Focus Scientific

Baader LRGBC CCD Filter Set (1.25\")

The Baader premium-grade 1.25" LRGBC filter set is perfect for smaller sensor monochrome CCD cameras. It works well in fast optical systems from f/10 to f/2.8.

With a monochrome (black and white) camera, it is necessary to image through multiple filters to get a colour image. This is how the best astroimages are produced because no resolution is lost to a bayer matrix, as found in a one-shot colour camera.

The colour filters have been optimized by Baader for astrophotography, using the best in thin film technology. The Oxygen-III line is passed by both the green and blue filters, preserving its natural blueish-green appearance. The Hydrogen-Beta line is passed only by the blue filter, ensuring it is properly represented by its natural blue appearance. The bandgap between the red and green filters has been placed at the Mercury/Sodium lines, blocking the light pollution that dominates that part of the spectrum.

Shooting a fourth image through a luminance filter can greatly improve an astrophotograph by allowing every pixel on the camera to use the entire visible spectrum. The resulting image will contain much more signal than the colour components alone, and can be used to enhance the final image. The luminance filter only blocks the Ultraviolet (UV), and Infrared (IR) wavelengths. This prevents halos and reflections, essential with refracting optics

The luminance filter is also useful in protecting valuable Hydrogen Alpha filters from heat stress and damaging IR.

A parfocal clear filter greatly simplifies the task of focusing. It passes the entire electromagnetic-spectrum, providing the camera with the maximum amount of light possible for focusing. As it is parfocal with Baader's other filters, refocusing is not necessary on the more restrictive imaging filters.

Baader LRGB filters feature extremely sharp cutoffs. This allows the important H-alpha and S-II deep red lines to be fully included in the red and luminance filters, while excluding unwanted IR light. In addition, sharp cutoffs below 420nm eliminate violet halos around bright stars; more effective than simpler so-called Minus Violet photographic filters.

The glass substrate is finely optically polished plane parallel, providing 1/4 wavefront over entire surface.

Multi-layer dielectric coatings are plasma-assisted and ion beam-hardened using the latest technology. The Baader Planetarium LRGB Filter coatings will never degrade from normal use or normal cleaning.

Unmatched 98% Average Transmission. Freedom from ghost images. Very low reflection multi-coating, Striae-free, and plane-parallel substrate.

Specifications

  • Parfocal, no need to refocus when switching filters
  • Full visible spectrum, red, green, and blue filters
  • Clear and parfocal focusing filter
  • Sharp cutoffs above 680nm and below 420nm
  • Rejection of unwanted Mercury/Sodium line in the red and green filters
  • 28.5mm filter threaded
  • Dielectrically coated
  • 1/4 wavefront surface accuracy
  • Made in Germany