ALP-T Dual Band 5nm Ha&OIII Filter 2” Mounted

The Antlia ALP-T Dual Band 5nm Ha & OIII filter is a 2" mounted dual line-pass filter developed for one-shot colour (OSC) astrophotography. It passes the hydrogen-alpha (Ha) and doubly ionised oxygen (OIII) emission lines while strongly suppressing out-of-band light to improve contrast on emission nebulae.

Key design and performance points

This filter features advanced multi-layer coatings on a double-sided polished substrate. It is engineered to deliver steep bandpass edges, a flat-top transmission profile across the passbands, and near-infrared blocking to 1100 nm. Antlia states out-of-band suppression to an optical density of approximately OD4.5.

Intended use

• Optimised for DSLR and colour CMOS/CCD cameras (one-shot colour).
• Can be used with monochrome cameras for narrowband imaging workflows to reduce required exposure time.

Mount and mechanical details

• 2" filter cell (M48 x 0.75 thread).
• Ultra-thin filter cell to maximise clear aperture and reduce vignetting.
• Black anodised finish with laser engraving.

Warnings and limitations

• Not for solar imaging. Do not use to observe the Sun; serious eye damage will result.
• Not intended for unaided visual night observing.

Note: Additional independent tests and sample images are referenced by the manufacturer. Photographer credits were provided alongside sample images.