Astronomik Filters OIII 12nm CCD SC (43812)

Narrowband filters represent a significant advancement in performance and durability for imaging and research purposes. These filters enhance the contrast of emission targets by reducing background signals, ensuring a guaranteed transmittance of over 90% at the emission wavelength. This high transmittance provides the strongest possible signal for astrophotography. Additionally, narrowband filters are designed to minimize halos around bright stars, even during long exposures of 30-45 minutes, which are common in narrowband imaging. They are coated to the edge and edge-blackened to reduce stray light effectively, crucial for blocking most light except within the narrow bandpass.

The primary purpose of narrowband filters in imaging is to improve contrast. By reducing the background signal, these filters make faint features more visible. The narrower the filter, the greater the contrast enhancement. However, maintaining a high signal at the emission line (%T) becomes challenging as filters become spectrally narrower. This is why the >90%T guarantee is essential, even though achieving it is costly. It ensures that users can benefit from improved contrast compared to more affordable 7-8.5 nm filters available on the market. For example, images of the Crescent Nebula (NGC 6888) taken with increasingly narrow filters show how the nebula and its faint surrounding nebulosity become more pronounced against the background. Recent production technologies have even increased transmittance to 97-98%T at emission wavelengths, surpassing legacy specifications.

Specifications

• Capacity:
  • Mount Material: Aluminium
  • Transmission: 95%
• Optical System Coating: MRF
• Frame: SC thread
• Half-value Width (nm): 12
• General Features:
  • Series: OIII 12nm
  • Type: Line filter
• Area of Application:
  • Useful for photographs: Yes
  • Galaxies and star clusters: Yes
  • Anti light-pollution: Yes
  • Planetary nebulae: Yes
  • Supernova remains: Yes
  • Hydrogen nebulae: Yes