This guide combines three short posts from this site: the Meade 07530 Series 4000 Colour Filter Set No. 1, the Meade Series 4000 ND96 Moon filter, and a SolarLite solar filter. Together they cover the three filter types most beginners ask about: colour filters for planets, a Moon filter for glare, and solar filters for safely viewing the Sun.
What does a telescope filter do?
Most eyepiece filters are small pieces of glass in a threaded cell that screws into the bottom of an eyepiece barrel. Meade UK says its Series 4000 filters are threaded for and compatible with all Meade Series 4000 and Series 5000 eyepieces, and fit 1.25-inch (26 mm) barrels. Each filter weighs about 3 grams and measures about 30 mm across.
Meade says colour filters permit observation and photography of planetary surface detail that is often virtually invisible without filtration. You can use them one at a time or stacked together.
Meade Series 4000 Colour Filter Set No. 1 (07530)
Meade UK describes the filters as made from optical glass with the colour dyed into the glass rather than applied as a coating, and anti-reflection coated on both sides. The set contains four filters:
- #12 Yellow (74% transmission): contrasts strongly with blue features on Jupiter and Saturn while enhancing red and orange features. Useful for increasing the contrast of lunar features.
- #23A Light Red (25% transmission): strong contrast for marginal blue-green detail, mainly on Jupiter, Saturn and Mars. It also increases the contrast between Mercury and a bright blue sky in daylight or twilight.
- #58 Green (24% transmission): brings out belts and structure on Jupiter and Saturn, strongly increases the contrast of Mars’ polar ice caps, and helps with difficult atmospheric features on Venus.
- #80A Blue (30% transmission): a popular filter for Jupiter and Saturn, enhancing rills and festoons in Jupiter’s cloud belts and details of the Red Spot, and bringing out detail in Saturn’s belts. Meade also calls it very useful as a contrast-enhancing lunar filter.
The transmission figure tells you how much light gets through. The yellow filter passes about three quarters of the light, while the red, green and blue filters pass about a quarter, so the view gets much dimmer.
The ND96 Moon filter (07531)
The Moon can be dazzlingly bright in a telescope. Meade UK describes the Series 4000 ND96 as a neutral density filter that transmits light uniformly across the entire visual spectrum, so it dims the view without adding a colour. It transmits 13% of the light. Meade says it is an excellent filter for reducing glare when observing the Moon with larger telescopes, and can also help split close double stars where one star is much brighter than the other.
Solar filters: always on the front
Colour and Moon filters are never safe for looking at the Sun. The American Astronomical Society (AAS) says that, with one exception, it is never safe to look directly at the Sun through a telescope, binoculars or camera lens without a solar filter. The exception is totality, the brief total phase of a total solar eclipse.
The AAS explains that solar filters do two jobs: they protect the instrument from intense sunlight and heat, and they stop you accidentally looking at the Sun through unfiltered optics. Its key rules:
- Front only: the solar filter must be attached to the front of your telescope, binoculars or camera lens, so the Sun’s light and heat are kept out of the optics.
- Secure fit: attach the filter so it won’t pop off if the instrument is bumped or the wind gusts.
- Cover the finder: cap, remove or filter any small finderscope too.
- Avoid eyepiece solar filters: the AAS says solar filters supplied with inexpensive telescopes that thread into the eyepiece are dangerous, because concentrated sunlight can burn right through them.
- No eclipse glasses behind optics: looking through unfiltered optics while wearing eclipse viewers is extremely dangerous.
The AAS lists three types of solar filter: metal on glass (usually the most durable and expensive), aluminised polyester film, and black polymer. Some show the Sun white, others give it a yellow, orange or bluish tint. The AAS says all are effective, so choose the type that suits your preference.
Corrections to the original posts
- The original colour-filter post said the yellow filter is ideal for 6-inch and larger telescopes and the green filter for 8-inch and larger. Meade UK’s description gives no such aperture limits, so we removed them. It also said the filters work with “almost all other brands”; Meade only states compatibility with its Series 4000 and 5000 eyepieces.
- The ND96 post recommended telescopes of 4 inches and larger. Meade UK says “larger telescopes” without a figure.
- The SolarLite post made claims we could not verify (never developing pinholes, a 15-year guarantee, strength compared with other films). These were removed. The original listing described its film as a black polymer, one of the three solar filter types the AAS lists.
Quick summary
- Colour filters boost contrast on the Moon and planets.
- The ND96 Moon filter cuts glare to 13% transmission without adding colour.
- Solar filters must cover the front of the telescope and finder, never the eyepiece.
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