Antlia M48 Adapter with H-alpha 3 nm Pro Filter for Canon EF/EF-S cameras (Antlia) connects a camera with a Canon EF or EF-S mount to an M48 × 0.75 interface, allowing it to be attached to a suitably terminated astrophotography imaging train. The integrated narrowband filter transmits hydrogen Hα emission at a wavelength of 656.3 nm while strongly suppressing light outside the transmission band. The manufacturer specifies a back focus of 55 mm.

Key features

• combination of a Canon EF/EF-S camera adapter and H-alpha 3 nm Pro filter in one component
• M48 × 0.75 interface designed for use with a suitably terminated astrophotography imaging train
• back focus of 55 mm
• narrow transmission band with a 3 nm FWHM, centred on the hydrogen Hα line
• transmission in the Hα band exceeding 88%
• out-of-band blocking exceeding OD5
• improved contrast of emission-nebula structures and reduced background brightness
• suitable for imaging from light-polluted areas and when the Moon is present
• transmission characteristics designed for use with optical systems as fast as f/3
• steep band profile reducing halo formation around bright stars

Set contents

• Antlia M48 adapter for Canon EF/EF-S cameras with integrated H-alpha 3 nm Pro Filter

Technical specifications

• product type: camera adapter with integrated narrowband filter
• manufacturer variant: M48-H-alpha Adapter
• camera mount: Canon EF/EF-S
• imaging-train interface: M48 × 0.75
• back focus: 55 mm
• filter type: H-alpha 3 nm Pro
• transmitted emission line: Hα
• central wavelength: 656.3 nm
• FWHM bandwidth: 3 nm
• central-band transmission: over 88%
• out-of-band blocking: over OD5 across the 300–1000 nm range
• compatible optical-system focal ratio: down to f/3
• application: astrophotography of objects emitting Hα radiation
• example targets: emission nebulae, planetary nebulae, Wolf-Rayet objects and supernova remnants
• suitable for night-time visual observation: not recommended
• suitable for solar imaging: no

The Antlia adapter allows a Canon EF or EF-S camera to be connected to an M48 astrophotography imaging train while isolating the narrowband Hα signal without requiring a separate filter holder.