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Moon filters

Vixen Moon filter 1.25 in (37222-5)

Vixen's 1.25-inch Moon filter: a neutral density filter equivalent to ND4, which passes about a quarter of the light, with a 19 mm effective diameter, for eyepieces of 31.7 mm.

Vixen 1.25 inch moon filter

Vixen Moon filter 1.25 in (37222-5)

Vixen's 1.25-inch Moon filter: a neutral density filter equivalent to ND4, which passes about a quarter of the light, with a 19 mm effective diameter, for eyepieces of 31.7 mm.

Transmission percentage
About 25%, from the stated ND4 equivalence
Neutral or tinted dimming
Neutral density (ND), stated
Fixed or variable design
Fixed
Thread size
1.25 in (31.7 mm) eyepiece mount
Glass flatness
Not published in the Amazon.com listing.
Cell depth
0.2 in (5 mm) · 0.7 in (19 mm) effective diameter · 0.4 oz (10 g)
Amazon reference
B0018HILMI
EAN
4955295372225
  • Dimming factor published: ND4, about 25%
  • Neutral: no color tint
  • About $58 for a fixed Moon filter

Best for: A 1.25 in eyepiece case where a neutral, known dimming factor matters

≈ $58
Check price on Amazon

Specifications

Transmission percentage
About 25%, from the stated ND4 equivalence
Neutral or tinted dimming
Neutral density (ND), stated
Fixed or variable design
Fixed
Thread size
1.25 in (31.7 mm) eyepiece mount
Glass flatness
Not published in the Amazon.com listing.
Cell depth
0.2 in (5 mm) · 0.7 in (19 mm) effective diameter · 0.4 oz (10 g)
Amazon reference
B0018HILMI
EAN
4955295372225

ND4, stated

Vixen gives the dimming factor: equivalent to ND4, a neutral density filter that passes about a quarter of the light. Neutral means no color tint, so the Moon stays gray.

Dimensions

The filter is 0.2 inch (5 mm) deep, with a 19 mm effective diameter, weighs 10 g and mounts on 1.25-inch (31.7 mm) eyepieces.

When ND4 is right

At moderate magnifications on small and medium telescopes, a quarter of the light is comfortable on a gibbous or full Moon. For a large telescope at low power, a stronger or variable filter suits better.

The 19 mm aperture

On long-focus, wide-field eyepieces with large field stops, a 19 mm clear aperture can darken the edge of the view.

Price and availability

On November 7, 2026, Amazon.com listed it at about $58 from a third-party seller.

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 November 7, 2026. The live price is at the top of the page.

What gets asked before buying

What does ND4 mean?

A neutral density factor of 4: it passes one quarter of the light, about 25%. Neutral means it dims without tinting the view.

Is 25% enough for the full Moon?

For moderate magnifications, usually. At very low power on a large telescope, a stronger or variable filter such as the [Celestron variable](/accessories/moon-filters-celestron/) helps.

Will it vignette?

Its effective diameter is 19 mm. On eyepieces with a large field stop, the edge of the view may darken.

What barrel it suits

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    Transmission percentage
    Not published by the maker.
    Neutral or tinted dimming
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    Fixed or variable design
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    Thread size
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    Glass flatness
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    Cell depth
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    Amazon reference
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    EAN
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    Transmission percentage
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    Neutral or tinted dimming
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    Fixed or variable design
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    Thread size
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    Glass flatness
    Not published by the maker.
    Cell depth
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    Amazon reference
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    EAN
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    Battery type
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    Life
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    Window size
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    Alignment adjustment
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    Amazon reference
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    EAN
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    Life
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    Window size
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    Alignment adjustment
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    Amazon reference
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    EAN
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    Window size
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    EAN
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