Antlia ALP-T Dual Band 3nm SII&OIII Filter - 2'' Mounted

The ALP-T dual band 3nm SII&OIII filter is a dual narrowband filter, which lets the deep red Sulfur-II 672.4nm and the blue-green OIII (500.7nm) 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 3nm 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 OIII 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 main features and application

Passes SII 672.4nm and OIII 500.7nm lines

Capturing of the two main emission wavebands in the deep red and blue-green at the same time

Ultra FWHM 3nm design allows for increasing exposure time and capturing detailed nebulae signal

Designed to be used primarily with color cameras to capture cleaner data or used as Luminance filter mono cameras to save imaging time

Suppression of optical density (OD)4.5 on unwanted wavelengths improves SNR( signal-to-noise)

Near IR (NIR) is blocked up to 1100nm

Ideal flat-top and moderate bandpass reducing spectrum downshifts

Ion Gun Assisted Deposition of double-sided multi-layer coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter

Halo suppression anti-reflective coating is used to minimize halo and internal reflections

Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8

Blackened edges of unmounted sizes to minimize internal reflections

Antlia's ever-trusted coating technology makes filter durability very reliable

Recommended to be used with ALP-T Dual Band Ha&OIII filter to create images with better SNR( signal-to-noise) and better isolation between the channels

Recommended to use the filter with optics f-ratios slower than f/4 for best performance, for optics faster than f/4, pre-shifted highspeed version is a better choice

While primarily designed for use with color cameras, the filter is also highly effective with monochrome cameras to save imaging time

Technical Specifications:

Filter Ring:

2'' (M48*0.75)

The advanced multi-coatings on Antlia ALP-T dual-band series filters effectively isolate the red, Ha line, blue-green, OIII line, and deep red SII lines from emission nebulae, with almost total suppression of optical density (OD)4.5 on unwanted wavelengths from light pollution, moonlight, and airglow.

The ALP-T dual band Ha&OIII version, SII&OIII version and SII&H-beta create a superior signal-to-noise ratio and better contrast in your OSC images whether used in urban or rural areas, making them excellent choices for astrophotographers aiming to capture high-quality and more detailed celestial images.

When you buy 2 filters of the Ha&OIII version and the SII&H-beta version or the Ha&OIII version and   SII&OIII version as a COMBO, you can get them at better prices.

Antlia ALP-T Dual Band Ha&OIII versionr: Dual band filter with a very narrow passband in H-alpha and OIII to achieve a higher signal-to-noise ratio.

Antlia ALP-T Dual Band SII&OIII version: Dual band filter with a very narrow passband in SII and OIII to achieve a higher signal-to-noise ratio.

Antlia ALP-T Dual Band SII&Hb version: Dual band filter with a very narrow passband in SII and H-beta. This filter is ideal for increasing contrast of nebulae that emit in the sulfur and H-beta range using OSC. It provides additional feature separation and isolation in Hb areas.

Filter Ring:

2''(M48*0.75)

Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture

Black Anodized Finish

Laser Engraving No Fading

Not Recommended:

Solar imaging

Night visual observation

Not Permitted:

DO NOT LOOK AT THE SUN WITH THIS FILTER DIRECTLY

Serious eye damage will result if you fail to observe the warning.

Spectrum Curve:

Not Recommended:

Solar imaging

Night visual observation

Not Permitted:

DO NOT LOOK AT THE SUN WITH THIS FILTER

Serious eye damage will result if you fail to observe the warning