Antlia 1.25'' IR Pass 685nm Planetary Filter

Antlia 1.25" IR Pass 685nm Planetary Filter

£41.00✓ 2 year warranty


Out of stock due 15-20 working days

About this product

Model:  antlia_irpass_685_1.25

Antlia 1.25" IR Pass 685nm Planetary Filter

The Antlia IR Pass 685nm filter is an absorptive filter that allows infrared light with wavelengths of more than 685nm to pass through. At these longer wavelengths, the sensitivity of the unaided eye is reduced, so it is not suitable for visual observations. The filter is highly recommended for any planetary photography. At long-wavelength spectral range the atmospheric air turbulence (seeing) has much lower impact on the sharpness. The closer to the infrared band, planetary images are less disturbed by wavefront distortions in the atmosphere (seeing), result in the sharpest and highest contrast image possible.

By combining a luminance image taken with the IR-Pass filter, along with RGB and U-Venus filters, overall image sharpness is significantly enhanced and details of planets in different bands are taken.

The filter is also possible to image the other planets during daylight due to the dark background sky created by the 685nm IR Pass Filter.

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! 


  • 1.25" IR Pass 685nm
  • Ultra-thin filter cell to minimise vignetting and maximise clear aperture
  • Not suitable for visual observations
  • Helps improve the sharpness when planetary imaging
  • Edge blackened to eliminate internal reflections from stray light
  • 2mm+/-0.05mm glass thickness
  • Fine-optically polished on both sides 


Technical Data:

Schott optical substrate

1.25” mounted, (2mm+/-0.05mm)

Surface Quality: 60/40 (Refer to MIL-O-13830)

2 sides fine-optically polished to ensure accurate 1/4 wavefront

30 arcsec parallelism


Filter Ring:

1.25”( 28.5*0.6 )

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

Black Anodized Finish

Laser Engraving No Fading

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