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There are several specifics that one should remember regarding the use of filters:

First, filters lighten colors like themselves and darken their opposites, thus increasing contrast.

Second, filters can improve seeing conditions by isolating certain wavelengths of light. (varying
atmospheric conditions will distort some wavelengths more than others.)

Third, filters reduce the intense brightness that the big four, Mars, Venus, Jupiter, and Saturn exhibit.

The following rules apply 95% of the time while observing Mars:

Violet light (W-47) generally reveals the upper most atmospherics of Mars.  It should be mentioned that on unpredictable occasions the atmosphere can become quite transparent.  These moments of being able to clearly discern certain areas or even the entire globe's surface features is coined "the blue clearing".  These "blue  clearings" are best seen  with violet light (W-47).  Of course Venus's cloud features are best observed as well in Violet and Ultraviolet.  See  the June 1999 issue of Sky & Telescope.

The blues, (W-38, W-80, W-83 in smaller scopes) reveal mid-level clouds. During the past week, Mars has been displaying a plethora of afternoon and evening orographic clouds in the vicinity of Olympus Mons and the Tharsis volcanic fields. One cannot miss this atmospheric fireworks. They are as bright and widespread as I can ever remember!  The worst part is, most amateurs have probably missed it because they don't use filters at all. In integrated light they probably see brighter areas along the evening terminator, but may dismiss them as nothing unusual. They  are spectacular in blue light.

Green light usually reveals bright ground fogs, haze and surface frost deposits as well as some surface detail.. The Arctic regions of Mars have been displaying these phenomena the last several weeks, changing almost hourly! These ground fogs and frost deposits make can deceive one into believing the Polar Cap is much larger and apparent than it really is. These areas also can show in the reds to a lesser degree.

The Reds and to a lesser degree the Yellows penetrate through the atmosphere of Mars to enhance the definition of surface details. Desert areas appear bright. Dust storms can appear bright as well.

The image of Mars alternating between red light and blue light demonstrates how blue emphasizes the atmospheric features while the red light enhances the surface features.

A Shuler ultra-violet filter with infra-red blocking characteristics was used for this image of Venus that clearly shows cloud top features. "Although the origin of the UV features remains a mystery to this day, it is generally believed that gaseous sulfur dioxide and chlorine, the latter produced by the photo-dissociation of hydrochloric acid in the upper cloud layers, are responsible.  Both of these substances strongly absorb short-wavelength radiation."  ( "Observing and Photographing the Solar System" by Dobbins, Parker, and Capen)

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