{"product_id":"zwo-d25-uv-ir-cut-protective-window","title":"ZWO D25 UV IR-Cut Protective Window","description":"\u003ch3\u003e\u003cstrong\u003eProduct Overview\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThe \u003cstrong\u003eZWO D25 UV IR-Cut Protective Window\u003c\/strong\u003e is a \u003cstrong\u003e25 mm\u003c\/strong\u003e replacement window for ZWO ASI cameras. It is \u003cstrong\u003e1.1 mm\u003c\/strong\u003e thick, figured to \u003cstrong\u003e1\/4 λ flatness\u003c\/strong\u003e, and mounts directly in front of the sensor. It seals the sensor chamber against dust and humidity while blocking ultraviolet and infrared outside the visible band.\u003c\/p\u003e\n\u003cp\u003eThis is a consumable spare and a conversion part, not an upgrade to image quality on its own.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eWho It's For\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eThis is a good match if you own an \u003cstrong\u003eASI174-series camera\u003c\/strong\u003e — ASI174MM, ASI174MC, ASI174MM-COOL, or ASI174MC-COOL — and need to replace a scratched or contaminated window.\u003c\/p\u003e\n\u003cp\u003eIt is also the part ZWO specifies if you own an \u003cstrong\u003eASI485MC\u003c\/strong\u003e, which ships with the D25 AR window, and want to convert it to IR-cut at the sensor rather than carrying a UV\/IR-cut filter in the imaging train.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eKey Features \u0026amp; Design\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e25 mm diameter, 1.1 mm thick:\u003c\/strong\u003e the D25 form factor used on ASI174-series and ASI485MC bodies\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUV IR-cut coating:\u003c\/strong\u003e passes visible light and rejects ultraviolet and infrared, unlike the AR window, which passes both\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1\/4 λ flatness:\u003c\/strong\u003e the window sits in a converging beam directly ahead of the sensor, so surface figure feeds straight into star shapes\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDust and humidity seal:\u003c\/strong\u003e the window is the sensor chamber's only physical barrier\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoated optical glass\u003c\/strong\u003e, supplied as a bare window\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eRecommended Uses\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacing a scratched or contaminated window\u003c\/strong\u003e on any ASI174-series camera\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConverting an ASI485MC from AR to IR-cut\u003c\/strong\u003e, which is ZWO's own stated use for this part\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePlanetary and lunar imaging through refractors\u003c\/strong\u003e, where uncorrected infrared focuses at a different point than visible light and softens detail\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOne-shot-colour imaging with no filter in the train\u003c\/strong\u003e, where infrared leakage shifts colour and bloats stars\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eCompatibility and Accessory Notes\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCameras shipped with this window:\u003c\/strong\u003e ASI174MM, ASI174MC, ASI174MM-COOL, and ASI174MC-COOL\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eASI485MC conversion:\u003c\/strong\u003e the ASI485MC ships with the D25 AR window; ZWO names the D25IR-CUT as the correct IR-cut replacement for it\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDiameter is not interchangeable:\u003c\/strong\u003e D25 fits 25 mm bodies only. Smaller planetary bodies take the D21; ASI1600 \/ ASI294 \/ ASI183 \/ ASI533 take the D32; ASI6200 \/ ASI2400 \/ ASI2600 take the D60\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo installation direction:\u003c\/strong\u003e ZWO confirms the window has no preferred orientation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacement procedure:\u003c\/strong\u003e see ZWO's official guide, \u003ca href=\"https:\/\/i.zwoastro.com\/wp-content\/uploads\/2025\/12\/c36da643469647ac8334179b49aa8b11.pdf\" target=\"_blank\" rel=\"noopener\"\u003eHow to Replace the Camera Protective Window\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMechanical part only\u003c\/strong\u003e — no electronic function, no camera communication\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eImportant Limitations\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eThis is a bare optical window, not a threaded filter.\u003c\/strong\u003e It only works installed inside the camera body\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplacement means opening the sensor chamber.\u003c\/strong\u003e Dust introduced during the swap lands on or near the sensor — work in still, clean air\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIt will defeat infrared imaging.\u003c\/strong\u003e If you shoot IR-pass or methane-band planetary work, this window blocks exactly the light you want. Use the D25 AR instead\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot a light-pollution or narrowband filter\u003c\/strong\u003e — it cuts UV and IR only\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFits 25 mm bodies only.\u003c\/strong\u003e Check your camera against the list above before ordering\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSold as a single window.\u003c\/strong\u003e No tools, gaskets, or retaining ring included\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhich cameras use the D25 UV IR-cut window?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eZWO fits it to the ASI174MM, ASI174MC, ASI174MM-COOL, and ASI174MC-COOL. It is also the specified IR-cut conversion window for the ASI485MC.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eI have an ASI485MC — is this the right part?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes, if you want IR-cut at the sensor. The ASI485MC ships with the D25 AR window, and ZWO names the D25IR-CUT as its IR-cut replacement.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is the difference between the AR window and the UV IR-cut window?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe AR window is anti-reflective coated but optically clear and passes UV and IR. This one blocks both. ZWO confirms the AR window does not cut UV.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo I still need a UV\/IR-cut filter in my imaging train?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNot for that purpose. With this window installed the IR-cut happens at the sensor, which frees a filter drawer or wheel slot.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the window have to face a particular direction?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. ZWO confirms there is no specific installation direction.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I still do infrared planetary imaging with this fitted?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo — that is the one thing it rules out. An IR-pass or methane-band filter needs infrared to reach the sensor, and this window stops it. Keep or fit the D25 AR for that work.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill this fit my ASI1600 or ASI294?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. Those bodies use the 32 mm D32 window. This is 25 mm.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this good for beginners?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe part is simple, but fitting it means opening the sensor chamber. If you are not confident working clean, have it done rather than risk dust on the sensor.\u003c\/p\u003e\n\n\u003ch3\u003e\u003cstrong\u003eBottom Line\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003eIn short: a 25 mm × 1.1 mm UV IR-cut window at 1\/4 λ flatness — the correct spare for the ASI174 series and ZWO's specified IR-cut conversion for the ASI485MC. It rules out infrared imaging by design; if you need that, use the D25 AR.\u003c\/p\u003e","brand":"ZWO Optical","offers":[{"title":"Default Title","offer_id":53804450873455,"sku":"D25IR-CUT","price":23.0,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0686\/0049\/6239\/files\/426474105bc9afcb1261044235a281b3-1_3793fb17-3951-4b93-b19c-b63bda49cfac.jpg?v=1784083502","url":"https:\/\/ontariotelescope.com\/products\/zwo-d25-uv-ir-cut-protective-window","provider":"Ontario Telescope and Accessories","version":"1.0","type":"link"}