An eyepiece filter can bring out detail in an object, assist with astrophotography, help reduce the effects of light pollution. The type of filter to used depends on what you are observing.
Types of Filters for Astronomical Viewing
Moon Filter
The moon is a beautiful sight even in a small telescope, however the moon is very bright and using a moon filter can save your night vision. A moon filter can also bring out contrast making maintains and craters sharper. Moon filters reduce irradiation, which is the distortion at the boundary between light and dark areas, such as along the lunar terminator.
Polarizing
Another popular filter that cab be used on the moon. This filter is also helpful for splitting binary stars by reducing glare and diffraction around the brighter star of the binary pair. On moon and planets it is invaluable for reducing irradiation and glare.
Broadband Light Pollution Filter
A light pollution filter is a filter that is designed to eliminate the wavelengths os light that are common to man made mercury vapor, sodium and other lights. In doing so the also diminish the light from stars and and star clusters. The light from some nebulae are at a different wavelength and therefore are able to pass through the filter. Therefore these filters are best used when looking at these nebulae. Of the filters you can use to enhance nebulae this is the least effective.
UHC
These filters block out the most sky glow and better enhance emission and planetary nebula the than a broadband filter..
Oxygen III
The Oxygen III filter does a better job enhancing planetary nebula and some emission nebula then the UHC. This is by far the best filter for looking at planetary nebulae. In some cases a UHC filter may do a better job on emission nebulae.
Hydrogen-Beta
The H-beta eyepiece filter enhances only a few emission such as the California and IC 434 making the horsehead easier to see. It will also enhance some very faint emission nebula.
This is our list of telescope eyepiece filters. Eyepiece filters can bring out detail in an object, assist with astrophotography, help reduce the effects of light pollution. The type of filter to used depends on what you are observing.