APOD: The Seagull Nebula (2023 Jan 19)

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APOD: The Seagull Nebula (2023 Jan 19)

Post by APOD Robot » Thu Jan 19, 2023 5:06 am

Image The Seagull Nebula

Explanation: A broad expanse of glowing gas and dust presents a bird-like visage to astronomers from planet Earth, suggesting its popular moniker - The Seagull Nebula. Using narrowband image data, this 3-panel mosaic of the cosmic bird covers a 2.5 degree swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation Canis Major. Likely part of a larger shell structure swept up by successive supernova explosions, the broad Seagull Nebula is cataloged as Sh2-296 and IC 2177. The prominent bluish arc below and right of center is a bow shock from runaway star FN Canis Majoris. This complex of gas and dust clouds with other stars of the Canis Majoris OB1 association spans over 200 light-years at the Seagull Nebula's estimated 3,800 light-year distance.

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Re: APOD: The Seagull Nebula (2023 Jan 19)

Post by Ann » Thu Jan 19, 2023 7:36 am

Today's APOD is a very fine picture, and it becomes jaw-droppingly impressive when you consider the full size of it: 34.07 MB!! I mean!! :shock: :o

I like the colors too, even though I'm often critical of the mapped color of narrow-band images. But in this case, the colors are soft and pleasant, and I like them.

Even so... With my penchant for blue hues, I love the gorgeous blue (really OIII blue-green) arc above great runaway star FN Canis Majoris. But I wish that the star itself had been more obviously blue. So I searched the internet for pictures of of the Seagull Nebula where FN CMa would look both blue and "arc-d", and I found this great image by Stephane Guisard and Thierry Demange:

Seagull Nebula and blue runaway star with arc Guisard and Demange.png
The Seagull Nebula in Hα+RVB with blue "arc-star".

The all-dominant color of emission nebulas like the Seagull Nebula is of course a palette of rosy-red shades of pink from ionized hydrogen. But narrowband images, which typically don't look red or pink at all, bring out interesting details that are really present in the nebulas, but are not very visible at all except in, yes, narrowband imagery.

Yes, but the lovely arc above FN CMa contains just a bit of Hα and lots of OIII with perhaps a bit of blue mixed into it from the star itself.

I highly recommend this page from Stephane Guisard and Thierry Demange, where you can see an all-Hα version of the Seagull Nebula, and a stunningly beautiful full field portrait of the Seagull floating on the updrafts of the cosmic seas!

Oh, and by the way. I can't resist calling your attention to this lovely portrait of the Seagull Nebula and Thor's Helmet by Martin Konrat in the Recent Submissions thread.

Oh wow. Suddenly we are not on the cosmic seas but in the jungle, where an exotic bird with stunning red plumage takes to its wings to escape the irritating blue insect that is fluttering about, ready to sting.

Finally, maybe the seagull in the Seagull Nebula isn't a seagull but a red parrot?

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Re: APOD: The Seagull Nebula (2023 Jan 19)

Post by MelvzLuster » Thu Jan 19, 2023 3:36 pm

Great & marvelous!