Description
Light pollution suppression (LPS) filters are designed to suppress the common emission lines generated by artificial lighting, yet allow the important nebula emission lines to pass, thus enhancing the contrast of astronomical objects, particularly emission nebulae.
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. The comparison photos at right demonstrate (qualitatively) that the IDAS filter maintains better color balance than other filters which have been designed for visual use.
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. Refer to Hutech’s discussion of the limitations and common misconceptions about light pollution suppression filters.
LPS filters are available for 1-1/4″ and 2″ (48mm) eyepieces, as well as in numerous sizes to accomodate most popular camera lenses. Each filter lot is tested and a plot of the spectral response of the lot is provided with each filter.
[Above] Spectral response (% transmission vs. wavelength in nanometers) of the IDAS Light Pollution Suppression filter. Major emission lines generated by artificial lighting are also indicated. Note that this plot represents the spec target for LPS filters. The spectral response of each individual filter will vary. This is measured, plotted, and shipped with each filter produced:
Above is a sample of the filter lot data plot which is shipped with each filter.
The IDAS production criteria for filters are as follows, arranged from left to right (short to long wavelength) as plotted above:
| Wavelength (nm) | Pass/Block | Transmission |
| 365 | Block | 6.5% max |
| 405 | Block | 6.5% max |
| Pass | 60% min (avg) | |
| 436 | Block | 6.5% max |
| Pass | 92% min (avg) | |
| 546 | Block | 6.5% max |
| Pass | 75% min (avg) | |
| 590 | Block | 6.5% max |
| Pass | 75% min (avg) | |
| 623 | Block | 25% max |
| Pass | 80% min (avg) |
[Above] Off-axis spectral response (% transmission vs. wavelength in nanometers) of the IDAS filter.
| Filter Size | 31mm, 36mm, 48mm, SCT Filter with 48mm, 50mm, 52mm |
|---|
Fast Shipping and Professional Packaging
Due to our longstanding partnership with UPS FedEx DHL as well as other major international carriers, we are able to provide various shipping options. Our warehouse personnel will pack each item according to our strict requirements. Before they are shipped, your goods will be thoroughly examined and secured. Everyday, we send to thousands of clients in different countries. This is a sign of our determination to become the largest online retailer globally. The warehouses and centers for distribution are in Europe, as well as the USA.
Note that orders containing more than one item will be processed according to the specific item.
Before shipping before shipping, we'll inspect thoroughly the items you've purchased. Most orders are delivered within 48 hours. The estimated delivery time is between 3 and 7 days.
Returns
The inventory is always changing and we do not fully manage it because of the fact that many parties are involved, including our warehouse and factory. Therefore, the actual inventory could change at any time. It's possible that your order will be unable to fill when you have placed the order.
Our policy is valid for 30 days. If 30 days have gone without a trace since the purchase and we are unable to offer an exchange or refund.
In order for your item to be returned it must be in its original packaging, unopened and in the same condition as when you received it in. It must also be in its original packaging.
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