APOD: Deep Nebulas: From Seagull to California (2024 Jan 23)

[APOD Robot]

Deep Nebulas: From Seagull to California

Explanation: How well do you know the night sky? OK, but how well can you identify famous sky objects in a very deep image? Either way, here is a test: see if you can find some well-known night-sky icons in a deep image filled with faint nebulosity. This image contains the Pleiades star cluster, Barnard's Loop, Horsehead Nebula, Orion Nebula, Rosette Nebula, Cone Nebula, Rigel, Jellyfish Nebula, Monkey Head Nebula, Flaming Star Nebula, Tadpole Nebula, Aldebaran, Simeis 147, Seagull Nebula and the California Nebula. To find their real locations, here is an annotated image version. The reason this task might be difficult is similar to the reason it is initially hard to identify familiar constellations in a very dark sky: the tapestry of our night sky has an extremely deep hidden complexity. The featured composite reveals some of this complexity in a mosaic of 28 images taken over 800 hours from dark skies over Arizona, USA.

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[Ann]

I'd love to comment on this image, but I have no time this morning! (Yes, it's morning here.)

But the annotated picture is really great, and I must commend the APOD editors for finding so many APODs highlighting the individual nebulas and clusters in this image! Go check out the links and compare them with the annotated image. Note: If you have trouble finding the Seagull Nebula, it's because it is very very tiny just peeking out of the lower left corner.

APOD 23 January 2024 detail.png (45.11 KiB) Viewed 1790 times

What, couldn't you find it?

Okay, gotta leave! Be back later, I hope.

Ann

[LeonidQ]

Found a typo in annotations: AldebEran.

[mister T]

Wow! Space is really big!

[Roy]

As the British might say, what’s all this in aid of, then? Would you be able to identify them if a mosaic of 28 bearded Civil War generals were posted? If Grant, Lee, Sherman, and Forrest were not there, most people would have no clue.

[Ann]

Okay! This is a great APOD, but at the same time, it's really hard to make head or tails of some of the deep-sky objects here!

Deep Nebulas: From Seagull to California. Image Credit & Copyright: Alistair Symon

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One thing that I absolutely love about this APOD is how it shows us that the nebulosities here seem to be connected and form huge shells!

But I frankly can't identify all the nebulas here - in fact, not by a long shot! But let's take a look at some of the stars and nebulas and see what I think they are!

As you can see, I tried to identify only parts of the APOD, and I wasn't able to identify all the nebulas at all. But let's look at some of the sights here:

IC 2162. Isn't this one funny? It looks like a pair of red alien eyes in front of, perhaps, a red skull or something! Credit: Bernhard Hubl.

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Sharpless 261. The annotated APOD calls it Sh2-262, but that's another nebula. Sharpless 261 looks like a half-closed eye, doesn't it? Credit: Steve Milne.

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This half-closed eye looks like nebula Sharpless 261, doesn't it?

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I like this picture, because it shows us where things are located relative to one another. The Jellyfish Nebula is at upper center, just above orange star Eta Geminorum. Blue reflection nebula is to the upper right of the Jellyfish Nebula, and orange Mu Geminorum is at top, next to another red nebula. At far left is the Monkeyhead Nebula, and at far right is star cluster M35. To the lower left of M35, you can see small whitish blob. That's rich old cluster NGC 2158. In this picture, north is to the right. Credit: Scott Rosen.

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I love pictures that show the connection between the Rosette Nebula and the Cone Nebula and Christmas Tree Cluster. In this picture, the Rosette Nebula is at center right, and the Cone Nebula and Christmas Tree Cluster at center left. Credit: Ahmed Waddah.

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I love this picture! The large red shape is the Seagull Nebula, looking most impressive indeed, and the small blue 'insect' or 'butterfly' is Thor's Helmet! Credit: Ali Alobaidly

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Not quite like this but something like this!

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Let's talk a little about the what the APOD really reveals to us. The photographer, Alistair Symon, is a master at bringing out even very faint red hydrogen alpha emission (even if it looks yellow in today's APOD). That's why we see so many nebulas in this APOD. Many of the nebulas here are so faint that they are very rarely photographed.

But Alistair Symon is showing us something else too, namely that long stretches of the Milky Way are not home to visible red nebulas or visible star formation. Take a look at this picture of the northern Milky Way:

In this picture, red hydrogen alpha is indeed shown as red. At far left you can see NGC 7822. To the right of NGC 7822 are many nebulas in Cepheus, among them IC 1396. Then there is a black 'gap' and after that we have the North America Nebula and the Veil Nebula among others. 'Below' the band of the Milky Way in the Lacerta nebula. But please note the long stretch of Milky Way that does not contain any red nebulas at all! At far right, though, you can spot some tiny nebulas in Serpens and Sagittarius, among them the Lagoon Nebula. Credit: Alistair Symon.

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What we can learn from this is that, while dust seems to be necessary to create the right conditions for star formation in the nearby universe, the presence of dust does not guarantee the presence of star formation at all. Long dust lanes can indeed be "sterile":

AM 1316-241 is a pair of overlapping galaxies. one arm of the spiral galaxy at left is lit from behind by the light from from the elliptical galaxy at right. Note the long stretch of arm that contains dust only and no star clusters or nebulas at all. Credit: NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and W. Keel (University of Alabama, Tuscaloosa)

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There is more than meets the eye in the parts of the Milky Way that are rich in gas and dust. But there are also parts of the Milky Way that appear as "barren" as a desert, or as barren as a dusty but non-starforming elliptical galaxy. Like NGC 1316.

Elliptical galaxy NGC 1316. There is dust here, but no young star clusters or nebulas. The gas and dust in NGC 1316 is 'sterile'. Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

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So to summarize, galaxies are mysterious. Sometimes they rejuvenate themselves by birthing new stars, and sometimes they don't.

Ah yes, sometimes things happen and sometimes they don't. Completely off topic, here is a bonus video.

Click to play embedded YouTube video.

Ann

[C0ppert0p]

In answer to the gentleman who wondered why.
Most of the people who look at APOD are interested in what's up there; the names of Nebulae and stars and what it would all look like, if you have eyes the size of dinner plates; could keep them open for a few hundred hours hours; see in specific transmission lines; collect photons with your retina; etc

[Rauf]

Found a typo in annotations: AldebEran.

But AldebAran is the right spelling..

The traditional name Aldebaran derives from the Arabic al Dabarān (الدبران), meaning 'the follower', because it seems to follow the Pleiades. In 2016, the International Astronomical Union Working Group on Star Names (WGSN) approved the proper name Aldebaran for this star.

I think it's pronounced Addabaran

[Ann]

Found a typo in annotations: AldebEran.

But AldebAran is the right spelling..

The traditional name Aldebaran derives from the Arabic al Dabarān (الدبران), meaning 'the follower', because it seems to follow the Pleiades. In 2016, the International Astronomical Union Working Group on Star Names (WGSN) approved the proper name Aldebaran for this star.

I think it's pronounced Addabaran

Addaboy, Addabaran!

Ann