The image quality is not quite as good as what you would get with a 12.5mm eyepiece by itself. But adding a barlow lens is an affordable way to effectively double the number of eyepieces in your collection. Eyepiece Filters Several different types of filters are available for use with telescope eyepieces. These filters generally work by blocking wavelengths of light that may be interfering with the object you are trying to view. Light pollution filters work by blocking the scattered light from mercury vapor lights and other terrestrial light sources.
Colored filters can both block unwanted wavelengths of light and enhance details in an object.
For example, observing the planet Mars through a red filter will increase the contrast of the image and make surface details easier to see. A yellow or blue filter will make the Martian polar ice caps more visible. Observing the planet Jupiter through a yellow, blue, or green filter will enhance the details in the cloud bands and make the famous red spot easier to see. These filters are not very expensive. You may want to consider investing in a set of 4 to 6 assorted color filters when your budget can handle it.