Altair 2nm G-Band Solar Contrast Filter

The contrast is improved so that the faculae stand out better from the photosphere and the umbral and penumbral features of a sunspot are more recognisable. The structural details within sunspots and their immediate surroundings are better recognisable. The convection cells of the photosphere, also known as "granulation", are also enhanced.

This filter also presents an interesting challenge for solar observers: Apart from contrast enhancement, the G-band filter can also make the elusive "bright spots" between the sun's convection cells visible with a reflector of 250 mm aperture or more. These challenging structures are not often imaged by amateurs, but are now possible. The corresponding solar film ND3.8 should be available. Full-mirror telescopes with an open tube, such as Newtonian telescopes and classic Cassegrains, would be the ideal instruments to try this with. Talk to us about large customised solar filters.

Please note: This filter is intended for use with a safe, professional brightness reduction filter such as EMC filter with ND3.8 (*) (reflectors and refractors) or Herschel wedge (refractors only).