About Filter
✅ Filters used in astronomy Visible light is emitted in a range of about 380 to 780 nanometres: from the short wavelength blue-violet end to the long wavelength red end. When observing a particular astronomical object in a telescope, you can often improve contrast by the use of an appropriate filter. The filter achieves this by blocking certain regions of the visible spectrum and letting others through. There are filters in all conceivable colours that are often used for Lunar and planetary observing. You can make specific details on the surface of planets stand out more via their use. Moon filter |
A neutral, grey or moon filter is used to lessen the intensity of bright moonlight and to slightly increase contrast. Anyone who has ever been to an observatory and looked at the Moon through a large telescope without a filter will vividly remember the experience and know why this filter is so important. Observing the moon without a filter will not cause any damage, but it is so bright that it really dazzles you. If you then turn away from the telescope and look into the darkness you will often still have a ghostly afterimage of the moon in the eye you observed with. Although this afterimage will gradually fade, it is still very irritating. Of course these filters are available in different light reduction levels. They range from a light transmittance of about 8% up to 50%. The filters with a high transmittance are suitable for the smaller telescopes and those with a low transmittance are suitable for larger telescopes. |
Astromania 1.25" Narrowband Nebula Red Filter Astromania 2" Narrowband Nebula Red Filter |