Altair 2 nm G-Band Solar Contrast Filter - 1.25" 430.3 nm

Altair 2 nm G-Band Solar Contrast Filter - 1.25" 430.3 nm

The Altair G-Band 2 nm Solar Filter brings out finer details in the solar photosphere.

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

This filter also presents an interesting challenge for solar observers: Apart from improving contrast, the G-band filter can also make the elusive bright spots between the convection cells visible with a reflector of 250 mm aperture or more. These challenging structures are not often imaged by amateurs, but this is now possible. The required solar film ND3.8 must be installed. Reflector telescopes with open tubes, such as Newtonian telescopes and classic Cassegrains, would be the ideal instruments to attempt this. Talk to us about large custom solar filters.

Please note: This filter is intended for use with a safe, professional brightness reduction filter such as filters with ND3.8(reflectors and refractors) or Herschel wedge (refractors only).
Please contact us if you need help!

Each filter is provided with a high-resolution spectrographic chart, which is only valid for the serial number of the respective filter.

IMPORTANT SAFETY NOTE: DO NOT USE THIS FILTER FOR DIRECT OBSERVATION OF THE SUN!
Must be used together with a professional solar filter film or glass or a Herschel wedge with max. 0.024% transmission IN FRONT OF f this filter. For reflector telescopes, we recommend installing a solar film filter on the front of the telescope and then screwing the filter into a filter holder, camera or eyepiece. For refractors, the G-band filter should be placed directly in front of the camera or eyepiece, with a Herschel wedge placed in front of it. Do not use this filter without a suitable solar pre-filter, as it can permanently damage your eyes or your camera!

UV, IR and visual wavelengths are blocked, and only an ultra-narrow 2 nm FHWM blue band at 430.3 nm is transmitted to your camera. This significantly increases the contrast of solar features when observing or imaging with a color or mono camera, revealing more detail in the solar photosphere.

A mono camera is recommended, e.g. the super-fast Altair Hypercam 174M or the ultra-fast Altair GPCAM3 287M Mono USB3 camera (also known as "Babyshark").

NOTE
Do not place the filter in front of the Herschel wedge as it will melt. It should be placed directly in front of the camera and can be screwed directly into the Altair GPCAM or any other 1.25" nosepiece.