Astronomik UHC 36 mm, with protective ring (Astronomik, SKU: 10210536) is a nebula filter that passes the principal hydrogen and oxygen emission lines while suppressing background light. It helps reveal structure in emission and planetary nebulae by selecting wavelengths rather than increasing the brightness of the object itself.
When imaging with an infrared-sensitive camera, an additional IR-blocking filter may be needed if this function is not already provided by the camera. This filter does not have the response of a version with additional infrared blocking.
• transmission of H-beta, OIII and H-alpha emission lines
• selective suppression of light outside the useful nebular bands
• suitable for observing and photographing nebulae
• ring protects the glass edge during installation in a filter wheel
• durable coatings resistant to scratches and moisture
• filter, Astronomik UHC 36 mm, with protective ring
• protective filter box
• manufacturer: Astronomik
• manufacturer SKU: 10210536
• type: UHC nebula filter
• transmission range: 480–505 nm and above 645 nm
• main passband width (FWHM): 25 nm
• typical transmission at 486, 496, 501 and 656 nm: 95%
• recommended focal-ratio range: f/3–f/15
• shape: round
• nominal size: 36 mm
• construction: protective ring, without a screw thread
• mechanical thickness including ring: 3 mm
• glass thickness: 1 mm
• parfocality: with standard Astronomik filters using 1 mm glass
• country of manufacture: Germany
Selective transmission helps separate the nebular signal from the sky background.
