Starship Asterisk*

Ann wrote:

Click to view full size image

M42 and M43. Photo: Sid Leach.

There has been a mistake in the caption of today's APOD. The caption describes today's APOD as if it showed us M42, the great Orion Nebula. But what we are really seeing is M43.

By the way, nice picture. When I saw it I thought, how nice to see M43 instead of M42 highlighted for a change!

Ann

BDanielMayfield wrote:

I hope this lovely image of M43 is retained and the Explanation is replaced, instead of just plugging in another M42 shot.

Bruce

(Do) you see how there’s a dark dust lane dividing the great nebula into two parts, one of which is about ten times larger than the other? That smaller part is what Messier 43, or De Mairan’s nebula, actually is!
...
The brightest star in there is a young, hot and ultra-massive blue star, most probably destined to go supernova in only a few million years.
...
A closer inspection reveals that there are actually a great many young stars that have formed inside...
...
Furthermore, what’s incredibly interesting is that the bright, central star would have passed within just 109 light-years of us some 9 million years ago based on its current orbit, making it one of the brightest stars in our sky. But it probably didn’t exist that long ago, having formed much more recently than that!

Whereas the full, main Orion Nebula has many stars illuminating it, there’s only one primary star giving rise to this one, hence it’s often known as either the little, small or miniature Orion Nebula.

https://en.wikipedia.org/wiki/Jean-Jacques_d%27Ortous_de_Mairan wrote:

---

<<Jean-Jacques d'Ortous de Mairan (26 November 1678 – 20 February 1771) was a French geophysicist, astronomer and most notably, chronobiologist, was born in the town of Béziers on 26 November 1678.

In 1719, De Mairan discussed the varying obliquity of light that causes cold in winter and heat in summer. He postulated that the sun's heating effect was related to the square of the sine of its elevation. He neglected the effects of atmosphere, admitting that he did not know how much the sun's heat would be absorbed by it. Two and a half years later, he presented a paper to the Academie Royale des Sciences in Paris: "Problem: the ratio of two degrees or quantities of sunlight seen through the atmosphere at two different known angular elevations being given, to find what part of the absolute light of the sun is intercepted by the atmosphere at any desired elevation." In this paper, de Mairan made a hypothesis based on mere observations, supposing that the ratio had been measured, even though it had not. The significance of de Mairan's work, although incorrect, led his protégé, Pierre Bouguer, to invent the photometer.

In 1729, de Mairan constructed an experiment showing the existence of a circadian rhythm in plants.

In 1731, he also observed "De Mairan's Nebula" around a star near the Orion nebula.
This was later designated M43 by Charles Messier.>>

Ann wrote:There has been a mistake in the caption of today's APOD. The caption describes today's APOD as if it showed us M42, the great Orion Nebula. But what we are really seeing is M43.

Chris Peterson wrote:

Ann wrote:There has been a mistake in the caption of today's APOD. The caption describes today's APOD as if it showed us M42, the great Orion Nebula. But what we are really seeing is M43.

Well, to be fair, what is usually called "The Great Nebula in Orion" or just "The Orion Nebula" conventionally includes both M42 and M43. So it's a bit confusing when we see just a small area that is difficult to place in context.

Ann wrote:I believe that the central star of M43 is Nu Orionis or HD 37061, a star of spectral class O9V.

Ann

Ann wrote:

Chris Peterson wrote:

Ann wrote:There has been a mistake in the caption of today's APOD. The caption describes today's APOD as if it showed us M42, the great Orion Nebula. But what we are really seeing is M43.

Well, to be fair, what is usually called "The Great Nebula in Orion" or just "The Orion Nebula" conventionally includes both M42 and M43. So it's a bit confusing when we see just a small area that is difficult to place in context.

The caption does mention M42, but not M43. That is not okay for this image.

Ann wrote:The caption describes today's APOD as if it showed us M42, the great Orion Nebula. But what we are really seeing is M43.

BDanielMayfield wrote:

Ann wrote:I believe that the central star of M43 is Nu Orionis or HD 37061, a star of spectral class O9V.

Ann

Now look at who's Lost. Nu Orionis is in the northern part of Orion.

Ann wrote:

BDanielMayfield wrote:

Ann wrote:
I believe that the central star of M43 is Nu Orionis or HD 37061, a star of spectral class O9V.

Now look at who's Lost. Nu Orionis is in the northern part of Orion.

Oh, sorry! You're right! I meant NU Orionis, not Nu Orionis!

• Nu titta på vem som hittas

neufer wrote:

Ann wrote:

BDanielMayfield wrote: Now look at who's Lost. Nu Orionis is in the northern part of Orion.

Oh, sorry! You're right! I meant NU Orionis, not Nu Orionis!

• Nu titta på vem som hittas

• Gunnar 'Nu' Hansen

Ann wrote:A: What's the meaning of life, the universe, everything and the APOD?

B: Mmm...42?

A: Mmmm...43!!!

(My third post in a row. Sorry. I couldn't resist.)

Ann

BobStein-VisiBone wrote:Huh, I do believe that's a mirror image.

Chris Peterson wrote:

BobStein-VisiBone wrote:Huh, I do believe that's a mirror image.

Yes, it's mirrored vertically- north down, east left. Somewhat unfortunate, given that there was no good reason to break convention here, but it is what it is.