Assuming we are now using a quality instrument with sufficient aperture (e.g. 6-inch refractor or 8-inch reflector) for the detection of color upon the surface/atmosphere of a planet what are other factors that one must consider.
The altitude of the planet above the horizon is important in the accurate determination of color upon it's surface or atmosphere. A planet located less than 30 degrees above the horizon will be subject to the phenomena of prismatic dispersion. We all see this while observing a bright star close to the horizon as it shines erratically in many colors. Observing a planet less than 30 degrees will make color assesment very difficult while observing through a thicker layer of the Earth's atmosphere. Observing the planet as close as posssible to the zenith will make the assesment of color more acurate.
Assuming that all the factors listed above have been addressed then we arrive at the question of what material to use to depict the colors observed over the planet. Unfortunately the colors visible upon the planets do not always conform with colors such as "passion pink" or "aqua blue" as included in our selection of color pencils. The observer may decide to use pastels or watercolor to arrive at the observed color instead. This is a time consuming process at best and requires adequate illumination using a white light (versus a red light that we sometimes use to make our planetary observations). The fact that some planets have a rapid rate of rotation (e.g. Jupiter with a rotation rate of less than 10 hours) makes the accurate determination of color more difficult.
An objective way to get around the accurate determination of a color observed upon a planet is the use of a Pantone color scheme (first proposed by an ALPO member who I will later identify). This is a color swatch containing over 3,000 colors used by graphic designers (an example being http://www.misterart.com/store/view.cfm?store=001&group_id=2810< I am not compensated by this store in any way). It can be obtained at most art stores for approximately $60 to $70. An observer using a Pantone swatch (under white light) next to the instrument can determine that the Great Red Spot (GRS) of Jupiter appears closest in color to Pantone DS 97-3 C (http://www.colorguides.net/process_guides.html) rather than stating "orange-red." This is not an absolute requirement but instead a suggestion in arriving at objective color assesments.
I personally prefer to use Prismacolor color pencils for my planetary color renditions. If using the 72 color palette this will provide a rather complete selection of colors although some mixing of colors will be required. An artist's stump and kneaded eraser will be helpful as well.
I have given a lengthly explanation of what appears to be a simple question which in truth is far from being so.
Respectfully,
Carlos E. Hernandez
The altitude of the planet above the horizon is important in the accurate determination of color upon it's surface or atmosphere. A planet located less than 30 degrees above the horizon will be subject to the phenomena of prismatic dispersion. We all see this while observing a bright star close to the horizon as it shines erratically in many colors. Observing a planet less than 30 degrees will make color assesment very difficult while observing through a thicker layer of the Earth's atmosphere. Observing the planet as close as posssible to the zenith will make the assesment of color more acurate.
Assuming that all the factors listed above have been addressed then we arrive at the question of what material to use to depict the colors observed over the planet. Unfortunately the colors visible upon the planets do not always conform with colors such as "passion pink" or "aqua blue" as included in our selection of color pencils. The observer may decide to use pastels or watercolor to arrive at the observed color instead. This is a time consuming process at best and requires adequate illumination using a white light (versus a red light that we sometimes use to make our planetary observations). The fact that some planets have a rapid rate of rotation (e.g. Jupiter with a rotation rate of less than 10 hours) makes the accurate determination of color more difficult.
An objective way to get around the accurate determination of a color observed upon a planet is the use of a Pantone color scheme (first proposed by an ALPO member who I will later identify). This is a color swatch containing over 3,000 colors used by graphic designers (an example being http://www.misterart.com/store/view.cfm?store=001&group_id=2810< I am not compensated by this store in any way). It can be obtained at most art stores for approximately $60 to $70. An observer using a Pantone swatch (under white light) next to the instrument can determine that the Great Red Spot (GRS) of Jupiter appears closest in color to Pantone DS 97-3 C (http://www.colorguides.net/process_guides.html) rather than stating "orange-red." This is not an absolute requirement but instead a suggestion in arriving at objective color assesments.
I personally prefer to use Prismacolor color pencils for my planetary color renditions. If using the 72 color palette this will provide a rather complete selection of colors although some mixing of colors will be required. An artist's stump and kneaded eraser will be helpful as well.
I have given a lengthly explanation of what appears to be a simple question which in truth is far from being so.
Respectfully,
Carlos E. Hernandez
