Starship Asterisk*

[quote=Locutus76 post_id=337276 time=1708512704 user_id=144427]
This gorgeous nebula always make me think of Godzilla’s Rodan, rather than a seagull.
[img] https://upload.wikimedia.org/wikipedia/commons/8/86/Rodan_poster_detail.jpg[/img]
[/quote]

Agreed - or a Diatryma's first ever flight...

[quote=Ann post_id=337287 time=1708526128 user_id=129702]
[quote=johnnydeep post_id=337282 time=1708523816 user_id=132061]
Also, what's that very bright area at the tip of the left wing (at the lower right in the image)?
[/quote]

That's reflection nebula vdB 94. It surrounds B1II/III star HD HD 53623, which is hot enough to ionize a red emission nebula, but also "cool" enough (probably at least 20,000 K) not to blow all the surrounding dust away all too quickly. The star's blue light is reflected in the dusty reflection nebula, but its ultraviolet light ionizes a (pretty small) red emission nebula, Sharpless 297.


[img3="Reflection nebula vdB 94. Credit: Velimir Popov and Emil Ivanov."]https://www.irida-observatory.org/CCD/VdB94/VdB94_1100.jpg[/img3]


Ann
[/quote]

✔️

[quote=johnnydeep post_id=337282 time=1708523816 user_id=132061]
Also, what's that very bright area at the tip of the left wing (at the lower right in the image)?
[/quote]

That's reflection nebula vdB 94. It surrounds B1II/III star HD HD 53623, which is hot enough to ionize a red emission nebula, but also "cool" enough (probably at least 20,000 K) not to blow all the surrounding dust away all too quickly. The star's blue light is reflected in the dusty reflection nebula, but its ultraviolet light ionizes a (pretty small) red emission nebula, Sharpless 297.


[img3="Reflection nebula vdB 94. Credit: Velimir Popov and Emil Ivanov."]https://www.irida-observatory.org/CCD/VdB94/VdB94_1100.jpg[/img3]


Ann

Also, what's that very bright area at the tip of the left wing (at the lower right in the image)?

Here's an image with some other "objects" annotated:


[img2]https://www.nebulaphotos.com/img/ic2177-annotatedMedium.jpg[/img2]

Yes, the Seagull Nebula is "small" when compared to Barnard's Loop, but it's large compared to the Full Moon! Per the text, it's 5 times as wide:


[attachment=0]seagull nebula size compared to moon.jpg[/attachment]

[quote=Rauf post_id=337278 time=1708516485 user_id=144493]
[quote=Astronut post_id=337277 time=1708515379 user_id=146872]
What is the distance of the Seagull Nebula from earth?
[/quote]

https://apod.nasa.gov/apod/ap090327.html

Well, an old APOD mentioned this.

[quote]Dominated by the reddish glow of atomic hydrogen, the complex of cosmic gas and dust clouds with bright young stars spans over 250 light-years at an estimated 3,800 light-year distance.

[/quote]
[/quote]

I checked the Gaia parallaxes of a few of the blue stars in the Seagull Nebula. FN CMa does not, unfortunately, have a Gaia parallax (probably because the nebulosity next to it makes it hard for Gaia to get reliable measurements of its parallax), but another blue star in the Seagull Nebula, HD 53755, has a Gaia parallax of 0.9091±0.0441 milliarcseconds. Disregarding the uncertainly, this parallax gives a distance to HD 53755 of ~3,600 light-years.

Ann

[quote=Astronut post_id=337277 time=1708515379 user_id=146872]
What is the distance of the Seagull Nebula from earth?
[/quote]

https://apod.nasa.gov/apod/ap090327.html

Well, an old APOD mentioned this.

[quote]Dominated by the reddish glow of atomic hydrogen, the complex of cosmic gas and dust clouds with bright young stars spans over 250 light-years at an estimated 3,800 light-year distance.

[/quote]

What is the distance of the Seagull Nebula from earth?

This gorgeous nebula always make me think of Godzilla’s Rodan, rather than a seagull.
[img] https://upload.wikimedia.org/wikipedia/commons/8/86/Rodan_poster_detail.jpg[/img]

[img3="Seagull Nebula over Pinnacles' Peak.
Image Credit & Copyright: Dheera Venkatraman"]https://apod.nasa.gov/apod/image/2402/SeagullPinnacles_Venkatraman_960.jpg[/img3]


What i like best about this APOD is that the Seagull Nebula is really red. Because it [b][i]is[/i][/b] really red. Yeah, [url=https://www.focalworld.com/threads/seagull-nebula.21970/]with the help of narrowband photography[/url] you can bring out other colors in it, but honestly, it's just so red.

What I don't like much about the APOD is that it doesn't bring out any blue light at all in any of the stars or in any parts of the nebula. That's bad, because there really are stars and small nebulas in the larger Seagull Nebula that really are bluish.


[float=left][attachment=1]APOD 21 February 2024 detail annotated.png[/attachment][/float][float=right][img3="Blue bow shock of CMa. Credit: Patrick A. Cosgrove"]https://images.squarespace-cdn.com/content/v1/60d7296aaa6c862de19a7d3b/86112a81-6eaa-4a2c-b27a-516185f45484/IC2177WM-WEB.jpg?format=2500w[/img3][/float]
[clear][/clear]


Patrick Cosgrove's picture is a narrowband one, and the blue color probably means OIII. You can't be sure that an object that looks blue in a narrowband image would look blue in an RGB image, but this RGB+HαOIII picture by Matt Harbison shows FN CMa as blue, too:


[img3="Very blue-looking FN CMa in the Seagull Nebula. Credit: Matt Harbison."]https://space4everybody.com/wp-content/uploads/2021/03/Seagull-Master-Cuts-4-1-1024x528.jpg[/img3]


So much for the color of today's APOD. An interesting aspect of the picture is that it makes the Seagull Nebula look absolutely huge in the sky. So how big is it really? The best I can do for you is how you this image of hydrogen alpha nebulas in the sky in black and white:


[float=left][img3="Winter and summer Milky Way in H-alpha. Credit: mandarpotdar of Cloudy Nights."]https://www.cloudynights.com/uploads/monthly_03_2019/post-35178-0-62855900-1552383628.jpg[/img3][/float][float=right][attachment=0]Orion and Seagull in Hα black and white mandarpotdar.png[/attachment][c][size=85][color=#0040FF]Orion and Seagull in Hα.[/color][/size][/c][/float]
[clear][/clear]


So as you can see, the Seagull Nebula is smaller than Barnard's Loop in Orion (the big C-shaped thing in Orion). It's smaller than the Lambda Orionis Nebula (the big round thing to the upper right of Barnard's Loop). But it is a lot bigger than the Orion Nebula (the brilliantly bright small object inside Barnard's Loop).

But if you want to see the Seagull Nebula and its surroundings in its full glory, take a look at this gorgeous image by Matt Harbison:


[img3="The Seagull in its true element. Credit: Matt Harbison"]https://space4everybody.com/wp-content/uploads/2021/03/Seagull-Master-8K-NR-1-1-2048x1057.jpg[/img3]

Ann

[url=https://apod.nasa.gov/apod/ap240221.html] [img]https://apod.nasa.gov/apod/calendar/S_240221.jpg[/img] [size=150]Seagull Nebula over Pinnacles' Peak[/size][/url]

[b] Explanation: [/b] The bird is bigger than the peak. Nicknamed for its [url=https://en.wiktionary.org/wiki/avian#Adjective]avian[/url] shape, the [url=https://apod.nasa.gov/apod/ap230119.html]Seagull Nebula[/url] is an [url=https://apod.nasa.gov/apod/emission_nebulae.html]emission nebula[/url] on the night sky that is [url=https://apod.nasa.gov/apod/ap240123.html]vast[/url], spanning an angle over five times the diameter of the [url=https://apod.nasa.gov/apod/ap220612.html]full moon[/url] and over 200 [url=https://spaceplace.nasa.gov/light-year/]light years[/url]. The head of the nebula is catalogued as [url=https://en.wikipedia.org/wiki/IC_2177]IC 2177[/url], and the star cluster under its right wing is catalogued as NGC 2343. Consisting of mostly red-glowing [url=https://periodic.lanl.gov/1.shtml]hydrogen[/url] gas, the [url=https://apod.nasa.gov/apod/ap180316.html]Seagull Nebula[/url] incorporates some dust lanes and is forming [url=https://science.nasa.gov/universe/stars/]stars[/url]. The peak over which this Seagull [url=https://i1.sndcdn.com/avatars-000031354923-a6ixw8-t500x500.jpg]seems to soar[/url] occurs at [url=https://en.wikipedia.org/wiki/Pinnacles_National_Park]Pinnacles National Park[/url] in [url=https://en.wikipedia.org/wiki/California]California[/url], [url=https://en.wikipedia.org/wiki/United_States]USA[/url]. The [url=https://www.instagram.com/p/CKXdL1YndQi/]featured image[/url] is a composite of long exposure images of the background sky and short exposure images of the foreground, all taken consecutively with the same camera and from the same location.


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