UBVRI Bessel V Filter 2"

The Baader UBVRI Bessel V Filter 2" is a 2" x 2 mm photometric bandpass filter used to determine the brightness of stars in precisely defined spectral ranges of light, suitable for focal ratios from f/15 to f/1.8. The V-filter provides an inexpensive introduction to photometry, corresponding approximately to visual brightness and serving as an optimal tool for learning photometric techniques. Manufactured with advanced ion beam coating technology and featuring Reflex-Blocker hard coatings with sealed edges (Life-Coat™), it is compatible with both modern CMOS and older CCD camera technologies and mounts in a Baader Low Profile Filter Cell. These Bessel-UBVRI filters remain the standard and are the most widely used in amateur circles such as the AAVSO.