--- product_id: 218266086 title: "Astromania 1.25\" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects" brand: "astromania" price: "€ 155.13" currency: EUR in_stock: true reviews_count: 5 category: "Astromania" url: https://www.desertcart.com.cy/products/218266086-astromania-1-25-o-iii-filter-enhances-contrast-during-visual store_origin: CY region: Cyprus --- # 1.25" O-III narrowband filter 95% transmission of O-III lines (496-501nm) Anti-reflection & dichroic coatings Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects **Brand:** astromania **Price:** € 155.13 **Availability:** ✅ In Stock ## Summary > 🌠 See the unseen: Unlock nebula secrets with Astromania’s O-III filter! ## Quick Answers - **What is this?** Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects by astromania - **How much does it cost?** € 155.13 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.com.cy](https://www.desertcart.com.cy/products/218266086-astromania-1-25-o-iii-filter-enhances-contrast-during-visual) ## Best For - astromania enthusiasts ## Why This Product - Trusted astromania brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Universal 1.25" Fit:** Seamlessly integrates with any telescope eyepiece for instant upgrade. - • **Astro-Verified Quality:** Individually inspected with transmittance percentage inscribed—precision you can trust. - • **Light Pollution Slayer:** Blocks all other visible wavelengths, making faint nebulae pop against the night sky. - • **Pinpoint Nebula Contrast:** Isolates double ionized oxygen lines for razor-sharp nebula views even in light-polluted skies. - • **Premium Optical Coatings:** Anti-reflection and dichroic layers eliminate glare and ghosting for crystal-clear observation. ## Overview The Astromania 1.25" O-III Filter is a high-grade narrowband filter designed to enhance contrast by isolating the double ionized oxygen emission lines (496-501nm). Compatible with all 1.25" eyepieces, it dramatically improves visual observation of faint gaseous and planetary nebulae under any sky conditions, including light-polluted urban areas. Featuring advanced anti-reflection and dichroic coatings, it blocks unwanted wavelengths to deliver crisp, high-contrast views of iconic nebulae like the Veil, Ring, Dumbbell, and Orion. Each filter is individually tested and marked for precise light transmittance, making it a must-have for serious amateur astronomers and astrophotographers seeking to elevate their night sky experience. ## Description The Astromania 1.25" O-III Filter is comparable to the Astromania UHC filter in its function. The difference is that this filter only allows the light of doubly ionized oxygen through. This means that there is an enormous increase in contrast with diffuse, planetary and extremely dim nebulae. This is a special narrowband filter which allows an even smaller range of wavelengths than the Astromania UHC filter. Even so, there are innumerable astronomical objects which can be first observed in detail with this filter or cannot be seen at all without it. A prime example is the Veil nebula in the constellation of Cygnus. It's a great accessory for observations of nebulae due to its capability to suppress all light that lies outside its 4960-5010 angstrom (496-501 nm) passband. This filter can be used for astrophotography as well. The O-III 1.25" Filter has a standart barrel diameter so you can use it with a telescope of any brand. Note that this filter gives a green tint to observed objects. The O-III provides an even greater contrast boost on some objects than the UltraBlock narrowband filter. And for nebulas, every little bit helps! It substantially improves contrast and outperforms the UHC for most planetary nebulae while on apertures of 10" or more, it outperforms the UHC filter for all types of nebulae. The Astromania 1.25" O-III Filter isolates just the two doubly ionized oxygen lines (496 and 501nm lines) emitted by diffuse, planetary and extremely faint nebulae. Thus, these faint objects become much more visible against the blackened background of space. The Astromania 1.25" O-III Filter produces near-photographic views of the Veil, Ring, Dumbbell and Orion nebula, among many other objects. Performs well under both light-polluted and dark skies. Review: The published spectral transmission plot shows only the visible light range. If you're using this on a monochrome camera without an IR-block filter, be aware this filter does not attenuate IR very much, in fact it has more transmission at 840 and 920 nm than it does in the nominal passband of 500-520 nm. Attached plot of absorbance was taken with an Ocean Optics USB2000 spectrometer. Review: Using this excellent quality filter for a Unistellar Telescope. It does as it is supposed to do. Very satisfied with it. ## Features - 1.25 inch O-III Filter greatly enhances contrast during visual observation of gaseous and planetary nebulae in all sky condition; allows high-contrast imaging even in areas with strong light pollution - Especially useful for large aperture telescopes through which the light of the Moon can be extremely overwhelming; allowing just for the Double Ionized Oxygen lines between 496nm to 501nm to pass through at 95 percent - Completely blocks virtually all other visible wavelengths of light so views of nebulas are optimized; increases contrast through selective filtration-Anti-reflection coated to prevent glaring and ghosting - Not only useful at light-polluted sites; the contrast is also increased at dark sky sites; can be used with all 1.25 inch eyepieces; filter made from high-grade glass with dichroic interference and antireflection coatings - Each Astromania 1.25inch O-III Filter is individually inspected and proudly inscribed with the percentage of light transmittance of the two O-III emission lines ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0141U979O | | Brand | Astromania | | Colour | 1.25" O-III | | Customer Reviews | 4.4 4.4 out of 5 stars (90) | | Date First Available | 18 Aug. 2015 | | Focus type | manual | | Guaranteed software updates until | unknown | | Item Weight | 0.3 Ounces | | Item model number | SKU_AM_OF1 | | Package Dimensions L x W x H | 7.5 x 7.4 x 2.2 centimetres | | Package Weight | 0.03 Kilograms | | Part number | SKU_AM_OF1 | | Photo Filter Effect Type | Enhancing | | Photo Filter Thread Size | 3.2 Centimetres | | Product Dimensions L x W x H | 5.4 x 4.4 x 1.9 centimetres | | Size | 1.25" | | Water Resistance Level | Not Water Resistant | ## Product Details - **Brand:** Astromania - **Coating description:** Antireflection Coating - **Material:** Glass - **Photo Filter Size:** 31.75 Millimeters - **Photo filter effect type:** Enhancing - **Photo filter thread size:** 3.2 Centimetres - **Product dimensions:** 32L x 32W millimetres - **Set Name:** 1.25 Inch O-III Filter Set - **Water resistance level:** Not Water Resistant ## Images ![Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Image 1](https://m.media-amazon.com/images/I/71+VANg7S8L.jpg) ![Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Image 2](https://m.media-amazon.com/images/I/71XTYbdeKKL.jpg) ![Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Image 3](https://m.media-amazon.com/images/I/71g68gPE47L.jpg) ![Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Image 4](https://m.media-amazon.com/images/I/71CMy6ZHthL.jpg) ![Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Image 5](https://m.media-amazon.com/images/I/81vCBV1siCL.jpg) ## Available Options This product comes in different **Size** options. ## Customer Reviews ### ⭐⭐⭐⭐ Review *by A***R on 16 October 2024* The published spectral transmission plot shows only the visible light range. If you're using this on a monochrome camera without an IR-block filter, be aware this filter does not attenuate IR very much, in fact it has more transmission at 840 and 920 nm than it does in the nominal passband of 500-520 nm. Attached plot of absorbance was taken with an Ocean Optics USB2000 spectrometer. ### ⭐⭐⭐⭐⭐ Review *by J***R on 18 April 2024* Using this excellent quality filter for a Unistellar Telescope. It does as it is supposed to do. Very satisfied with it. ### ⭐⭐⭐⭐ Review *by A***R on 3 December 2025* Good item . ## Frequently Bought Together - Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects - Astromania 1.25" UHC (Ultra High Contrast) Filter - Superb Views of The Orion, Lagoon, Swan and Other Extended Nebulae - Astromania 1.25" H-Alpha Night Sky Filter --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.com.cy/products/218266086-astromania-1-25-o-iii-filter-enhances-contrast-during-visual](https://www.desertcart.com.cy/products/218266086-astromania-1-25-o-iii-filter-enhances-contrast-during-visual) --- *Product available on Desertcart Cyprus* *Store origin: CY* *Last updated: 2026-04-23*