Filter Celestron anti-light pollution filter for Rowe-Ackermann Schmidt (RASA) 8" astrographs
Light pollution in the night sky can significantly degrade the contrast in astronomical images. This is especially true when using very fast telescopes such as the RASA 8", because the sky background saturates very quickly. Light pollution noise dilutes the signal from the celestial object you are photographing, making it difficult to obtain the most detailed image. The light pollution imaging filter for the 8" RASA solves this by blocking light pollution while transmitting light from deep sky objects. The result is bright, detailed objects emerging from the black sky background with superior contrast.
Fortunately, many light pollution sources have relatively discrete emission spectra; they emit light primarily at specific wavelengths. By strategically blocking these wavelengths, the filter greatly reduces the effects of light pollution without degrading overall image quality.
The Light Pollution Imaging (LPI) filter for the 8" RASA blocks light from some of the most common sources of light pollution between 400-700 nm (i.e., the visible spectrum), including high and low pressure sodium vapor streetlights, mercury vapor, and natural glow caused by oxygen in the atmosphere. Unlike some light pollution filters, the LPI filter blocks only specific areas of the spectrum rather than broad regions. This helps maintain image brightness and color balance. In addition, specific wavelengths associated with emission nebulae, such as H-α (656nm), H-β (486nm), OIII (496nm and 501nm), and SII (672nm), are highly transmitted, ensuring minimal loss of image brightness for those objects
The filter fits directly into the internal filter holder in the front lens cell of the RASA 8, where the optical window is normally mounted. By removing the clear window and replacing it with the filter, the optical performance of the entire system is maintained.
Each filter comes with a plastic case to safely store the filter or the placeholder glass that comes with your RASA when not in use. You will also receive a unique spectral transmission graph for your specific unit, allowing you to verify its performance.
- Optically flat, defect-free surfaces constructed of Schott glass with anti-reflective coatings.
- Material: Schott B270
- Glass Thickness: 1.9mm
- Filter diameter: 46 mm
- Clear aperture: 43 mm
- Coatings: Dichroic, multi-layer anti-reflective
- Aluminum cell, black anodized to fit the integrated filter holder on the 8" RASA, maintaining maximum optical performance.
Filter Celestron anti-light pollution for Rowe-Ackermann Schmidt Astrographs (RASA) 8"
