One of the most useful accessories to have when observing the Moon and planets are eyepiece filters. Although the use of a coloured filter can “re-colour” your view, the end result is improved image definition. A filter can enhance surface details of a planet (e.g. Mars) or atmospheric cloud structures (e.g. around Jupiter).
Celestron’s new Celestron Lunar and Planetary four colour filter set (due in stock soon) is an ideal package for those starting on their voyage of planetary (observational) discovery. These filters fit any 1.25″ eyepiece by simply screwing them into the end of the eyepiece barrel. Alternatively, if your telescope uses a 1.25″ push-fit diagonal, you can screw the filter in the end of the diagonal’s nosepiece which means you don’t have to keep swapping the filter when using different eyepieces (which keeps them safe and clean too).
Each of these Celestron 1.25” filters has a 26 mm clear aperture. The filter glass is mounted in a black anodised aluminium cell that is threaded on both sides which allows you to attach different filters together (called stacking) to create a new “custom colour” or affect the light transmission to your eye. Each filter has special coatings to protect against reflections, ghosting, and scratches.
The set includes the following filters:
- 12 Deep Yellow: It will help improve the contrast of Lunar features. It will help with the observation of clouds and the polar ice caps on Mars, the equatorial belts on Jupiter and Saturn.
- 21 Orange – Will sharpen the boundaries on the plains of Mars. For Jupiter and Saturn, it will enhance detail in the atmospheric belts and polar regions.
- 80A Blue – It will enhances the contrast of the Moon. For Mars, this blue filter will help show its atmospheric clouds and darken its red coloured features. It will also help enhance views of Jupiter’s cloud belts and Saturn’s polar regions.
- ND-96-0.3 Neutral Density – This 50% transmission filter can be used on its own, or alongside the other filters (in a stack), to dim the brightness of the Moon and planets. A neutral density filter is also useful when wanting to observe and “split” double stars. Being a neutral coloured density filter decreases the image brightness without affecting the colour of an object.
The number given above, before the filter colour, is called a Wratten number, which sometimes includes a letter (e.g. 1A), and is a system for labelling filters.
Celestron provide a useful plastic case to keep your filters safe when not in use or when you are out in the field.
If you would like to purchase the filter set from ourselves and would like to know when they come into stock, if you follow the link to the Celestron 1.25″ Lunar and Planetary Filter Set you will see that there is an “Item out of stock” notification on the right hand side. Here you can enter your email address so you can be notified as soon as stock arrives – see the image below.