Talk:2484: H-alpha

I think the first company that got really mad was Goodyear, because they're famous for using blimps.

- unsigned comment

Additional detail

A H(ydrogen)-Alpha filter is a special lens used for viewing the Hydrogen-Alpha wavelength of light through telescopic or photographic devices. It works by filtering out all wavelengths of light except the red spectral line associated with hydrogen. This is commonly used to see shape and structure of objects that emit said light (namely, our own sun, and various nebulae as mentioned in the text).

Many earlier designs for airships (including the ill-fated Hindenburg) used (highly flammable) hydrogen gas for lift due to both its lower cost and higher availability. After the Hindenburg disaster designers switched exclusively to helium or heated air for lift.

Metropolitan Life Insurance Company (AKA MetLife) is an insurance company that licensed the Peanuts characters, In particular, Snoopy in their advertising. They featured the Snoopy character in his alter-ego role of World War I Fighter Ace (which frequently fought with the Red Baron in the Charles Schulz comics) in both print and television ads between 1985 and 2016, and most notably pictured on some of their advertising blimps.

162.158.142.160 06:29, 3 July 2021 (UTC) Not the Red Baron

Many nebulae contain excited hydrogen atoms emitting the H_α wavelength, so a H_α filter is useful for removing other light such as light pollution, making nebulae stand out in photographs.

In most cases when a sun filter is mentioned, it's probably a white-light filter that only reduces the light intensity. A H_α filter is used to highlight the sun's chromosphere – the layer above the sun's apparent "surface", the photosphere.

I'm not sure whether the same filters are actually used for photographing both the sun and nebulae.

162.158.183.220 11:52, 3 July 2021 (UTC)