Triband RGB Ultra Filter II - 2'' Mounted

The Antlia Triband RGB Ultra Filter II (2" mounted) is a multiband imaging filter designed to improve contrast on emission nebulae while retaining the ability to image broadband targets. Antlia added an H‑Beta (486.1 nm) passband to their Triband RGB design to better capture blue emission features alongside H‑alpha and O‑III transmission.

Key imaging notes

• Targets: Intended for emission nebulae and a broad range of deep‑sky objects including galaxies, reflection nebulae and star clusters.
• Camera compatibility: Described for use with both one‑shot‑colour (OSC) and monochrome camera systems.
• Fast optics: The passband design is stated to perform with fast optical systems down to approximately f/2.
• Colour balance: Engineered for balanced RGB transmission to minimise colour cast on broadband objects.

Optical performance

• Peak transmission is reported above 92% at the main emission lines used (H‑alpha, NII, SII, O‑III and H‑Beta).
• Blocking is specified as ≥OD4 across 300–1050 nm.
• Filter glass thickness is given as 2.00 mm ±0.05 mm.

These points are summarised from the manufacturer. If you need measured transmission curves for your specific camera and telescope configuration, consult Antlia's published spectrum curves or contact us for further testing resources.