Meade Series 4000 #905 Variable Polarizing Filter (1.25")

The # 905 Variable Polarizer system includes 2 Polarizer filters mounted in a specially-machined cell, for glare-reduction in observing the Moon. Rotate the thumbscrew at the side of the unit to achieve light transmission between 5% and 25% of its original value. The # 905 inserts into the diagonal prism of the telescope, followed by an eyepiece.

This item is basically sunglasses for your telescope, for lowering the bright glare and overexposure of the moon which prevents comfortable viewing.The advantage of this design over other polarizers, is to use the other polarizers one has to constantly take out the eyepiece to readjust the amount of polarization.This item is exclusively for viewing, for photography use the individual polarizing filters.