IDAS Light Pollution Suppression D1 Filter for ASI: This Light Pollution Suppression Filter is for ZWO ASI cameras with the M42 interface. (APS-C or smaller sensors (except for the 2600MC sensor).
In addition to blocking selected light pollution emission bands, IDAS filters block the range 700-1000 nm to insure that silicon sensors are adequately blocked from unwanted IR.
Plots shown are measured responses of production filters.
Light pollution suppression (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 the filter plot above to see the effect on light pollution emission bands).
Note: The most recently introduced version (D2) has a bandpass designed to cope with the increasing trend of society's switch to LED lighting.
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 +/-1 nm from the +/- 3 or 4 nm 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 as shown in CCD images (comparison testing by G. Tomita in Tokyo).
Additional independent tests and reviews are available here:
Note, however, that light pollution suppression filters are not a perfect substitute for dark skies.
- 1.1 mm thickness.
- The required t-thread male length : 3.9 mm to 4.3 mm.
- Fully made in Japan.
- Fits ASI M42-interface cameras (APS-C or smaller sensor except 2600MCPro).
- The set includes 2 spacer rings for the proper spacing adjustment.