Astronomik OIII visual SC Rear Cell (2" / 24TPI) (SKU: 10211050 / 8h00bk)

Astronomik OIII visual SC Rear Cell 2" / 24 TPI (Astronomik, SKU: 10211050) is a visual filter for nebulae emitting in the doubly ionized oxygen lines. Its narrow passband transmits both principal OIII lines, helping reveal structure in planetary nebulae, supernova remnants and other emission objects.

Key features

• transmission of both principal OIII emission lines
• strong suppression of light outside the oxygen passband
• primarily intended for visual observation
• mounts on a telescope rear port with a 2" / 24 TPI SC thread
• durable coatings resistant to scratches and moisture

Included items

• filter, Astronomik OIII visual SC Rear Cell 2" / 24 TPI
• protective filter box

Technical specifications

• manufacturer: Astronomik
• manufacturer SKU: 10211050
• type: OIII visual-observation filter
• transmission range: 494–506 nm
• passband width (FWHM): 12 nm
• typical transmission at 496 and 501 nm: 95%
• recommended aperture for visual observation: approximately 150 mm or larger
• recommended focal-ratio range: f/3.5–f/15
• mount: rear SC / SCT connection
• thread: 2" / 24 TPI, nominal diameter 50.8 mm
• glass thickness: 1 mm
• parfocality: with standard Astronomik filters using 1 mm glass
• country of manufacture: Germany

Isolating the OIII passband helps reveal faint nebular structures against the sky.