Product Overview The ZWO D32 AR Protective Window is a 32 mm replacement window for ZWO ASI cameras. It is 2 mm thick — nearly double the 1.1 mm of the smaller D21 and D25 windows — figured to 1/4 λ flatness, and carries an anti-reflective coating. It sits directly in front of the sensor and seals the sensor chamber against dust and humidity. ZWO produces the D32 in AR only. There is no D32 UV IR-cut window. If you need IR-cut on a D32-bodied camera, it has to happen in the imaging train — see the limitations below. Who It's For This is a good match if you own a D32-bodied ASI camera — the ASI1600, ASI294, ASI183, ASI533, ASI585, ASI990, or ASI991 series — and need to replace a window that is scratched, fogged, or contaminated beyond cleaning. Because there is no IR-cut alternative in this diameter, this is simply the window for these bodies rather than a choice between two coatings. Key Features & Design 32 mm diameter, 2 mm thick: the D32 form factor, covering ZWO's 4/3" and 1" class sensors Anti-reflective coating: reduces reflection losses and internal glare at the window surfaces, a common origin of halos around bright stars Optically clear: passes UV and IR straight through — all wavelength control happens in your imaging train 1/4 λ flatness: the window sits in a converging beam directly ahead of the sensor, so surface figure feeds straight into star shapes 2 mm substrate: thicker glass than the D21 and D25 windows, matched to the larger clear aperture Dust and humidity seal: the window is the sensor chamber's only physical barrier Recommended Uses Replacing a scratched or contaminated window on an ASI1600, ASI294, ASI183, ASI533, ASI585, ASI990, or ASI991 Monochrome deep-sky imaging, where a filter wheel handles all wavelength selection anyway Narrowband imaging, where you want no extra coating shaping the passband Infrared and methane-band planetary imaging, which requires infrared to reach the sensor One-shot-colour imaging with a UV/IR-cut filter carried in a drawer, wheel, or threaded ahead of the camera Compatibility and Accessory Notes Match models: ASI1600 series, ASI294 series, ASI183 series, ASI533 series, ASI585 series, ASI990 series, and ASI991 series ASI585 Air is not included in the D32 match list — ZWO calls that exception out specifically Diameter is not interchangeable: D32 fits 32 mm bodies only. Smaller planetary bodies take the D21 or D25; ASI6200 / ASI2400 / ASI2600 take the D60 No IR-cut option in this size. Carry a UV/IR-cut filter in a ZWO filter drawer or filter wheel instead No installation direction: ZWO confirms the window has no preferred orientation, so the coating works either way round Replacement procedure: see ZWO's official guide, How to Replace the Camera Protective Window Mechanical part only — no electronic function, no camera communication Important Limitations This window does not cut UV or IR, and ZWO does not make a D32 that does. On a one-shot-colour camera behind a refractor with nothing in the train, infrared will focus at a different point than visible light and soften the image. Put a UV/IR-cut filter in your train Not a threaded filter. It is a bare optical window that only works installed inside the camera body Replacement means opening the sensor chamber. Dust introduced during the swap lands on or near the sensor — work in still, clean air Fits 32 mm bodies only, and not the ASI585 Air. Check your camera against the list above before ordering Sold as a single window. No tools, gaskets, or retaining ring included Frequently Asked Questions Which cameras use the D32 AR window? The ASI1600, ASI294, ASI183, ASI533, ASI585, ASI990, and ASI991 series. The ASI585 Air is excluded. Is there a D32 UV IR-cut window? No. ZWO makes the D32 in AR only. If you need IR-cut on one of these cameras, use a UV/IR-cut filter in a filter drawer or wheel ahead of the camera. Why is this window 2 mm thick when the D21 and D25 are 1.1 mm? The larger clear aperture needs a thicker substrate to hold its figure. Keeping 1/4 λ flatness across 32 mm takes more glass than across 21 mm. Does the window have to face a particular direction? No. ZWO confirms there is no specific installation direction. My ASI1600 window is scratched — can I just leave it out? The camera will focus and operate without it, but the sensor chamber is then open to dust and humidity, which is a far worse problem than the scratch. Replace it. I have an ASI585 Air. Does this fit? No. ZWO excludes the ASI585 Air from the D32 match list even though other ASI585-series bodies are included. Check before ordering. Will this fit my ASI2600 or ASI6200? No. Those bodies use the 60 mm D60 window. This is 32 mm. Is this good for beginners? The part is simple; fitting it is not, since it means opening the sensor chamber. If you are not confident working clean, have it done rather than risk dust on the sensor. Bottom Line In short: a 32 mm × 2 mm anti-reflective window at 1/4 λ flatness — the only protective window ZWO makes for the ASI1600, ASI294, ASI183, ASI533 and ASI585 bodies. There is no IR-cut version in this diameter, so plan on a UV/IR-cut filter in your train if you shoot one-shot-colour.
