2" Single Polarizing Filter (BPPOL2)

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A polarizing filter is an excellent filter choice for lunar viewing. It provides variable neutral density (it darkens or lightens) as it is rotated, accommodating the different lunar stages.  This filter is a single stage polarizing filter and must be used with a diagonal mirror, such as our MaxBright Diagonal (PMDMAX), to achieve the polarizing affect. This polarizer can similarly be used with the Herschel Prism (BPHERP) for solar viewing, but must always be used in addition to the ND3.0 filter (the ND3.0 filter must always remain in the Herschel Prism for viewing safety).  

These filters come in two sizes: 1.25" (BPPOL125) and 2" (BPPOL2)

  • For step-less brightness-control in combination with a diagonal or a Herschel Wedge. Perfect for observing moon or planets or for solar observations with Herschel Wedge or AstroSolar Safety Film ND 5.0.
  • You can change the brightness if you rotate two single polarizing filters against each other, to adjust the brightness according to your magnification. You can mount one 1,25" filter in the eyepiece and a 2" filter in the reducer piece from 2" to 1.25
  • Enhances contrast during planetary observation.
  • For solar observation use it behind a Baader Herschel Wedge. The Herschel wedge already polarizes the light, so that one single polarizing filter is sufficient.
  • Please note: Polarizing filters (and all other eyepiece filters) may never be used without an appropriate solar filter (AstroSolar front filter, Herschel Wedge).

When either lunar or solar viewing, the filter can be screwed onto the barrel of a 2" eyepiece or onto our 1.25" Eyepiece Adapter (ADA125). Note that in the case of our ADA125, you may need to add our 2" Barrel Extension (A3703) to accommodate 1.25" eyepieces with extra long barrels. 

IMPORTANT NOTE:  When using with the Herschel Prism you'll need to use the BP2SR spacer to prevent 2" eyepiece barrels from contacting the polarizing filter's surface and causing damage.