Antlia ALP-T Dual Band 3.5nm SII & H-beta Filter – 2” Mounted

Description

Antlia ALP-T dualband 3.5nm SII&H-beta Filter

The ALP-T dual band 3.5nm SII&Hb filter is a dual narrowband filter, which lets the deep red Sulfur-II 672.4nm and the blue Hydrogen-Beta 486.1nm lines through and is primarily engineered for color cameras to assist astrophotographers taking deep sky images with superior SNR(Signal to Noise Ratio). With an FWHM half-bandwidth designed at 3.5nm and achieving an optical density (OD) of 4.5 on unwanted wavelengths, it works strongly in blocking light pollution, moonlight, and airglow, leading to enhanced contrast in nebulae images by effectively passing the SII and H-beta emission lines signal only.

It is a significant addition to the popular Antlia ALP-T dual-band Ha&OIII filter and enables false-color images and narrow-band nebula images using OSC. When capturing data with this filter, the nebulae are recorded with high signal-to-noise ratios and greater contrast than without it.
The combination of these two dual band Ha&OIII and SII&H-beta filters allows extreme narrow-band images with OSC cameras by capturing the spectral data from 4 channels i.e. Ha/OIII/SII/Hb. The spectrum of these four channels can be separated and recombined into various color palettes in your post-processing. The resulting images can be used for luminance contrast enhancement of traditional RGB-balanced images or the creation of images in various popular false-color palettes such as H-O-Hb, S-H-O, H-S-OHb, H-O-O, etc.
The advanced multi-coatings on Antlia ALP-T dual-band filters effectively isolate the red, Ha line, blue-green, OIII line, deep red SII, and the blue H-beta lines from emission nebulae, with almost total suppression of optical density (OD)4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that both the ALP-T dual band Ha&OIII version and SII&Hb version create a superior signal-to-noise ratio and better contrast in your OSC images whether used in