Baader SLOAN/SDSS (ugriz´) Filter Set 2" - photometric

Baader SLOAN/SDSS (ugriz´) Filter Set 2" - photometric

In 2000, a new era in photometry began: with the Sloan Digital Sky Survey (SDSS), a 2.5 m telescope at Apache Point Observatory (New Mexico, USA) surveyed one third of the sky in five wavelengths. A camera with a total of thirty large CCD sensors with 2048×2048 pixels each was used, each in five rows of six sensors. In front of the sensors was a u´g´r´i´z´ filter set for five non-overlapping wavelength windows around 355.1, 468.6, 616.6, 748.0 and 893.2 nm; light pollution such as the airglow at 558nm and the mercury line at 546 nm were masked out. This system was also used for the Pan-STARRS project; the broad data base of these two surveys makes them very well suited for calibrating images. Another advantage are the wider transmission windows, which allow fainter objects to be measured in a shorter time.

Even though the six Sloan filters have a different characteristic than the UBVRI filters, there are now the appropriate algorithms to compare the data with each other or to convert them into each other. Therefore, the Sloan photometry system is gaining more and more importance. At present, UBVRI filters still dominate in amateur circles, but Baader not only offers unmounted Sloan filters for professional telescopes, but also in the sizes and mounts commonly used by amateurs. In the coming decades, it is expected that the Sloan system will also become more widespread in amateur circles, which is why Baader Planetarium´s SLOAN filters are also available in the common filter sizes for amateur telescopes as well as in the large format 100x100 mm. The SLOAN z´ filter is currently not included in the scope of delivery, as its function can usually also be taken over by the UBVRI -I- filter.

The same technology is used for the Sloan filters as for the CMOS-optimized narrowband and LRGB filters. Here, too, the lifetime Life-Coat™ guarantee applies.

Ready for the future

At a time when common filter types often disappear from the market without warning, with these filters Baader wants to offer all users a way to build on previous data obtained with UBVRI or Sloan filters. Long-term availability makes it possible for amateurs to enter with a limited budget and a small set of filters to expand in the long term. Therefore, Baader has resisted the temptation to improve the filter lines and has done the utmost to improve the filters in durability and applicability.

CMOS optimized filters from Baader-Planetarium

The completely redesigned, CMOS-optimized filters from Baader work excellently with all CMOS cameras. The new ultra-sensitive CMOS sensors require special filters to get the most out of the images. These sensors are much more sensitive to reflections and halos. Baader has taken this trend into account with the new CMOS-optimized filters. The filters are the new standard in astrophotography with CMOS sensors.

The features of the new CMOS-optimized filters from Baader:

Increased contrast due to narrower full width at half maximum (FWHM);

Reflex blocker coatings for maximum insensitivity to reflections with correctors, reducers and similar auxiliary optics;

All filters have identical thickness for parfocality - no need to refocus due to different filter thicknesses;

All filters have blackened edges with filter front side marking (black outer edge at the front side), thus additionally avoiding any reflection also at the filter edge;

Each filter is individually fine optically polished and coated, with sealed coating edge. This prevents the penetration of moisture.

Life-Coat stands for an even harder and age-resistant coating, thus the fiter can withstand the most adverse conditions and offers full filter performance even after years;

Each filter comes in a stackable filter box for optimal storage and transport;

Life-Coat™: „Limited-Lifetime-Warranty” for CMOS-optimized Baader filtersFilters equipped with Baader Planetarium´s Life-Coat™ technology are so durable that Baader Planetarium guarantees the coatings for the life of the filter. Baader Planetarium has developed Life-Coat™ using materials and processes that result in coatings that will not degrade or age for the life of the filter. Life-Coat™ coatings resist moisture, temperature extremes and are hardened to withstand normal cleaning.

Baader Planetarium guarantees that the Life-Coat™ coatings will not peel, flake or physically degrade and will withstand repeated cleaning with fine optical cleaning agents. This limited lifetime warranty applies to the original purchaser and does not cover failures due to misapplication, physical damage due to improper handling or improper cleaning.