Astronomik Filters 1.25" SII CCD filter

Astronomik SII 12nm Filter

Crafted specifically for CCD photography, the Astronomik SII-CCD filter is a narrow-band filter tailored to allow the passage of ionized sulfur (SII) light while effectively blocking the majority of the visual spectrum as well as infrared, which can affect CCD sensitivity.

Since the conclusion of 2008, we've overhauled all our photographic filters, now introducing our new "Halo-Free" filters.

Featuring a Full Width at Half Maximum (FWHM) of 12nm, this filter is optimally suited for common CCD cameras and supports the utilization of fast optics, with an application range extending from f/2.8 to f/15. Transmission losses and chromatic distortions, observed with other filters, typically only occur with Astronomik filters under extremely bright aperture ratios of f/2 and beyond. It's worth noting that this filter boasts a transmission rate of up to 99%.

One notable advantage of the 12nm filter is the ample availability of guiding stars for cameras equipped with built-in autoguiders (e.g., SBIG). This is particularly beneficial compared to stronger filters like our 6nm version, where finding a usable guidestar can be challenging.

The Astronomik SII CCD filter significantly enhances contrast between objects, particularly those featuring SII emission lines and the skyglow background. It effectively suppresses emission lines from artificial lighting (such as mercury and sodium) and skyglow.

Main Use:

The Astronomik SII CCD filter enhances contrast between objects, emphasizing the SII emission line against the skyglow background. It also effectively suppresses emission lines from artificial lighting (mercury and sodium) and skyglow. Thanks to the high optical quality of the Astronomik H-alpha-CCD substrate, you'll experience the same crisp, sharp stars as you would with your regular telescope.

Unlike purely visual filters, photographic CCD filters feature built-in IR-blocking, mitigating optical issues caused by infrared radiation.

Specifications:

Capacity: Filters

Connection (to the telescope): 1.25"

Coating of Optical System: Multiple

Mount Material: Aluminum

Frame: 1.25"

Series: SII CCD

Type of Build: Line Filter

Area of Application: Visually Not Useful, Useful for Photographs, Anti Light-Pollution