IDAS LPS-V4 Nebula Filter
The IDAS LPS-V4 Nebula Filter is designed to provide maximum contrast between key astronomical emission lines and a light polluted sky. These filters incorporate IDAS MBT, UFP, and IGAD technologies to insure undegraded and extremely durable optical performance.
- Near IR is blocked completely, eliminating the need for an additional filter to block IR.
- Narrower H-alpha bandpass. In combination with a Kenko R1 filter, this can be used as a 19nm bandpass H-alpha filter.
- Retains the excellent color balance of the LPS-V3 filter when one-shot color cameras are used.
- Easy creation of H-alpha enhanced color images
Available in 1.25″, 52mm sizes as well as a clip filter for Canon EOS APS-C.
The IDAS LPS filters are designed to suppress the common mission lines generated by artificial lighting, yet allow the important nebula emission lines to pass, thus enhancing the contrast of astronomical objects, particularly emission nebulae (see filter plots to see the effect on light pollution emission bands). The most recently introduced version of LPS Filters (D2) has a bandpass designed to cope with the increasing trend of society’s switch to LED lighting.
Unlike other light pollution suppression filters, IDAS filters are specifically designed for balanced color transmission using the IDAS unique Multi-Bandpass Technology (MBT) process. The balanced transmission allows color photographs to be taken with minimal color cast to broadband emission objects such as stars, galaxies and globular clusters.
LPS filters utilize the unique IDAS Ion Gun Assisted Deposition (IGAD*) coating technology for superior coating durability (quartz hardness) and safer cleaning. IGAD coatings also improve temperature and humidity stability of the filter performance, reducing spectrum shifts down to +/-1nm from the +/-3 or 4nm shift of standard coatings.
CCD imaging can also benefit, because although CCD imagers can already shoot through light pollution to some extent, including an LPS filter to the setup gives an added (signal-to-noise) edge.
Note, however, that light pollution suppression filters are not a perfect substitute for dark skies.
In addition to blocking selected light pollution emission bands, IDAS filters block the range 700-1000nm to insure that silicon sensors are adequately blocked from unwanted IR.
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 technology originally developed for biomedical microscopes, but improved by IDAS by combining it 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.