Baader UV Filter 2" for Venus photography

UV Filter 2" - for Venus photography

It is nearly impossible to observe Venus´ cloud structures visually. Commonly, amateur astronomers believe that these structures can only be veryfied with relatively big apertures and special telescopes.
But the main problem is the correct filtering. By combination diverse colour and interference filters it is possible to enhance contrast - on the other hand, the subtle cloud structures get lost because light of >400 nm enters the camera.

The Baader Venus filter lets only pass the parts of light where the cloud structures are visible, the UV light.

Thus makes capturing Venus in UV light possible, detail becomes visible even in smaller telescopes. All other wavelenths are blocked. Das macht die Fotografie der Venus im UV Licht möglich, Strukturen werden bereits in kleineren Geräten sichtbar. Jeder weitere Lichtdurchlass wird gestoppt. Now the cloulds are only detectable.
The upper picture has been made by H. Rietze (Baader Planetarium) only two days before the Venus transit. The overlappings caused by Venus´ atmosphere are clearly visible.

The spectral transmission curve

Here one can see that the filter only opens between 300 and 400 nm. The human eye has nearly no sensivity in this range but CCD sensors have. So this filter is recommended only for photographical applications. This filter is precise worked. The substrate is UG-11 glass (2 mm thick) by Schott, treated with a 20-layer dieletrical coating. Cell height: 6 mm without external thread, 8 mm with M48 external thread

♦ Baader UV pass filter