The IDAS HEUIB-II (H-α Enhanced UV IR Blocking) filter is designed for enhanced spectrum DSLRs and one-shot color CCD astronomical cameras.
Besides removing the IR and UV ends of the spectrum which are often out of focus in refractive optics, it isolates the common H-alpha line relative to the surrounding extreme red end of the spectrum, making it easy to bring out the faint H-alpha emission nebulosity of astronomical photos, yet retain the background color balance of broadband photos.
Some comparison shots taken with the enhanced Canon 6DH (standard Canon UV/IR blocking filter vs. HEUIB-II filter) show a clear difference both in background sky color balance and contrast of H-alpha nebulosity in the extremely faint object IC1396. Note the good background color balance as shown in the histograms of the individual color channels of the HEUIB-II filtered image.
IDAS Filter Technology
A chain is only as good as its weakest link. This applies as well to an optical system such as a telescope/filter/imager system. With this in mind, IDAS filters are manufactured using unique technologies that result in quality that meets or exceeds that of the rest of your optical imaging system:
IGAD (Ion-Gun Assist Deposition)
This coating technology was originally developed for the optical communications field where long-term stability (>25 years) over harsh field conditions is required. IDAS is the first manufacturer to apply this technology to astronomical filters. This results in superior filters with robust coatings and long-term spectral stability even under temperature and humidity extremes. This stability is especially important for bandpass curves with steep slopes such as H-alpha, LPS filters, and other narrow bandpass filters. IGAD filters virtually eliminate bandpass shifts from the +/-3 or 4nm typical of standard coating filters.
MBT (Multi Band-pass Technology)
This is a technology originally developed for biomedical microscopes but improved by IDAS by combining it with the IGAD hard-coating technology described above. The excellent filter responses possible with this technology allows IDAS to create very complicated filters for astronomical use such as the unique LPS filter.
UFP (Ultra Fine Polish) Finishing
IDAS filters are polished twice as long as is typical for optical glass. In combination with the use of high-quality substrate glass, no scratches, bubbles, or other defects are visible even under microscopic inspection.