Chroma 5nm SII Narrowband Filter

£459.00✓ 2 year warranty

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1.25": £459.00
2": £975.00
31mm Round Unmounted: £459.00
36mm Round Unmounted: £620.00
50mm Round Unmounted: £925.00
50mm Square Unmounted: £1,379.00

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About this product

Model: chroma_sii_5nm_125
Part Number: CT-27010-1.25M

Premium quality 5nm SII Narrowband Filter

Chroma SII filters isolate the spectral emission of singly ionised sulfur atoms, also common in nebulae. Emission is at two lines occurring as a doublet, at 671.6 and 673.1 nm. This filter also separates sulfur emission from H-alpha emission (656.3nm).

Chroma Technology is an employee-owned company based in Vermont, USA. Chroma manufacture the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximise transmission. Chroma astronomical filters are used worldwide in research and amateur applications.

Highly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

All filters may be used with focal ratios of f/4 or slower. For optics faster than f/4 then due to the spectral shift we recommend using the 5nm filters instead.

FEATURES

CWL: 672.4nm, Bandwidth: 5nm
Durable sputter coatings
Parallelism: <30 arcsec
Thickness: 3.0 +/-0.05mm
Filters designed for use with CCD and for f/4.0 or slower
Transmitted wavefront better than 0.25 waves/inch
No reflections leading to image distortions or ‘back reflections’

Transmission Chart

Cleaning and Handling

Handle coated pieces by the edges only. Clean gently only if necessary. Loose particles should be removed with a bulb puffer or filtered, pressurised air cleaner. If necessary, gently wipe surface using anhydrous alcohol and lint-free lab towels. Use new surface of towel with each wipe.

AVOID TOUCHING OR WIPING A/R COATED OR METAL MIRROR SURFACES
AVOID HANDLING EXPOSED COATINGS WITH BARE FINGERS

Orientation Instructions

Proper orientation of the filter is necessary in order to minimise autofluorescence and maximise performance. There is a caret (arrow) located on the edge of each filter in order to aid orientation. Excitation (x) filters should be positioned with the arrow pointing toward the specimen, toward the inside of the cube, and away from the light source. Emission (m) filters should be placed with the arrow pointing toward the specimen, toward the inside of the cube, and away from the detector/eye. Dichroic mirrors should be mounted with the coated surface toward the light source, excitation filters, and the specimen. The dichroics either have an arrow on the side pointing to the coated side, or they are beveled on the coated side. The beveled side is the smaller surface.