Brand: Antlia

Antlia ALP-Dual Band 5nm Ha&OIII Golden Filter (ALP-T-2)


Brand: Antlia

Antlia ALP-Dual Band 5nm Ha&OIII Golden Filter (ALP-T-2)


Filter technology continues to advance and deliver better results in your astrophotography. Antlia has you covered with this premium dual band filter. You'll be amazed at what it does for your deep sky imaging.
$509.95 CAD

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$509.95 CAD

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The Antlia ALP-T dual band Golden 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot colour (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 our 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 background light pollution. As Antlia ALP-T dual band 5nm filter looks golden yellow to the naked eye, we also call it the Golden filter.

When we design filters for astronomy imaging systems, we look at how they will work together with optical systems, carefully designing the blocking and bandpass parameters to achieve an optimum result. The out of band blocking rate is a very important performance index since it is designed to sharply attenuate off unwanted band wavelengths.

Each filter is individually tested and scanned to ensure that the quality meets the high performance parameters. The end result is a filter that achieves excellent signal-to-noise but with a higher production cost. We believe the price to performance ratio compares more favourably than similar premium filters in the market.

Quick Overview

  • Engineered specifically for use with DSLR, CMOS, and CCD color cameras
  • Suppression of optical density (OD)4.5 on unwanted visual wavelengths adds signal-to-noise
  • 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 ratioincreases
  • Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
  • Near IR (NIR) is blocked up to 1100nm

Not Recommended for solar imaging or night visual observation

NOTE: DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will result if you fail to observe the warning.


  Hydrogen-alpha Oxygen 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 2mm+/-0.05mm

Customer Reviews

Based on 2 reviews
Antlia ALP-T-2 Dual Band Filter

I was looking for a Dual Band filter I can use with fast optics. (I have one for slow optics). I already have a set of Antlia 2" 3nm LRGBSHO filters which are great, so I thought I would try the ALP-T 5nm. BTW it is 5nm so it works with fast optics down to f/3.3. A narrower passband would block a lot of signal at fast f-ratios.

The purchase experience was fast and efficient.

First night out: full moon, no true astronomical darkness. I shot the Veil Nebula at 200mm f/4 with an ASI071MC Pro and got a really good picture. No halos, the whole nebula complex was visible in a single one of the 300" exposures I took.

Antlia ALP-Dual band filter

This is the best filter for under 1000 bucks, very happy with the outcome.

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