Editing Talk:2484: H-alpha
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| − | + | ===Additional detail=== | |
A H(ydrogen)-Alpha filter is a special lens used for viewing the {{w|H-alpha|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). | A H(ydrogen)-Alpha filter is a special lens used for viewing the {{w|H-alpha|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). | ||
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::To be exact, in fact, it was the Helium Act of 1925 that banned export (in order to supply the domestic naval vessels of the time, so pro-America rather than anti-Nazi, especially as the Nazi movement wasn't much more than a niche concept in one of various competing factions in that era). The designer had even hoped to get an exception (double-layer the lift-bladders, to use some helium and some hydrogen), but never got that. And then in 1938 there was bartered a deal (having sworn off hydrogen entirely, due to May '37s event) to allow export "only for peaceful purposes", which may have only stopped due to the annexing of Austria (and well before the general "Nazis bad!" message had become the on the ground leftpondian zeitgeist). [[Special:Contributions/141.101.98.175|141.101.98.175]] 11:46, 4 October 2023 (UTC) | ::To be exact, in fact, it was the Helium Act of 1925 that banned export (in order to supply the domestic naval vessels of the time, so pro-America rather than anti-Nazi, especially as the Nazi movement wasn't much more than a niche concept in one of various competing factions in that era). The designer had even hoped to get an exception (double-layer the lift-bladders, to use some helium and some hydrogen), but never got that. And then in 1938 there was bartered a deal (having sworn off hydrogen entirely, due to May '37s event) to allow export "only for peaceful purposes", which may have only stopped due to the annexing of Austria (and well before the general "Nazis bad!" message had become the on the ground leftpondian zeitgeist). [[Special:Contributions/141.101.98.175|141.101.98.175]] 11:46, 4 October 2023 (UTC) | ||
| − | {{w|MetLife|Metropolitan Life Insurance Company}} (AKA MetLife) is an insurance company that licensed the Peanuts characters, In particular, Snoopy in their advertising. They featured the {{w|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. [[Special:Contributions/162.158.142.160|162.158.142.160]] 06:29, 3 July 2021 (UTC) Not the Red Baron | + | {{w|MetLife|Metropolitan Life Insurance Company}} (AKA MetLife) is an insurance company that licensed the Peanuts characters, In particular, Snoopy in their advertising. They featured the {{w|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. |
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| + | [[Special:Contributions/162.158.142.160|162.158.142.160]] 06:29, 3 July 2021 (UTC) Not the Red Baron | ||
Many nebulae contain excited hydrogen atoms emitting the H<sub>α</sub> wavelength, so a H<sub>α</sub> filter is useful for removing other light such as light pollution, making nebulae stand out in photographs. | Many nebulae contain excited hydrogen atoms emitting the H<sub>α</sub> wavelength, so a H<sub>α</sub> filter is useful for removing other light such as light pollution, making nebulae stand out in photographs. | ||
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In most cases when a sun filter is mentioned, it's probably a white-light filter that only reduces the light intensity. A H<sub>α</sub> filter is used to highlight the sun's chromosphere – the layer above the sun's apparent "surface", the photosphere. | In most cases when a sun filter is mentioned, it's probably a white-light filter that only reduces the light intensity. A H<sub>α</sub> 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. [[Special:Contributions/162.158.183.220|162.158.183.220]] 11:52, 3 July 2021 (UTC) | + | I'm not sure whether the same filters are actually used for photographing both the sun and nebulae. |
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| + | [[Special:Contributions/162.158.183.220|162.158.183.220]] 11:52, 3 July 2021 (UTC) | ||
I think someone should edit the summary to detail two points: One, that blimps are not the same as zeppelins. The latter has a rigid body and tanks of gas, rather than the former's balloon body. And two, airships such as the Hindenburg were never designed to be flown using hydrogen; it would have continued to use helium on that one fateful flight if it had not been for a trade embargo on Germany for the gas from its largest supplier, the United States. | I think someone should edit the summary to detail two points: One, that blimps are not the same as zeppelins. The latter has a rigid body and tanks of gas, rather than the former's balloon body. And two, airships such as the Hindenburg were never designed to be flown using hydrogen; it would have continued to use helium on that one fateful flight if it had not been for a trade embargo on Germany for the gas from its largest supplier, the United States. | ||
