Filters Filter Orange #21 1.25"

Using colour filters for planetary observing requires practical experience and a large telescope aperture (the darker the filter, the more light the optics should let in). However, the orange filter can be used unrestrictedly by beginners. It brings out dark structures on Mars and increases contrast when viewing Venus at twilight. Alongside a Moon filter, an orange filter should always be readily available in your accessories bag.

(Stefan Taube)