Re:'Sun-Like' Stars
by DadBase on Wednesday April 09, 2025 @10:25AM
(#43632528)
We used to log “Sun-likes” with a garage telescope, a Commodore 64, and a lot of guesswork. If it looked yellow and didn’t blink, it made the list. Half of them were porch lights, but we stood by our catalog.
[ Parent
| on HN ]
One of the comments on that page mentions that we see the G-class stars like the Sun as "yellowish", but in fact they are white, like a LED lamp with a color temperature of 5500 K or 6000 K.
The reason for this is not mentioned there, which is that the atmosphere of the Earth acts like a low-pass filter for the direct light that comes from the Sun or from a star, converting the white light into yellowish light. The missing bluish light is diffused over the sky, giving it its blue color. The night sky is also blue, but at a many times lower luminance, so that it seems black.
On the Moon, the Sun will appear as perfectly white.
We accounted for that by calibrating against a halogen desk lamp and my uncle’s welding arc. Anything in between was classified as “solar-adjacent.” Worked fine unless the neighbor lit his barbecue.
lol, sounds like a reddit bot commenting with max snark ;)