IDAS NB2, NB3 dual narrowband filters

The NB2 and NB3 filters are dual line-pass filters which can be used with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras.

The NB2 filter passing the red Hα and the blue-green OIII lines

The NB3 filter passing the red SII and the blue-green OIII lines. These filters are enhance the contrast of the dominant lines found in emission nebulae without the time-consuming use of single-band filters. The resulting images can be used for luminance contrast enhancement of traditional RGB-balanced images or creation of images in various popular false-color palettes.

Note that a base filter which provides IR blocking is required in combination with these filters!

The most important features of the IDAS NB2 and NB3 nebula filters:

♦ Allows for about 4x increase in exposure time

♦ NB2: OIII and H-alpha pass (NB3: OIII and SII)

♦ Passbands slightly extended to longer wavelengths for still allowing the lines to pass in case of oblique incidence due to large angles, making the filter suitable for very fast optics

♦ Suitability for narrow-band imaging of diffuse emission nebulae and planetary nebulae

♦ High-quality anti-reflection coating

♦ Especially scratch-resistant hard coating

♦ Absorption of the urban scattered light (mercury, sodium vapor lamps, ...) and the nightglow

Exposure time extension - factor 4:

The IDAS NB2 allows exposure time to be extended by a factor of 4, but the most important lines in the deep-sky range are transmitted well over 90%.

Put simply, you can expose about four times as long until the sky background comes through, but the object appears much stronger and more contrasty against the background than without a filter.

Difference NB1 - NB2 - NB3 Nebula Filters:

All three filters are suitable for color and monochrome cameras, DSLR and system cameras. A combination of these three filters allows extreme narrow-band images with mono and color cameras.

• NB1: Triple filter with transmission at H-Beta, O-III and H-Alpha. Furthermore, the filter blocks Near IR light, no additional IR cut filter is needed. The NB1 is the most versatile filter. We also recommend the filter for astromodified DSLR and system cameras.
• NB2: Dual band filter with transmission at O-III and H-alpha. The contrast effect is very strong. Since the filter does not block near IR light, an IR cut filter is necessary. The filter is well suited for color astrocameras with built-in IR-cut filter, like astro modified DSLR-s.
• NB3: Dual band filter with transmission at in O-III and S-II. The contrast effect is very strong. An IR cut filter is also necessary here. This filter is ideal for the photography of objects that radiate in the S-II range (sulfur). These nebulae often still have an O-III component.