||Best Filter for Viewing
|Stars & Star Clusters
ProStar OIII (light polluted
UHC (dark sky)
ProStar OIII (light polluted
UHC (dark sky)
|Faint Planetary Nebulae
||NGC 7293, Abell 33, Jones 1
||Veil, Rosette, N. American
OIII (light polluted sky)
UHC (dark sky)
|Extremely Faint Nebulae
The Deep-Sky Hydrogen-Beta , Oxygen III ,
and Ultra High Contrast Filters are the result of 20 years of steady design improvements,
and continue to deliver the highest performance of all anti-light pollution filters
obtainable today. The following information recommends which filter to use on which
celestial objects, and explains how filter transmissions differ.
WRATTEN COLOUR FILTERS
#8 Light Yellow (83%
transmission) Used to enhance detail in red and orange features in the belts of Jupiter.
Is useful for increasing mare contrast on Mars and improving disc resolution of Uranus and
Neptune with larger telescopes. Can be used to enhance lunar detail also.
#11 Yellow-Green (78% transmission) Excellent for bringing out surface
details on Jupiter.
Darkens the mare regions on Mars.
#12 Yellow (74% transmission) Enhances red and orange features of Jupiter
and Saturn, while blocking blue and green wavelengths. It also lightens red and orange
features on Mars, while reducing, the transmission of blue and green areas. This filter
increases the contrast between the two. Also enhances the blue clouds in the Martian
atmosphere. Can also be used to increase contrast in lunar features with telescopes of
150mm aperture and larger.
#21 Orange (46% transmission) Reduces transmission of blue and green
wavelengths, thus increasing the contrast between these areas and red or yellow or orange
areas. Works very well with Mars. Sharpens the boundaries between these areas on the
planet's surface and can sharpen the contrast in the belts of Jupiter also enhancing the
Great Red Spot. Has slightly more contrast than the Wratten #15.
#23A Light Red (25% transmission) A popular filter for use when observing
Mars, Jupiter, and Saturn. Due to the lower light transmission of this filter, it is best
used with telescopes larger than 130mm aperture. A red almost dark
orange filter, it performs many of the same functions as
the #21 and the #15 but with somewhat more contrast. Can be a useful filter for daylight
observations of Mercury and Venus. improving contrast between these planets and the pale
#25 Red (14% transmission) The #25 and #25A filter strongly blocks the
transmission of blue and green wavelengths which results in very sharply defined contrast
between the cloud formations and the lighter hue features of Jupiter. Also quite useful
for improving definition of the Martian polar ice caps and darker mare surface regions.
#38A Dark Blue (17%
transmission) Very good for use on Jupiter because it strongly rejects red and orange
wavelengths in the belts and in the Great Red Spot, thus increasing contrast. It works
well on Martian surface phenomena, like dust storms, and increases contrast in the rings
of Saturn. Most suitable for Venus given its low light transmission and readily increases
contrast of subtle cloud markings.
#47 Violet (3%
transmission) Strongly rejects red, yellow, and green wavelengths, making it suitable to
use on the Martian polar ice caps. It is the best filter for observations of Venus due to
its low light transmission and ability to enhance upper atmosphere phenomena. Also can be
used for enhancing lunar detail. Presents interesting views of Jupiter and its satellites.
#56 Light Green (53% transmission) Very good for observing Martian polar
ice caps and yellow tinted dust storms on the planet's surface. Also increases the
contrast of the red and blue regions in Jupiter's atmosphere and cloud belts.
#58 Green (24%
transmission) Strongly rejects red and blue wavelengths increasing their contrast on the
lighter regions of Jupiter's cloud tops. Useful for enhancing the cloud belts and polar
regions of Saturn. Great for increasing contrast in polar ice caps of Mars and does a
reasonable job at improving contrast of atmospheric features on Venus.
#80A Blue (30% transmission) A magnificent all-round filter. Perhaps the
best economical filter for studying planetary detail of Jupiter and Saturn. Enhances
contrast of festoons and other disturbances in Jupiter's cloud belts, along with detail of
the Great Red Spot. Works great with Saturn revealing terrific detail in its belts and
polar features. Can be useful for lunar observations.
#82A Light Blue (73% transmission) Another outstanding performer like the
#80A and works well with Jupiter, Mars, Saturn and the Moon. Its pale blue colour enhances
low contrast areas and avoids significant reduction of overall light level at the same
ND96 Neutral Density (0.9 density, 13% transmission) The neutral density
filter transmits light uniformly across the entire visible spectrum making it an excellent
tool for glare reduction and studying bright localised lunar surface regions around times
of full Moon. Suitable also to improve contrast when splitting difficult double stars.
Intended for viewing nebulae from light-polluted skies.
Blocks all mercury vapour and high & low pressure sodium vapour lamp light, neon lights
and airglow, while transmitting the rest of the visible spectrum.
The best all-around visual light pollution filter for use in urban skies.
This filter also provides high-contrast views of the Martian polar caps
Ultra High Contrast Filters
Baader and ProStar narrow band pass filter isolates the two doubly ionized oxygen lines (496
and 501nm) and the hydrogen-beta line (486nm) emitted by planetary and most emission
Provides superb views of the Orion, Lagoon, Swan and other extended nebulae.
The best all-around dark-sky nebular filter available.
Oxygen III Filters
Narrow band pass filter (11nm) isolates just the two doubly ionized oxygen lines (496nm
and 501nm) emitted by planetary and extremely faint nebulae.Produces near-photographic views of the Ring Neb, Dumbbell Neb and Orion Neb etc.
Extremely narrow bandpass filter isolating the hydrogen-beta line alone (486nm).Excellent for viewing the Horsehead, Cocoon and California Nebulae.
Often the only way to view certain nebulae and are best used under clear skies with large aperture
Narrow band filters here
TO WRATTEN FILTERS FOR PLANETARY VIEWING & IMAGING