Astronomy Specialist



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The new Antlia ALP-T Golden Dual Band filter is specifically designed for astrophotography with colour DSLR, CMOS or CCD cameras in areas with heavy light pollution. Its two 5nm passing bands are exceptional at isolating nebulae emissions in H-Alpha and OIII. The optical density of 4.5 suppresses unwanted wavelengths from light pollution, moonlight and skyglow, resulting in superior signal-to-noise ratio and better contrast.

The 36mm unmounted variant comes with a handy mounting adapter so you can use it with 2" filter drawers and accessories!

Like all Antlia filters, the Golden Dual Band filter has excellent halo suppression, making imaging of targets surrounded by bright stars such as the Horsehead Nebula pain-free.



IC 434 by Hyunsu Lee | SkyWatcher 130mm f/5 with MPCC, IMX571, 2" Antlia Golden Dual Band filter, 300 sec x 24, Bortle 5.


  • It blocks the artificial light from mercury vapour lamps, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
  • Maximum transmission of the main nebula emission lines at OIII (500.7nm) is >82% and H-alpha (656.3nm) is >90%. Good signal is still achievable with optics as fast as f/3.
  • Two transmission bands with a bandpass of 5nm. OD4.5 @ 300-1100nm.
  • Ideal for urban areas with extreme light pollution.
  • It incorporates an IR/UV-Cut filter that is necessary in astrophotography, especially for astronomy cameras that are sensitive to the infrared radiation.
  • Ultra-thin filter cell to maximise the compatibility with most filter drawers.
  • Ideal flat-top and moderate bandpass reduces spectrum down shifts.
  • Good performance at focal ratios slower than f/3.

To even further enhance the contrast, and suppress the stray light and internal reflections, Antlia applies edge-blackening coating on each filter. Each filter is individually tested to ensure a high quality standard. The tight tolerance of the filters substrate assure a maximum deviance of ±0.05 from specifications making these filters parfocal.

DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will occur.



Passing band 5 nm (FWHM)
Glass thickness

2.0 mm ±0.05

Optical flatness

1/4 λ (wavefront)

Bandpass transmission H-a >90%, OIII >82%
Off-band transmission OD4.5 @ 300-1100 nm
Coating Double-sided multilayer nano-coating
Surface quality 60/40 (in accordance with US military watch MIL-O-13830)
Parallelism 30"
2" - AN-ALP-T, 36mm - AN-ALP-T-36



IC 63 by Hyunsu Lee | SkyWatcher 130mm f/5 with MPCC, IMX571, 2" Antlia Golden Dual Band filter, 300 sec x 32, Bortle 5.



NGC 2244 by Hyunsu Lee | SkyWatcher 130mm f/5 with MPCC, IMX571, 2" Antlia Golden Dual Band filter, 300 sec x 30, Bortle 5.

Customer Reviews

Based on 3 reviews
Greg England
Works well at F2

Had a few hours last night to image Vela with the Samyang 135mm F2 and ZWO 2600MC pro, Filter worked extremely well at F2 slightly better than my much beloved IDAS NBZ due to the narrower bandpass. Next clear night will try on the RASA 8

Greg England
OSC Dual Band Filter

After a few initial issues with internal reflections in the image train I have had very good results from this filter. Had been waiting for a while to try it out but finally had a clear night last week. Images show no halos around bright stars.
Hoping to get another clear night soon to try in RASA 8 and compare to the IDAS NBZ at F2, will update review once completed.
Transmission of both O3 and Ha is very good.
A much better option than the L extreme.

Neil Jones
Golden Filter

I’ve had a chance to try it out. Like what I’ve seen so far

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