Baader OIII 2" 9nm Super-G CMOS-Optimized Filter

Baader OIII 2" 9nm Super-G CMOS-optimized Filter

>Baader OIII 2" 9nm Super-G Filter Highlights

• O-III Super-G filter with 9 nm FWHM and a maximum transmission of 97%

• For visual and photographic observation of planetary nebulae and supernova remnants, even with small telescopes

• Can be used as a "Super-G filter" replacement for RGB photography. While regular G-filters suffer from bad seeing due to air turbulences, the narrow range of 9 nm passes less thermal noise, i.e. sharper images. Nevertheless, the transmission window is large enough not to be considered a pure narrowband filter.

• CMOS-optimized coating technology with much steeper slopes of the filter passband - for increased contrast, longer life and to avoid reflections.

The new Baader O-III filter is designed for deep sky visual observing and photographing those gas nebulae in which doubly ionized oxygen fluoresces. It is superb for planetary nebulae, supernova remnants, and many large-emission nebulae. With an FWHM of only 9 nm and equipped with the CMOS-optimized coating technology, it darkens the sky background, blocking stray light much better than its 10 nm predecessor (Baader (10nm) O-III Filter visual) for outstanding visual contrast on a large number of the nebula. But the narrower FWHM is not the most important improvement. More important is the significantly better blocking aside of the O-III wavelength, as well as even steeper transmission slopes and a broad plateau in the transmission range. With a transmission of 97% for the emission line at 500.7 nm, practically all the light of the nebula passes through the filter. At the same time, this filter can be used photographically for practically any focal ratio from f/1.8 to f/12 without passing any light of the H-beta line. This makes the Super-G filter just as ideal for use in areas with high light pollution.

The 9 nm O-III filter can be excellently used photographically on all telescopes, especially with a DSLR or an astronomical OSC color camera. It offers all the advantages of the CMOS-optimized Baader filters such as Reflex-Blocker™ coating against reflections, planeoptical polishing, and age-resistant Life-Coat™ coating. For monochrome cameras, we recommend the even stronger Narrowband (6,5 nm) and Ultra-Narrowband (4 nm) filters, which are available specially adapted for different aperture ratios. For this comparatively broadband 9 nm filter, pre-shifting is not necessary at focal ratios faster than f/4, thus it can be used at all focal ratios.

The filter has the same thickness as the 2" Baader LRGB filters. This makes it suitable for use as a "super G filter": In the transmission range of the normal green filter (490-580nm) there are no emission lines other than OIII; H-Beta at 486 nm is already covered by the RGB blue filter. So, when using the 9 nm O-III filter instead of the standard RGB green filter, emission nebulae are consequently emphasized much more strongly, while the stars appear fainter.

The Baader OIII Filter also offers all the advantages of the CMOS-optimized Baader filters:

• Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio

• Reflex-Blocker™ coatings, for largest ever freedom from halos, even under most adverse conditions concerning aux-optics

• Identical filter thickness to existing standards, with utmost care for parfocality

• Blackened edges all around, with filter-lead-side-indicator in the form of a black frontside outer rim, to additionally eliminate any reflection due to light falling onto the edge of a filter

• Each filter coated individually, with a sealed coating edge (NOT cut out of a larger plate with coatings left exposed

• Life-Coat™: evermore hard coatings to enable a non-aging coating for life – even in a most adverse environment

About Life-Coat

A Baader Planetarium exclusive. Filters incorporating Baader Planetarium’s Life-Coat™ technology are so durable that Baader Planetarium warrants 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 fail for a lifetime. Life-Coat™ coatings resist moisture, temperature extremes, and are hardened to withstand normal cleanings.

Baader Planetarium guarantees their Life-Coat™ coatings will not peel, flake, or physically degrade and will withstand repeated cleaning with fine optical cleaning equipment. The Limited Lifetime Warranty applies to the original purchaser and does not cover failure from misuse, physical damage through improper handling, or improper cleaning.

Technical Features

• Transmission Range: OIII

• Filter Thickness without Cell: 2 mm

• Half Bandwidth: 9nm

• Central Wavelength: 502nm

• AR-Coating: Reflex-Blocker™ hard-coated, dielectrically coated, planeoptically polished

• Filter Size: 2"

• Filter Usage: CMOS, Contrast Enhancement, OIII, Planetary

• Filter Mounted?: Mounted (LPFC 6mm)

• Type of Filter: Narrowband

• Single or Set?: Single Filter

• Filter Shape: Round