range a telescope actually needs
    • A spring mechanism that clicks into each step is quicker than a twist lock
    • The listing gives two different weights for the same stool

    Best for: An observer who wants a quick spring lock rather than a twist mechanism

    ≈ €35
    Check price on Amazon
  • Hesanzol portable telescoping stool with carry strap

    Hesanzol Portable telescoping stool

    A nylon and PA66 telescoping stool adjusting from 6.3 to 45 cm, rated to 180 kg, at a published 1.1 kg with a 25.9 cm seat.

    Seat height range
    6.3 cm to 45 cm, as the maker publishes it
    Adjustment method
    Two buckles, top and bottom, twisted to open and close
    Steps
    Not published by the maker.
    Load rating
    Up to 180 kg, as the maker states it
    Folded size
    25.9 cm, as the maker publishes it
    Weight
    1.1 kg, as the maker publishes it
    Foot design
    Non-slip underside
    Seat material
    High-strength nylon and PA66
    Supplied accessories
    Adjustable nylon strap and a storage bag
    Amazon reference
    B086ZJSTJX (same reference on 6 Amazon marketplaces)
    EAN
    0053552379766
    • The lightest stool on this shelf at a published 1.1 kg
    • Names its materials specifically rather than saying “plastic”
    • A 180 kg rating is lower than the 200 kg of two rivals here

    Best for: Carrying to a dark site on foot, where every hundred grams is counted

    ≈ $24 / £17 / €26
    Check price on Amazon

All light pollution filters