ZWO ASI533MM Pro Cooled Mono Astronomy Camera

A square-format mono camera that makes narrowband imaging affordable

The ZWO ASI533MM Pro is a cooled monochrome astronomy camera built on Sony's back-illuminated 9MP IMX533 sensor. It's a good first mono camera for someone who has learned the basics with a color camera and wants to try narrowband or LRGB imaging without the cost of a large sensor and 2-inch filters. ZWO describes it as the successor to the ASI183MM Pro, keeping the high sensitivity and adding zero amp glow, larger 3.76µm pixels and two-stage TEC cooling. The body is 78mm across and weighs 470g (1.0lb).

Key specs: Sony IMX533 mono sensor, 1" square (11.31 × 11.31mm) · 9MP (3008 × 3008) · 3.76µm pixels · 91% peak QE · 14-bit ADC · read noise 1.0–3.8e⁻ · 50,000e⁻ full well · cooling to 35°C below ambient · zero amp glow · USB 3.0 · 470g

What you can image

• Emission nebulae in narrowband: the Rosette, Eagle, Crescent, Pacman, Bubble and Soul Nebulae, and the Elephant's Trunk in IC 1396, in hydrogen-alpha, OIII and SII for false-color "Hubble palette" images.
• Galaxies in LRGB: the Whirlpool, Pinwheel, Sunflower and Triangulum Galaxies, M81 and M82, and the Leo Triplet. On the 490mm ZWO FF70 the field is about 1.3° × 1.3° at 1.6″ per pixel; on the 770mm FF110 it's about 0.84° × 0.84° at 1.0″ per pixel.
• Wider fields: on a 250mm RedCat 51 the field grows to about 2.6° × 2.6°, enough for the core of the Heart Nebula, the Pleiades or the Orion Nebula with the Running Man.
• Planetary nebulae: the Ring, Dumbbell, Helix and Owl Nebulae respond especially well to hydrogen-alpha and OIII filters.

How it works

A mono camera records every pixel at full sensitivity and leaves color to filters. A filter wheel in front of the camera switches between filters during the night, and software combines each filter's frames into a color image: luminance plus red, green and blue for natural color, or hydrogen-alpha, OIII and SII for narrowband. The camera connects to a computer or an ASIAIR Plus over USB 3.0 and runs its cooler from 12V (ZWO recommends 12V at 3–5A, 5.5 × 2.1mm plug, center positive). Two USB 2.0 ports on the back power and control the filter wheel and a guide camera right at the scope.

The sensor sits 17.5mm behind the camera face, including an 11mm T2 ring. Without a filter wheel, the included 21mm and 16.5mm extenders and M42-M48 adapter bring the total to the standard 55mm used by most flatteners and reducers. With a ZWO filter wheel, you remove the 11mm ring, mount the wheel directly to the camera, and move the ring and extender to the telescope side, as shown in ZWO's connection diagram below.

Using it in Colorado

• Front Range skies: narrowband filters cut through city light, so you can shoot nebulae from Denver on any clear night, and save LRGB galaxies for darker sites like Jackson Lake State Park or the Westcliffe area.
• Moonlit nights: hydrogen-alpha in particular is barely affected by the Moon, which turns nights most color imagers lose into productive ones.
• Big temperature swings: the cooler holds a set temperature as the night cools off, so your darks stay matched. ZWO doesn't recommend running the camera below −20°C ambient.

What to add for the best results

• A filter wheel (required for color): the ZWO EFW 5x1.25" (2025) holds LRGB plus one narrowband filter, and the EFW 8x1.25" (2025) holds a full LRGB and SHO set with a spare slot. Both are 20mm thick and plug into the camera's USB hub. If you might move up to a larger sensor later, the EFW 7x36mm (2025) also works.
• Filters (required for color): the ZWO 7nm SHO narrowband set in 1.25", and the ZWO LRGB set in 1.25" or the Optolong LRGB + SHO 7nm 7-piece set. The 16mm sensor diagonal is small enough that 1.25-inch filters in a wheel next to the camera don't vignette, so there's no need to pay for 2-inch filters.
• 12V power (required for cooling): the ZWO 12V 5A adapter at home, or a PowerTank Lithium Pro in the field.
• ASIAIR Plus: runs the camera, filter wheel, mount, guiding and focuser from your phone, including multi-filter sequences.
• ASI220MM Mini: a sensitive guide camera for a guide scope or the ZWO OAG.
• ZWO EAFN electronic focuser: refocuses automatically after filter changes and as the temperature drops.
• A telescope and mount: the ZWO FF70 + AM3N bundle is a well-matched, portable setup for this camera.

ASI533MM Pro vs. ASI533MC Pro vs. ASI2600MM Pro

See all ZWO cooled deep-sky cameras.

What's in the box

• ASI533MM Pro camera and camera bag
• 1.25" nosepiece and T2-1.25" adapter
• USB 3.0 cable (2m) and two USB 2.0 cables (0.5m)
• T2-M48 extender (16.5mm), T2 extender (21mm) and M42-M48 adapter
• Four thin spacers (0.5mm, 2 × 0.2mm, 0.1mm) and a cover
• Quick guide

The 12V power supply, filter wheel, filters and guide camera are sold separately.

ZWO ASI533MM Pro FAQ

Is the ASI533MM Pro good for beginners?

It's a good first mono camera, and many people buy it as their second camera after a color one. Mono adds a filter wheel, filters and more processing, but the small sensor keeps the cost of those down and is forgiving of flattener spacing and tilt. If this is your very first dedicated astro camera, the ASI533MC Pro is simpler.

Mono (MM) or color (MC)?

The MC gives color images in one shot. The MM needs a filter wheel and filters but collects more signal per pixel, gives sharper detail and is the better choice for narrowband imaging from light-polluted skies.

ASI533MM Pro or ASI2600MM Pro?

Both have 3.76µm pixels, so detail per pixel is the same on the same telescope. The ASI2600MM Pro covers about 2.9 times the sky area and has a 16-bit ADC, but needs 36mm or 2-inch filters and a telescope that covers APS-C. The ASI533MM Pro costs about half as much and works with 1.25-inch filters.

Which filters and filter wheel do I need?

1.25-inch mounted filters (or 31mm unmounted) in a 1.25-inch wheel. A common set is luminance, red, green and blue plus hydrogen-alpha, OIII and SII, which fits the 8-position EFW with a slot to spare. Many owners start with a hydrogen-alpha filter alone and add the rest over time.

What telescope works with it?

Almost any imaging telescope with a flattener or reducer set for 55mm back focus. Its 16mm diagonal is covered easily by small refractors like the RedCat 51 and the ZWO FF series.

Can I image planets with it?

It can, but a small, fast planetary camera does better on planets. The ASI533MM Pro is built for long deep-sky exposures.

Specifications