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Astronomik OIII-CCD Filter

Astronomik OIII-CCD Filter
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Our Price:  £100.00(Inc. 20% VAT)
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Filter Size:  


Model:  AF220
Brand:  Astronomik

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The Astronomik OIII CCD filter is a narrow band emission-line-filter for CCD photography. The filter lets the light of double ionized Oxygen of emission nebulae pass and blocks nearly the whole remainder of the spectrum where the CCD is sensitive. 
The full width at half maximum (FWHM) of 12 nm is optimal suitable for common CCD cameras and allows the use of very fast optics The optimal aperture ratio for the use of the filter is 1:3 to 1:15 with apertures of more than 6" (150mm). It should be noted that the filter has a transmission of up to 99%, which cannot be attained by stacking more narrow-band filters. A further note, which led to selecting the half width (FWHM), is the dark current of common CCD imagers. Exposures with a CCD cooled to -15°C are limited by the dark current of the CCD, even in large cities with a bright background.

Another advantage of the 12 nm filter is the better availability of guiding stars for cameras with a built-in-autoguider (SBIG). If you use a very strong filter like our H-alpha 6nm filter you often won't find a usable guidestar.

Together with our other three Astronomik emission-line filters you can do great color images even from very light polluted places!
Main use
The Astronomik OIII CCD increases the contrast between objects, in this case between the OIII emission line and the skyglow background. Our Astronomik OIII CCD completely suppresses the emission lines of artificial lighting (mercury (Hg) and sodium (Na)) and skyglow. Transmission losses and chromatic distortions, which arise with other filters, only occur with Astronomik filters when extremely bright aperture ratios of 1:2 and more come into play. The filter has a built-in IR-blocker up to 1150nm. You don't need an additional IR-blocker with this filter.
Other uses
When using the Astronomik OIII CCD filter togther with the H-alpha, OIII CCD and the SII CCD filters you can obtain three-color images of emission line objects (gas nebulae) from locations with very strong light pollution. To do so, you would take an image in three different wavelengths, select each one as a color-channel in Photoshop and paste them together as one single color image.
If you plan to create color images from emission line data, our CLS CCD filter is a great choice for the Luminance channel
The OIII CCD is also great for visual observation. If you plan to get filters for visual observation and for astrophotography get the CCD filter: You may use this filter visual as well as in front of you camera. The built-in IR-blocker doesn't disturb visual observation but you need an additional IR-blocker if you want to use the visual filter with your camera.
Suitability

  • Visual observation (dark skies): Verry good, huge contrast enhancement at O III-emission nebulas
  • Visual observation (urban skies): Verry good, huge contrast enhancement at O III-emission nebulas
  • Film photography: It depends, very long exposure time
  • CCD photography: Verry good, huge contrast enhancement at O III-emission nebulas
  • DSLR photography (original): Verry good, huge contrast enhancement at O III-emission nebulas
  • DSLR photography (astro modified): Verry good, huge contrast enhancement at O III-emission nebulas
  • DSLR photography (MC modified): Verry good, huge contrast enhancement at O III-emission nebulas
  • Webcam / Video (Planets): Unsuitable
  • Webcam / Video (Deep Sky): Reasonable, if light pollution is a big problem and OIII Objects are beeing observed
Technical Data
  • Parfocal with other Astronomik filters
  • Glass thickness: 1mm
  • Completely resistant against high humidity, scratches and aging effects
  • Diffraction limited, the filter will not reduce the optical performance of your telescope!
  • Astronomik filters are delivered in a high-quality, long lasting, filter box
  • The filter is available in the following sizes
  • Mounted filter in 1,25" cell (M28,5mm x 0,5mm)
  • Mounted filter in 2" cell (M48,5mm x 0,75mm)
  • Mounted filter in T2 cell (M42mm x 0,75mm)
  • Mounted filter in SC cell (2" x 24Tpi)
  • Mounted filter in EOS-Clip cell
  • Unmounted filter with 38mm diameter
  • Unmounted filter with 50mm diameter
  • Unmounted filter 50mm x 50mm square
  • Filters with custom diameters are available upon request

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