Baader Planetarium 2" Moon & Skyglow Filter (contrast filter, excellent for Jupiter and Mars).

This filter is designed to transmit the maximum amount of incoming light, while suppressing skyglow due to artificial lighting and background glow when the Moon is up. The filter material is a special Neodymium glass that effectively filters out selective wavelengths of low-pressure sodium and other manmade sources. Although it is not a nebula filter, it enhances the views of deep-sky galaxies and nebulae by increasing the contrast of these objects against the background sky. While nebula filters transmit only a few select wavelengths corresponding to various atomic lines, this filter transmits a large portion of the continuous spectrum, while blocking a few select lines of the more common manmade light.

This filter can also be used for lunar/planetary viewing. It increases planetary contrast and works especially well on Jupiter and Mars to help bring out subtle detail.

The Moon & Skyglow filters are polished optically flat to maximize optical quality. Therefore, it can be used in front of CCD cameras or high power eyepieces without introducing optical defects.