Antlia 1.25'' U-Venus Planetary Filter

Antlia 1.25" U-Venus Planetary Filter

£206.00✓ 2 year warranty


3x in stock shipped 1-2 working days

About this product

Model:  antlia_u_venus

Antlia 1.25" U-Venus Planetary Filter

Antlia Venus-U filter is designed for imaging the cloud structure of Venus and Jupiter with CCD cameras on a telescope. Cloud details primarily reflect in the ultraviolet band which cannot normally be imaged using broadband filters. The Venus-U filter uses the latest dielectric interference coating technology to achieve high transmission efficiency and exceptional isolation of the critical UV bandwidths. The filter effectively blocks the contrast damaging frequencies beyond 400nm which typically swamp the ultraviolet cloud details on camera sensors. Like the highest quality Antlia LRGB filters, the U-Venus filter minimises halos around bright stars and increase the contrast.

Recommendations in the use of this filter:

1. When U-Venus filter is used with a planetary camera, it is recommended to remove any protective UV-IR window in front of a colour planetary camera because this filter may attenuate transmittance of the critical ultraviolet band that contains cloud details.

2. The lower the frequency in the UV band, the longer will be the exposure to achieve sufficient signal in your image. The sensitivity of most sensors also decreases rapidly at shorter UV wavelengths.

3. It should be noted that when using DSLR to shoot ultraviolet flowers, the camera needs to be specially modified to remove the infrared cut filter inside the camera.

4. In non astronomical use, the lighting conditions may block UV transmissions e.g. the UV contents of electronic flash emission, because of a combination of lower emission at shorter wavelengths and increased absorption by the glass of the flash tube. These factors combine together to require a substantially increased exposure time (for continuous UV sources), UV intensity and ISO sensitivity as the wavelength decreases.

Non-astronomical applications:

Use for general UV photography (flowers, health of plants, insects, forensics and medical imaging)

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" U-Venus filter
  • High transmission of UV bandwidths
  • 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 

Example Image


Optical substrate:

Thickness: 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


OD3(>0.001)@ 200-1050nm

2 sides Dielectric multi-coating

Single / Non-glued substrate


Filter Ring:


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

Black Anodized Finish

Laser Engraving No Fading

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