BAADER BESSEL U PHOTOMETRIC FILTER L-350 Ultra-thin filter cell to maximise

Ultra-thin filter cell to maximise the compatibility with most filter wheels

399 times the human eye SKU OF-60F3

Connections M42 x 0

Both telescope- and eyepiece-side barrels can be unscrewed to reveal T2 (M42 x 0

today you may prefer to dedicate it to directly controlling a computerized dome

BAADER BESSEL U PHOTOMETRIC FILTER L-350 Ultra-thin filter cell to maximiseThe Baader Bessel U filter is a precision grade photometric bandpass filter with a central wavelength window between 320 400nm. The UBVRI system was developed in the 1950s for the 0. 9m McDonald Observatory telescope and initially consisted of a Johnson UBV filter set, later extended by Cousins to include the R and I filters for the red region of the spectrum. The filters of the extended UBVRI system according to Johnson and Cousins include: U