- Variable polarizing filter improves subtle detail in Moon and bright planets
- Cuts down on glare of bright lunar and terrestrial images
- Transmission continuously variable from 2-40% for a wide range of viewing situations
- Includes convenient short profile 1.25" eyepiece tube to make it easy to change eyepieces without having to remove and replace filter element
While observing the moon or planets, there is often too much light that washes out subtle details. This glare can be cut back using neutral density filters or polarizers. Polarizers are also helpful for splitting binary stars by reducing glare and diffraction around the brighter star of a binary pair.
The variable polarizing filter makes this even better by stacking two 1.25" polarizing filters together. By rotating the two elements, light transmission can be varied between about 2% and 40%. This filter retains true color balance since all wavelengths are transmitted uniformly over the entire spectrum.
This BST StarGuider polarizing filter also includes a very handy, short profile 1.25" eyepiece tube. The two filters are attached to this tube, allowing you to quickly change eyepieces without having to screw/unscrew the filters to individual eyepieces. However, the addition of this adapter requires about 1" of additional in-focus travel to compensate for its length in the optical path. Also, note that the inside depth of this tube is only 14mm (0.55") so your eyepiece will stick out by a bit if its 1.25" barrel is longer than this.
The two polarizing elements can also be unscrewed to obtain two polarizing filters (see photo 2) which can be used for day time photography or to improve contrast in images when only a little reduction in transmitted light is desired. The filters have a standard 1.25" thread (M28.5 x 0.6) so they can be screwed on to any virtually any standard 1.25" eyepiece or accessory.
- Total length = 41.6mm (1.64")
- Clear aperture = 27.0mm (1.06")
- Weight = 1.2oz.
- Made in China