Another unique new filter from Baader Planetarium. For the first time, amateurs can now record cloud structures on Venus. The Baader Venus Filter enables amateurs to successfully image in the deep UV, a spectral region normally inaccessible.
The latest coating technologies permit the Baader Venus Filter to transmit from 300nm to 400nm, with a peak transmission of 80%! The filter completely blocks the rest of the region from 200nm to 1500nm, through the use of a complex 20 layer dielectric coating stack, on top of a special optically polished UG-11 substrate. Until now, amateur efforts typically relied upon deep violet colored filters, or combinations with simpler interference filters, which do not provide the high transmission and efficient rejection outside the important spectral region from 320nm to 390nm. Given the poor transmissions of many optics in the UV and the lower sensitivity of some CCDs to this wavelength, high filter efficiency and complete rejection at longer wavelengths becomes paramount to recording good contrast at reasonable exposures. The same high optical quality and features as the other Baader filters ensures the highest contrast and sharpest images possible.
Interestingly, the solar Calcium K-Line is also within the pass band of this filter. This opens up the exciting possibility for recording flare structures on the solar disk or edges.
The Baader U Filter has become the choice of UV imagers exploring the UV world of landscape, floral, and even forensic imaging. The latest 1.25" filter now has even higher transmission and improved out of band blocking. The filter cell has a standard M28.5x0.6 thread.
Please Note: The Baader Venus filter is only applicable for imaging of Venus with Webcam, Digital, and CCD cameras (Visual Observation is impossible, due to the eye's insensitivity to the UV). For successful Venus imaging, we recommend the use of a UV sensitive astro CCD camera (ie, SBIG ST-2000XM) and at least a 5" telescope, or a webcam and 8" telescope.
May 31, 2013
1.25in Baader UPros:
Accurate,Optically The Same As 2,Lightweight,Easy to UseCons:
Difficult To Clean,Potentially DelicateComments:
My use for this filter is UV photography. I already own the 2" version of the Baader U, and this filter is the standard workhorse for UV bands around 365 nm. The 1.25" is of course much smaller, and easier to use for this reason, especially in the field. I am happy to report that my specimen of the 1.25" is optically identical to the well-known 2" version (in other words, no detectable IR leak in my tests so far). This filter uses delicate multi-layer dielectric coatings on both external surfaces, so it must be treated with care. It should never be touched, and must be cleaned with care. Absolutely do not dry wipe it (not even with a lens cloth or lens brush). It can be cleaned successfully with pure alcohol and a lens paper towel, applying a very low pressure on the optical surfaces. For use in photography, this filter (like any Baader 1.25in filters I am aware of) can be removed from its 1.25in mount and remounted in a 30mm or 30.5mm camera filter mount.
This review was provided courtesy of AgenaAstro.comJan 2, 2011
Difficult To FocusComments:
The filter is used in combination with a near infrared digital SLR camera to create UV photographs. I had to purchase the Baader U filter to replace a filter that I accidentally broke. After extensive research, I found Agena Astro products on line. The staff were nice and promptly provided accurate answers to my questions, and the price was very competitive.
This review was provided courtesy of AgenaAstro.comNov 6, 2009
Great UV performance for the price.Pros:
Quality Lenses,AccurateCons: Comments:
I bought this filter for use with with digital photography and some astro-photography. The filter has performed wonderfully and is one that I depend on to help give capture UV reflective pictures with a 48->52mm step-up ring.
Although pre-focusing is required, due to the nature of UV captures this is an acceptable limitation.
This review was provided courtesy of AgenaAstro.comSort by