Antlia's 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 minimizes halos around bright stars and increase the contrast.

Recommendations in the use of this filter:

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

Filter Ring:

• 1.25” Mounted (M26*0.6 thread)
• Ultra-thin filter cell to minimize vignetting by maximizing possible clear aperture
• Black Anodized Finish
• Laser Engraving, No Fading

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
• Tave＞80%
• OD3（＞0.001）@ 200-1050nm
• 2 sides Dielectric multi-coating
• Single / Non-glued substrate

Not Recommended:

• Solar Observing and imaging
• Visual observation
• DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. Serious eye damage will result if you fail to observe the warning.