Today's APOD is fine, but in order to make sense of the 1970s we'll have to look at the full size version of the APOD:
As for where NGC
1977 is, I'll just take APOD Robot's words for it that it is below the Running Man!
NGC 1973 is illuminated by
HD 36958, a star of spectral class B3/B5 (according to Simbad). A star of these spectral classes produces a lot of blue light, but not enough UV light to ionize a red emission nebula, so it is perfect for lighting up a blue reflection nebula.
NGC 1975 is illuminated by by at least three stars, the brightest of which is HD 294262. Simbad calls its spectral class A E, which is very helpful. Not. Well, in spite of that confusing "A E", I'd say that this is also a B-type star, although cooler than the one lighting up NGC 1973. I'm sure you're all taking notes!
Let's look at the star that is the most important player here:
42 Orionis in the Running Man Nebula.
Image credit: Ngc 1535 of English Wikipedia.
42 Orionis is a star of spectral class B1V, which means it is just barely hot enough to ionize a faint red emission nebula. It also emits copious blue light to paint the surrounding "sky" blue. But the Running Man can thank the
wheezing UV light of 42 Ori for the dull red color of his (admittedly somewhat loose)
spandex suit.
Finally, yes, let's grab this moment to think a bit more about the 1970s, shall we?
Click to play embedded YouTube video.
Mary Hopkin actually recorded the song in the video in 1968. That's close enough to the 1970s.
Ann
Today's APOD is fine, but in order to make sense of the 1970s we'll have to look at the full size version of the APOD:
[float=left][img3="Reflections on the 1970s.
Image Credit & Copyright: Daniel Stern"]https://apod.nasa.gov/apod/image/2302/NGC1975RunningMan_1024.jpg[/img3][/float][float=right][attachment=2]APOD 2 February 2023 detail annotated.png[/attachment][/float]
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As for where NGC [url=https://api.time.com/wp-content/uploads/2014/11/15502780.jpg?quality=85&w=280]1977[/url] is, I'll just take APOD Robot's words for it that it is below the Running Man! :D
NGC 1973 is illuminated by [url=http://simbad.cds.unistra.fr/simbad/sim-id?Ident=%40800753&Name=HD%20%2036958&submit=submit]HD 36958[/url], a star of spectral class B3/B5 (according to Simbad). A star of these spectral classes produces a lot of blue light, but not enough UV light to ionize a red emission nebula, so it is perfect for lighting up a blue reflection nebula.
NGC 1975 is illuminated by by at least three stars, the brightest of which is HD 294262. Simbad calls its spectral class A E, which is very helpful. Not. Well, in spite of that confusing "A E", I'd say that this is also a B-type star, although cooler than the one lighting up NGC 1973. I'm sure you're all taking notes! 😄
Let's look at the star that is the most important player here:
[float=left][attachment=1]42 Orionis in the Running Man Nebula Adam Block.png[/attachment][c][size=85][color=#0040FF]42 Orionis in the Running Man Nebula.
Image credit: Ngc 1535 of English Wikipedia.[/color][/size][/c][/float]
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42 Orionis is a star of spectral class B1V, which means it is just barely hot enough to ionize a faint red emission nebula. It also emits copious blue light to paint the surrounding "sky" blue. But the Running Man can thank the [url=https://www.youtube.com/watch?v=T4qNgi4Vrvo]wheezing[/url] UV light of 42 Ori for the dull red color of his (admittedly somewhat loose) [url=https://i.pinimg.com/originals/da/78/be/da78be9d285129b59a1b7a472d1bef3a.jpg]spandex suit[/url].
Finally, yes, let's grab this moment to think a bit more about the 1970s, shall we? :D
[float=left][attachment=0]Pictures of the 1970s.png[/attachment][/float][float=right][youtube]https://www.youtube.com/watch?v=y3KEhWTnWvE[/youtube][/float]
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Mary Hopkin actually recorded the song in the video in 1968. That's close enough to the 1970s.
Ann