During the current elongation 2016-17 I made a number of images by using of the Baader Planetarium Ca-K filter, centered on 395nm, developed for imaging the Sun at that specific wavelength. I am not really satisfied of this filter, it seems to deliver less sharp images compared with my previous Astrodon UV 355 nm. For this reason I returned to Meade W47 + Astronomik IRcut combination, that based on Pellier’s test is a very good combination for imaging Venus clouds. I am planning to purchase an Astrodon photometric UV filter, it should match closely the old Venus UV.
As can be seen from the below images seeing did not cooperate so far, but I hope to do better in the next weeks between the greatest E elongation and the inferior conjunction.
I have now (Jan 2017) replaced the Ca-K filter with the Baader U-filter which is centered on 350nm. It seems a real improvement compared to the 395nm filter and is very similar to my previous Astrodon UV:
As the elongation progresses Venus’ declination increases and seeing improves. My Baader U-filter proved to be a good one but I still believe that the Astrodon filter is slightly better.