The Opticstar 1.25” filters have 26mm of clear aperture, and are mounted in a black anodized aluminium cell that is threaded on the front and back. As such it is possible to stack filters to create different hues. The filters are optically coated to combat reflections and ghosting, and also to protect the filters from scratches.
The filters will screw in the front of 1.25" eyepieces and diagonals that are threaded to accept filters, most modern eyepieces and diagonals are threaded for this purpose. They can also be used with 1.25" type filter-wheels.
There are many filters available and it is difficult to decide which filters would prove to be more useful. The Opticstar Planetary Filter Set consists of four planetary filters that have been carefully selected to maximise their coverage and usefulness.
#12 Deep Yellow
The #12 deep-yellow filter will brighten desert regions and darken ‘blue’ and ‘brown’ features on the surface of Mars thus increasing contrast. It will darken the blue festoons near the North Equatorial belts and Equatorial zone on Jupiter and increase contrast on the blue features of Saturn.
It can also be used on the Moon, Jupiter and Venus with an achromatic telescope as it will mask blue and violet fringes thus reducing the visible effects of colour aberration present in the telescope’s optics.
The #21 orange filter significantly reduces transmission of blue-green wavelengths. It will enhance detail in the belts and Polar regions of Jupiter and Saturn. Sharpens boundaries between yellow/orange areas and blue-green regions on Mars; resulting in a darkening of edge-detail in the Maria.
#56 Light Green
The #56 light-green filter increases contrast of the red and blue regions in Jupiter's atmosphere and brings out the great Red Spot and cloud bands. It is very well suited for the observation of Martian polar ice caps and yellow-tinted dust storms on the surface of the planet. This filter can also be used to enhance Saturn's rings.
The #80A blue filter can bring out detail in the belts and oval clouds of Jupiter, it will also increase contrast within the bright zones on the planet and sharpen boundaries of faint cloud currents.
The filter will darken reddish features on Mars and show atmospheric clouds over the planet’s surface, limb hazes and also enhance the polar caps. It may also allow you to see high clouds near the limb of Mars. In daytime, it will darken the blue sky background making it easier to observe Venus. When used with a large telescope at high powers you may also be able to see some detail in the clouds of Venus.
Using planetary filters
In general colour filters help to increase the sharpness and detail levels in the atmospheres and surfaces on Jupiter, Saturn, Venus, Mars, Uranus and Neptune, as well as on the surface of the Moon. When you first use colour filters you will notice some difference but with practice you will see a lot more detail, especially at higher magnifications.
Colour filters can also be used in conjunction with single Polarising filters to increase contrast on the Moon and planets. They are also useful for splitting close double stars where the bright primary star overwhelms its companion. The Polarising filter diminishes the glare of the primary to an extent so that the secondary becomes visible.
Carries full one year UK warranty.
Opticstar Filter Set A.