polarizer filter

Hello,
Is it true that if i have a extension eypiece w/ threads and attach a polarizer filter to that, then attach a 2nd polarizer filter to an eyepiece, I will be able to control contrast of the moon and other bright objects (jupiter,ect)?? A guy that i know said this works by loosening the thumbscrew on the extension and rotating the eyepiece. What is the difference between a polarizer and neutral density filter? I have a meade lx90, will an extension work w/ it? Thanks in advance, T. J.

What you are describing is a variable polarizing filter. Orion sells one for about $30 and I'm sure you can find one on the Anacortes site as well. The ones you can buy will be a lot more compact than one you would make using two filters (and will probably cost less).

You can adjust the amount of light coming into the eyepiece using a variable polarizing eyepiece from almost no filtering to essentially totally black. They're very useful when viewing the moon, but I don't find them that helpful for viewing planets (except perhaps Venus). Even though you can blacken out the image, NEVER use one for viewing the Sun.