ALP-T Dual band 5nm&B4836 Ha&OIII filter


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ALP-T Dual band 5nm&B4836 Ha&OIII filter 36mm

The Antlia ALP-T dual band 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's or 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 isolates 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 ackground light pollution.

Application and Performance:

  • Engineered specifically for use with DSLR, CMOS, and CCD color cameras
  • Suppression of optical density (OD)4.5 on unwanted visual wavelengths offers very good signal-to-noise ratio
  • Extremely steep bandpass edges minimize internal reflections
  • Ideal flat-top and moderate bandpass reducing spectrum down shifts
  • Ion Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
  • Good performance at focal ratios faster than F3.0 with contrast increasing as focal ratio increases
  • Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
  • Near IR (NIR) is blocked up to 1100nm


Technical Data: 


Hydrogen Alpha

Oxigen III

FWHM 5nm 5nm
CWL (Central Wavelength) 656.3nm 500.7nm
Peak Transmission 90% 82%
Blocking ≥OD4.5 @ 300-1100nm ≥OD4.5 @ 300-1100nm
Filter Thickness 2mm+/-0.05mm


    Available Sizes:

    • Unmounted:Dia 36mm (2mm thickness)

    Not Recommended:

    • Solar Observing and imaging
    • Visual observation
        Serious eye damage will result if you fail to observe the warning.


    You will see the same images on the manufacturer's website. The difference is that we decided to slightly improve the images in Photoshop, however whilst these images below had been improved, on the other hand we also had to reduce the resolution due to the image size limitations on our website.



    ALP-T Dual band 5nm&B4836 Ha&OIII filter