Antlia ALP-T 5 nm H-alpha/OIII Filter
Select the 2-inch mounted format. Check the mount, focal ratio, and height of the filter mount.
Price range: CHF 275.35 through CHF 351.12
Cooled color astronomical camera for deep-sky imaging.
CHF 773.10incl. Swiss VAT
Part Number ZWO-A136684
Will be ordered for you
Timeframe: 10 days to 3 weeks
Estimated shipping: Between November 22 and 27, 2026
Cooled color astronomical camera for deep-sky imaging.
The color version allows colors to be captured within a single sequence, without the sequence of RGB filters required by a monochrome camera. The choice of an additional filter depends on the target, the optics, and the model’s protective window. Active cooling helps stabilize long exposures and calibration. A compatible external power supply is required; the USB connection does not replace the power supply for the cooled module. Choose an operating temperature that the system can maintain throughout the entire session. Before mounting, check the thread, the distance between the sensor and the adapter, and the space occupied by the filters or the optical splitter. The sensor alone does not determine the final field of view: the instrument, the focal length, and any reducers also play a role. Take your calibration images using settings consistent with those used for observations. An astronomical camera provides no protection for solar observation: any use on the Sun requires a filter specifically designed for the instrument and installed correctly.
Documentation and Compatibility: ZWO official data sheet.
Official illustration common to all variants in this product line. The part number and specifications listed on this sheet identify the version being sold.
The ZWO ASI294MC Pro is designed for deep-sky photography using long exposures: nebulae, galaxies, and clusters. Its cooling system (30 °C below ambient temperature) keeps thermal noise very low during exposures lasting several minutes. With its 4.63 µm pixels, it works well with instruments having focal lengths of approximately 500 to 950 mm (1 to 2″ per pixel). In color, a single series of exposures produces the image; with a double-band filter, it is capable of imaging emission nebulae even under light-polluted skies.
The Sony IMX294 features a 4/3″ (19.2 × 13 mm) sensor with large 4.63 µm pixels and a well capacity of 63.7 ke⁻: plenty of signal per pixel and a wide field of view, all at a lower price than APS-C cameras.
The cooling system requires an external 12 V DC power supply; 3 A is recommended (5.5 × 2.1 mm connector, center positive). It is not included with the camera: we recommend the'Pegasus Astro 12 V 10 A power supply (2.1 mm plug). In the field, a Pegasus Astro unit like the Pocket Powerbox Advance It also powers the mount and the heating elements from a single source. Without a 12-volt power supply, the camera operates via the USB cable, but without cooling.
The camera's back focus is 17.5 mm (6.5 mm without the removable 11 mm T2 extension ring). Mount: M42 × 0.75. If using a corrector or reducer that requires 55 mm, make up the difference with extension rings, taking into account the filter wheel or filter drawer, if present.
We recommend the Antlia ALP-T 5 nm Hα/OIII filter : This dual-band filter isolates the Hα and OIII lines from emission nebulae and significantly reduces light pollution. It is available in a 2″ mounted version (for a filter drawer or a threaded adapter) and in a 36 mm unmounted version with a holder. For galaxies, reflection nebulae, and clusters, the Antlia Quad Band filter reduces light pollution while transmitting the Hα, Hβ, OIII, SII, and NII lines.
With a ZWO OAG Optical Splitter and a small guidance camera like the ZWO ASI220MM Mini, you guide through the main telescope. A guide scope such as the'Askar 32 mm is the simplest alternative.
An anti-fog heating element is built into the front of the sensor window. It prevents fogging and frost when the sensor is cooled well below room temperature.
Yes: A built-in USB 2.0 hub allows you to connect a filter wheel, a guide camera, or a focuser directly to the camera, reducing the number of cables running to the computer.
The color version is the simplest: a single exposure produces the color image. The monochrome version, the ZWO ASI294MM Pro, requires a filter wheel and a longer exposure time. In return, it is more sensitive and produces better results in narrowband imaging.
The manufacturer's manual (in English) is available here: ZWO ASI294MC Pro Manual (PDF).
Here are a few accessories we've selected for this model, depending on your needs.
Select the 2-inch mounted format. Check the mount, focal ratio, and height of the filter mount.
2-inch filter mounted. Check to make sure you have the version that matches the focal ratio and the height of the mount.
Optional 7 × 2-inch wheel. Check the height of the filter mounts, the connections, and the draft.
The ZWO setup shown here, which includes a 2-inch wheel, requires a 5-mm M42 tilt plate (sold separately) and a 1-mm M42 spacer. Check the parts you receive, the connections, the focus, and the prism; guide camera sold separately.
ZWO 12 V / 5 A power supply—optional if you don't already have a suitable power source. Check the connector, polarity, and the power requirements for your setup.
Optional classic ZWO splitter, an alternative to the OAG-L. The manufacturer’s diagram for a color camera without a wheel uses the 21-mm M42 extension tube and the 11-mm camera ring; check the parts you receive, the focus, and the prism. Guide camera sold separately.
