Antlia ALP-T Dual Band Highspeed 5nm Filter
Antlia ALP-T Dual Band Highspeed 5nm FilterAntlia ALP-T Dual Band Highspeed 5nm FilterAntlia ALP-T Dual Band Highspeed 5nm FilterAntlia ALP-T Dual Band Highspeed 5nm Filter

Antlia ALP-T Dual Band Highspeed 5nm Filter

£308.00✓ 2 year warranty


1x in stock shipped 1-2 working days

About this product

Model:  antlia_alp_t_dual_highspeed_5nm_36mm

Antlia ALP-T Dual Band Highspeed H-alpha / Oxygen III 5nm Ultra-Narrowband Filter

For One Shot Colour CCD / CMOS / DSLR Imaging - Simultaneously Capture H-alpha and Oxygen III

The ALP-T Dual Band 5nm Highspeed Filters are further optimised to work with high-speed imaging systems by shifting slightly the passband and centre wavelength. Using these highspeed filters between optics f/2.2 and f/3.6 shows much stronger contrast in nebulae imaging compared to the standard version.

For optics f-ratios slower than f/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. 

The Antlia ALP-T dual band 5nm series filter is a dual line-pass filter that was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on the ALP-T ultra dual band filter effectively isolate the red Ha and the blue-green OIII lines light 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 our ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.

The filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post-processing efforts to isolate faint details from the background light pollution.

IMPORTANT: These filters are NOT designed for observing or photographing the Sun. DO NOT use these filters to observe or photograph the Sun. If you do it will result in permanent eye damage! 


  • Designed especially for fast optics - ideally suited for f/2.2 to f/3.6
  • High transmission of H-Alpha and Oxygen III emission lines (peak transmission 88% for Ha & 82% for OIII)
  • FWHM: Ha 5nm, OIII 5nm
  • Engineered specifically for use with DSLR, CMOS, and CCD colour cameras
  • Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
  • 36mm unmounted or 2" mounted filters
  • 36mm supplied with a B4836 filter holder enabling it to fit a 2" / M48x0.75 filter thread
  • 2" mounted filter has an ultra-thin filter cell to minimise vignetting and maximise clear aperture
  • 300-1050nm ≥OD4.5 blocking of unwanted wavelengths for improved signal to noise
  • Near IR (NIR) is blocked up to 1050nm
  • Extremely steep bandpass edges minimises internal reflections
  • Ideal flat-top and moderate bandpass reducing spectrum down shifts
  • Supplied in a protective plastic case with EVA foam lining
  • 2mm+/-0.05mm glass thickness
  • Fine-optically polished on both sides 
  • Ion Gun Assisted Deposition coating technology making it a highly consistent and accurate light pollution suppression filter

Transmission Chart

Blue Line - Represents the transmission curve of the filter.

The Major Emission Lines of Nebulae: H-α (656.3nm), H-β (486.1nm), OIII (495.9nm) and OIII (500.7nm)

The Major Emission Lines of Artificial Light Pollution: Hg / Mercury (435.8nm, 546.1nm, 577nm and 578.1nm), Na / Sodium (598nm, 589.6nm, 615.4nm and 616.1nm)



  Hydrogen-alpha Oxygen III
FWHM 5nm 5nm
CWL (Central Wavelength) 657.8nm 502.2nm
Peak Transmission 88% 82%
Blocking ≥OD4.5 @ 300-1050nm
Filter Thickness 2mm+/-0.05mm

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