They pass the lines the gas emits and block the rest · review
A UHC filter whose published features include a first-person account of seeing the Orion nebula — and no wavelength anywhere.
The sixth of eight published features, in the first person.
That the Orion nebula is visible now where it was not before. That it is very faint. That Betelgeuse is an unexpected favorite, because its color shows so much better.
It reads as a customer review set among the bullets, and it is the only text on this listing that says what looking through the filter is like.
This page prints it as a published feature and takes no position on it. No other page on either half of this shelf carries anything comparable.
The thread, named rather than implied.
An inch figure describes the barrel; a thread specification describes what screws together. One and a quarter inches is 31.75 mm (1.25 in), and the thread cut inside it is M28.5 × 0.6.
On a shelf where one listing advertises stacking filters, that is the difference between two of them meeting and two of them not.
Claimed here and nowhere else on this shelf.
Filters live in cases and come out into dew. A coating that does not mark when a drop lands on it is a real thing to want, and no figure or test accompanies the claim.
“Uniform layer”, on the same line, does not say how many layers there are or which faces carry them.
Emission nebulae, planetary nebulae and supernova remnants.
That is exactly the set a UHC filter helps, because those three radiate in lines rather than across the spectrum. Galaxies and star clusters do not, and a UHC removes their light along with the sky glow.
This listing names the right three. It does not name the lines it passes to do it.
Six filters on this shelf now carry the UHC designation. None publishes its window.
The two that publish wavelengths — 496 and 501 nm — are oxygen narrowband filters, which is the opposite category: a slice rather than a window.
So on both halves of this shelf, UHC remains a name.
American Amazon store sat at about $23 on the day of the survey.
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 October 7, 2026. The live price is at the top of the page.
Same aisle, closest price — what the same spend else shows.
| Bandpass and type | UHC — a market convention, not a published standard · No wavelength, window or bandwidth appears anywhere on the listing · Stated to selectively reduce the transmission of certain wavelengths, especially those produced by artificial light |
|---|---|
| Line transmission | Not published by the maker. · High light transmittance is claimed without a figure |
| Blocking outside the band | Not published by the maker. |
| Thread size | 1.25 in, standard thread named as M28.5 × 0.6 mm (0.20 × 0.02 in), stated compatible with astronomical eyepieces and electronic eyepieces by rotary docking |
| Glass flatness | Not published by the maker. · High-transparency optical glass is stated |
| Coatings | A uniform layer, stated, with ultrasonic cleaning and dust removal and a waterproof coating · The number of layers and the faces treated are not given · Aluminum alloy, stated lightweight and durable |
| Amazon reference | B0D4JV2ZRQ |
| EAN | 0764126140643 |
It is the sixth of eight published features, written in the first person: that the Orion nebula is now visible where it was not before, that it is very faint, and that Betelgeuse is an unexpected favorite because its color shows better. It reads as a customer review placed among the bullets. This page prints it as what it is — a published feature of the listing — and takes no position on it. No other page on either half of this shelf carries anything like it, and it is the only text on this listing that describes what looking through it is like.
Yes, because an inch figure describes the barrel and a thread specification describes what actually screws together. One and a quarter inches is 31.75 mm (1.25 in); the thread cut inside it is M28.5 × 0.6. Three listings on this shelf name it that way and the rest give only the inch size. On a shelf where filters are stacked — one listing here advertises exactly that — knowing the thread is the difference between two filters meeting and two filters not.
Nothing published. It is a market convention describing an intention: a window wide enough to take in several emission lines at once. Six filters on this shelf now carry the designation and not one of them publishes the window. The two filters here that do publish wavelengths in nanometers are both oxygen narrowband filters, which is the opposite category — a narrow slice rather than a wide window. So the designation remains, across both halves of this shelf, a name rather than a specification.
This model is listed on Amazon.com, at ≈ $23 at the last reading. Listed is not the same as in stock: availability changes daily, and the buy box shows the live price.
Details checked on October 7, 2026.
A first nebula filter for a light-polluted sky, bought on price with the specification taken on trust
Specifications: the manufacturer sheet for telescopes and observing optics and the matching Amazon product page. Prices and availability: Keepa. Every figure on this page names its source.
H-alpha narrowband · 1.25 in · hardened multi-coatings · no bandwidth published
A narrowband hydrogen-alpha filter whose bandwidth — the one figure that defines a narrowband filter — is never published.
Best for: Imaging hydrogen regions, by somebody who will ask the seller for the bandwidth before buying
≈ $70
UHC · 1.25 in standard thread · optical glass in an aluminum frame · anti-reflection coatings · no passband published
A UHC filter that explains correctly what the category does, names the nebulae it suits, and publishes no wavelength at all.
Best for: An observer in a suburban sky who wants the effect explained before buying, and will take the glass on trust
≈ $32
OIII narrowband · 496 and 501 nm published · 1.25 in · two-year US warranty
An oxygen III filter that publishes the two lines it isolates in nanometers — and lists its package weight among its features.
Best for: Planetary nebulae and supernova remnants from a suburban garden, on a 1.25 in eyepiece
≈ $80
