Askar OIII 7nm Narrowband Imaging Filter - 2"

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Askar OIII 7nm Narrowband Imaging Filter - 2"

The Askar OIII 7nm filter is suitable for imaging of OIII emitting nebulae or some supernova remnants. The Askar OIII filter has an extreme high transmission at a center wavelength of 500.7nm. The 7nm narrow bandwidth enables this astroimaging filter to block all the light pollution and other unwanted artificial lights or night glow. So the Askar OIII filter is an ideal instrument for astro-imaging in heavily light-pollution hit locations and delivers enhanced contrast at darker places.

The Askar OIII filter is designed for improving the contrast and details of some nebulae and supernova remnants. It works well on those nebulae emitting OIII. Featuring 7nm narrow bandwidth and a greatly high transmission at a center wavelength of 500.7nm, the Askar OIII filter can bring out the most amount of details of the emission nebulae, planetary nebulae and supernova remnants. Also, the out-of-band blocking ability is rated with OD4 (0.01%) with the blocking range of 200-1050nm. It delivers an excellent signal-to-noise ratio and a sharp cut-off rate to attenuate the disturbance from other wavelengths.

The narrow bandwidth and an effective cut-off rate are important indices when choosing a narrowband filter. The Askar OIII filter has a narrow bandwidth of 7nm and an extreme transmission of 90% at the peak, in the meanwhile, sufficiently suppressing other off-band wavelength. That’s why we sometimes call those 7nm-bandwidth, or even a smaller bandwidth of 3nm, a line filter. So the Askar OIII filter can efficiently reject all the light pollution. You can expect a terrific performance of this OIII filter in artificially-brighten background sky.

The production process is strictly controlled and every single Askar O III narrowband filter is individually examined and tested to ensure that they can highly satisfy the observing interests and needs of our customers.

Application

  • Narrow 7nm bandwidth, properly designed for astrophotography both in light polluted or dark locations.
  • Useful for imaging OIII emitting nebulae, planetary nebulae and supernova remnants.
  • High transmission of 90-95% and sharp cut-off can greatly enhance the contrast and bring out the most detailed information for those deep-sky objects.
  • Designed to sharply cut off the inference of artificial light from sodium vapor or mercury vapor street lights and other unwanted disturbance like sky glow.
  • The Askar OIII narrowband filter is not suitable for visual observation and not designed for imaging or observing the sun or other non-OIII-emitting objects.

ATTENTION! DO NOT USE THIS FILTER FOR OBSERVING THE SUN! SEVERE EYE DAMAGE MAY RESULT.

Images are for demonstration purposes only. Might show a similar product or the same product, but different size.

Askar OIII Narrowband (7nm) Filter Specifications

OIII 2"

Filter shape

round and mounted in cell

Size

2"

Surface quality

60/40

Thickness

1.85mm

Parallelism

30 arcsec

Angle of incidence

0 degree

FWHM (full width at half maximum)

7±1nm

CWL (central wavelength)

500.7±1nm

Transmission

>90% at 500.7nm

Optical density

OD4(0.01%) @ 200-1050nm

Filter threads

M48×0.75

Filter cell

black anodized matte

As authorised dealers for all our products they come with a full manufacturers warranty along with our satisfaction guaranteed, no-questions-asked full refund policy for a full 30 days.

Please see our returns policy for full details.

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