Meade Series 4000 Photo-Visual Color Filter Set #3 (4 filters): #8 Light Yellow; #21 Orange; #38A Dark Blue; #56 Light Green.
#8 Light Yellow (83% transmission): is used in observing red and orange-colored phenomena in the belts of Jupiter and in enhancing the level of observable detail of small orange-red zonal features within the belts of the planet. It increases contrast of Martian maria. Can result in improved resolution of dusky detail on Uranus and Neptune in instruments 10" aperture and larger. Is a popular filter for the enhancement of lunar features, particularly in telescopes 8" aperture and smaller. #21
Orange (46% transmission): Reduces or blocks transmission of blue-green wavelengths. Use on Jupiter and Saturn to enhance detail in the belts and polar regions. Sharpens boundaries between yellow-orange area and blue-green regions on Mars, resulting in a darkening of edge-detail in the Martian maria. #38A Dark Blue (17% transmission): Is a popular filter for the study of Jupiter's disk, owing to the filter's strong rejection of orange and red wavelengths. It increases contrast between the reddish belt structures and enhances detail of the Red Spot. Also useful for the study of isolated phenomena, such as dust storms, on Mars, as well as the belt structure of Saturn. Increases contrast of subtle cloud markings on Venus. #56 Light-Green (24% transmission): Is excellent for the observation of Martian polar ice caps as well as yellow-tinted dust storms on the Martian surface. Increases contrast of the red and blue regions in Jupiter's atmosphere as well as in the cloud belts. Also useful for enhancing lunar detail.
The use of a Meade Series 4000 color filter can mean the difference between seeing small craterlets in the floor of Clavius on the Moon and not; it can mean the difference between seeing five or six whirls, festoons, and loops in Jupiter's north equatorial belt and seeing one or two; it can mean the difference between seeing the inner crépe ring of Saturn and not. Depending on atmospheric conditions on both the Earth and the planet being observed, the advantages of color filters can be anywhere from subtle to dramatic.
For increased contrast and resolution of the Moon and planets in visual or photographic applications color filters are an essential tool of the lunar and planetary observer. These color filters permit the observation and photography of surface detail that is often virtually invisible without filtration. Filters solve or greatly reduce the effects of two basic observing problems: (a) Irradiation is the blurring of a boundary between lighter and darker areas of the Moon or a planetary surface and can be caused either by the effects of highly contrasting light impacting the human eye or by the motion of the Earth’s atmosphere, through which the observation is being made. (b) Contrast is the separation of adjacent surface regions according to their color; for example, a light green area on Mars can become mixed in the eye with an adjacent light yellow area, to the effect that the combined area appears yellow-green, not separated into its component regions.
Meade Series 4000 filters are a large 26mm in clear aperture and are manufactured from the purest crown optical glass, dyed-in-the-mass (not “color coated”); there are no finer filters available for telescopic applications. Each filter glass is anti-reflection coated on both sides and is mounted in a machined aluminum cell with the Wratten No. of the filter marked on the side of the cell. Filters may be piggybacked, or stacked, to achieve selective filtration of the visual color spectrum. For visual applications, Series 4000 filters thread into the barrels of all Meade 1.25" eyepieces and into the barrels of virtually all other 1.25" eyepiece brands as well. The eyepiece with the attached filter can be placed in the eyepiece holder of a Schmidt-Cassegrain telescope or Meade ED Apochromatic Refractor for Tele-Extender eyepiece-projection photography of the Moon and planets. The filters also thread into the barrels of the Meade Camera Adapter (1.25") and Variable-Projection Camera Adapter. Each Series 4000 filter is packed in a foam-fitted plastic case for secure long-term storage.
|
