Starship Asterisk*

Posted: **Wed Sep 28, 2022 4:05 am**

A Furious Sky over Mount Shasta

Explanation: Is the sky angry with Mount Shasta? According to some ancient legends, the spirits of above and below worlds fight there, sometimes quite actively during eruptions of this enormous volcano in California, USA. Such drama can well be imagined in this deep sky image taken in late June. Evident above the snow-covered peak is the central band of our Milky Way Galaxy, on the left, and a picturesque sky toward the modern constellations of Scorpius and Ophiuchus, above and to the right. The bright orange star Antares and the colorful rho Ophiuchi cloud complex are visible just to the right of Mount Shasta, while the red emission nebula surrounding the star zeta Ophiuchi appears on the top right. The static earth image in the featured composite was taken during the blue hour, while a two-panel panorama tracking the background sky was taken later that night with the same camera and from the same location. Within a few million years, Antares, some stars in the rho Ophiuchi system, and zeta Ophiuchi will all likely explode as supernovas.

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Posted: **Wed Sep 28, 2022 5:46 am**

Wow, that's a stunning image!

However, me being me, I do have one nitpick. To show you, I have added some extra annotation to the already richly annotated APOD, to bring out the Pipe Nebula. And near the Pipe Nebula is one of my favorite stars, Theta Ophiuchi, whose lovely azure light is not given full justice in the APOD. Wait, I'll show you!

A furious sky over Mount Shasta. Image: Ralf Rohner.

: The Pipe Nebula and blue star Theta Ophiuchi. Credit and copyright: Jose Mtanos.

Can you see the Pipe Nebula at left in the APOD, which I have marked in light brown? And can you see θ Oph, Theta Ophiuchi, very close to it? It hardly looks blue at all in the APOD.

But Theta Ophiuchi really is a lovely blue star, as you can see in Jose Mtanos' image. Few stars in the sky have a bluer B-V index. The B-V index measures the proportion of blue light to the proportion of yellow-green light emitted by a star (or a galaxy), and the lower the B-V index is, the bluer is the star (or the galaxy).

The fact that Theta Ophiuchi has an unusually blue B-V index is certainly not to say that Theta Ophiuchi is the intrinsically bluest and hottest star in the heavens, even though it is hot. Simbad Astronomical database calls it an OB star of the Beta Cephei type, which probably means it is of early spectral class B. But it is less affected by dust reddening than most O and early B stars in the sky and thus looks bluer than most stars to our eyes.

The only star in Ralf Rohner's superb image that has a bluer B-V index than Theta Ophiuchi is Shaula, Lambda Scorpii, which can be seen in the lower left corner in Rohner's image. Interestingly, Shaula is a Beta Cephei star, too.

So what about the original Beta Cephei star, Beta Cephei itself? Sure, it is a hot and blue star and it stands out - not strikingly so, but it does - in its own constellation.

And of course, the Cepheus constellation also contains one of the redder stars in the sky that is visible to the naked eye, Mu Cephei, also known as the Garnet Star. It is an extremely swollen, cool and luminous star. Antares, you are so out-reddened and out-sized by Mu Cephei!

But I can feel that I'm veering off the topic of today's APOD, so I'm leaving here!

Ann

Posted: **Wed Sep 28, 2022 9:32 am**

Yes, a stunning picture, but more highly processed than McDonald's cheese!
As the blurb describes, the sky and mountain had to be imaged separately and combined to justify the spurious title, as it shows something a human eye could never see. Observations that our eyes cannot see are commonplace, but we invoke physics, not "the spirits of above and below worlds" to explain them.

It's art, but is it legitimate art if it's dressed up as astronomical?
John

Posted: **Wed Sep 28, 2022 9:32 am**

Ann since you love blue stars, I'd like to say I love blue planetary nebulae!

Posted: **Wed Sep 28, 2022 10:16 am**

Ann wrote: ↑Wed Sep 28, 2022 5:46 am Wow, that's a stunning image!

However, me being me, I do have one nitpick. To show you, I have added some extra annotation to the already richly annotated APOD, to bring out the Pipe Nebula. And near the Pipe Nebula is one of my favorite stars, Theta Ophiuchi, whose lovely azure light is not given full justice in the APOD. Wait, I'll show you!

APOD 28 September 2022 extra annotated.png
A furious sky over Mount Shasta. Image: Ralf Rohner.
The Pipe Nebula and blue star Theta Ophiuchi. Credit and copyright: Jose Mtanos.

Can you see the Pipe Nebula at left in the APOD, which I have marked in light brown? And can you see θ Oph, Theta Ophiuchi, very close to it? It hardly looks blue at all in the APOD.

But Theta Ophiuchi really is a lovely blue star, as you can see in Jose Mtanos' image. Few stars in the sky have a bluer B-V index. The B-V index measures the proportion of blue light to the proportion of yellow-green light emitted by a star (or a galaxy), and the lower the B-V index is, the bluer is the star (or the galaxy).

The fact that Theta Ophiuchi has an unusually blue B-V index is certainly not to say that Theta Ophiuchi is the intrinsically bluest and hottest star in the heavens, even though it is hot. Simbad Astronomical database calls it an OB star of the Beta Cephei type, which probably means it is of early spectral class B. But it is less affected by dust reddening than most O and early B stars in the sky and thus looks bluer than most stars to our eyes.

The only star in Ralf Rohner's superb image that has a bluer B-V index than Theta Ophiuchi is Shaula, Lambda Scorpii, which can be seen in the lower left corner in Rohner's image. Interestingly, Shaula is a Beta Cephei star, too.

So what about the original Beta Cephei star, Beta Cephei itself? Sure, it is a hot and blue star and it stands out - not strikingly so, but it does - in its own constellation.

Beta Cep and constellation Cepheus Will Gater.png

And of course, the Cepheus constellation also contains one of the redder stars in the sky that is visible to the naked eye, Mu Cephei, also known as the Garnet Star. It is an extremely swollen, cool and luminous star. Antares, you are so out-reddened and out-sized by Mu Cephei!

But I can feel that I'm veering off the topic of today's APOD, so I'm leaving here!

Ann

The dust on the left in the first picture is it part of one of the spiral arms and which one?

Posted: **Wed Sep 28, 2022 12:28 pm**

Beautiful view of Mt. Shasta, and the annotations are
super! Great job by the photographer!

Posted: **Wed Sep 28, 2022 1:04 pm**

The legend of Llao and Skell makes such perfect geologic sense, I have wondered if it wasn't inspired by the formation of Crater Lake.

Posted: **Wed Sep 28, 2022 2:08 pm**

One thing I don’t care for with composites like these is the way they process it without any atmospheric haze. It’s razor sharp down to the horizon which would only be true in a vacuum, it’s a contributing factor as why so many of these things look so “fakey” IMO.
I don’t have a problem per se with enhanced color except when they go nuts with the saturation. I feel this one is a bit oversaturated but that is another matter of opinion as these images are more art than science which is fine. The scale also seems a bit off but again this is art and is subjective in it’s importance.
I don’t mean to come off as hypercritical but, IMO again, the whole image just doesn’t do it for me though technically the image is impressive.

Eric

Posted: **Wed Sep 28, 2022 3:20 pm**

beryllium732 wrote: ↑Wed Sep 28, 2022 10:16 am
Ann wrote: ↑Wed Sep 28, 2022 5:46 am Wow, that's a stunning image!

However, me being me, I do have one nitpick. To show you, I have added some extra annotation to the already richly annotated APOD, to bring out the Pipe Nebula. And near the Pipe Nebula is one of my favorite stars, Theta Ophiuchi, whose lovely azure light is not given full justice in the APOD. Wait, I'll show you!

Click to view full size image
A furious sky over Mount Shasta. Image: Ralf Rohner.
The Pipe Nebula and blue star Theta Ophiuchi. Credit and copyright: Jose Mtanos.

Can you see the Pipe Nebula at left in the APOD, which I have marked in light brown? And can you see θ Oph, Theta Ophiuchi, very close to it? It hardly looks blue at all in the APOD.

But Theta Ophiuchi really is a lovely blue star, as you can see in Jose Mtanos' image. Few stars in the sky have a bluer B-V index. The B-V index measures the proportion of blue light to the proportion of yellow-green light emitted by a star (or a galaxy), and the lower the B-V index is, the bluer is the star (or the galaxy).

The fact that Theta Ophiuchi has an unusually blue B-V index is certainly not to say that Theta Ophiuchi is the intrinsically bluest and hottest star in the heavens, even though it is hot. Simbad Astronomical database calls it an OB star of the Beta Cephei type, which probably means it is of early spectral class B. But it is less affected by dust reddening than most O and early B stars in the sky and thus looks bluer than most stars to our eyes.

The only star in Ralf Rohner's superb image that has a bluer B-V index than Theta Ophiuchi is Shaula, Lambda Scorpii, which can be seen in the lower left corner in Rohner's image. Interestingly, Shaula is a Beta Cephei star, too.

So what about the original Beta Cephei star, Beta Cephei itself? Sure, it is a hot and blue star and it stands out - not strikingly so, but it does - in its own constellation.

Beta Cep and constellation Cepheus Will Gater.png

And of course, the Cepheus constellation also contains one of the redder stars in the sky that is visible to the naked eye, Mu Cephei, also known as the Garnet Star. It is an extremely swollen, cool and luminous star. Antares, you are so out-reddened and out-sized by Mu Cephei!

But I can feel that I'm veering off the topic of today's APOD, so I'm leaving here!

Ann
The dust on the left in the first picture is it part of one of the spiral arms and which one?

I think you are asking if the Pipe Nebula is part of one of our galaxy's major spiral arms. I'd say no.

Take a look at the Pipe Nebula at left in this cropped and extra annotated version of the APOD. Note that the Pipe Nebula seems to be connected to long streamers of gas and dust that reach all the way into the colorful Antares and Rho Ophiuchi region. The stars of the Antares/Rho Ophiuchi region are located at a distance of some ~500 light-years, and I'd say that the dark dusty streamers, as well as the Pipe Nebula, are at a similar distance.

But take a look at the long dark dust lane to the left of the Pipe Nebula that is interspersed with red emission nebulas and peppered with small white stars. I think - think, mind you - that the dust lane here is part of the Sagittarius Arm, which is one of our galaxy's major spiral arms. The distance to the Sagittarius Arm is some ~4000 light-years.

Ann

Posted: **Wed Sep 28, 2022 9:39 pm**

Alright, with a lot of pain, I managed to find a link to the annotated image from my browser (by viewing the html source for the page):

https://apod.nasa.gov/apod/image/2209/S ... otated.jpg

In contrast, the original unannotated image is:

https://apod.nasa.gov/apod/image/2209/S ... r_1640.jpg

So it's not a matter of simply appending "_annotated" before the .jpg.

Everyone else seems to have had a much easier time finding it. I swear I figured out the trick long ago, but must have forgotten.

Posted: **Wed Sep 28, 2022 10:26 pm**

johnnydeep wrote: ↑Wed Sep 28, 2022 9:39 pm Alright, with a lot of pain, I managed to find a link to the annotated image from my browser (by viewing the html source for the page):

https://apod.nasa.gov/apod/image/2209/S ... otated.jpg

In contrast, the original unannotated image is:

https://apod.nasa.gov/apod/image/2209/S ... r_1640.jpg

So it's not a matter of simply appending "_annotated" before the .jpg.

Everyone else seems to have had a much easier time finding it. I swear I figured out the trick long ago, but must have forgotten.

Actually, the image you first see at https://apod.nasa.gov/apod/ap220928.html is:

https://apod.nasa.gov/apod/image/2209/S ... er_960.jpg

So it is just a matter of simply appending "_annotated" before the .jpg.

Posted: **Thu Sep 29, 2022 12:52 pm**

bystander wrote: ↑Wed Sep 28, 2022 10:26 pm
johnnydeep wrote: ↑Wed Sep 28, 2022 9:39 pm Alright, with a lot of pain, I managed to find a link to the annotated image from my browser (by viewing the html source for the page):

https://apod.nasa.gov/apod/image/2209/S ... otated.jpg

In contrast, the original unannotated image is:

https://apod.nasa.gov/apod/image/2209/S ... r_1640.jpg

So it's not a matter of simply appending "_annotated" before the .jpg.

Everyone else seems to have had a much easier time finding it. I swear I figured out the trick long ago, but must have forgotten.

Actually, the image you first see at https://apod.nasa.gov/apod/ap220928.html is:

https://apod.nasa.gov/apod/image/2209/S ... er_960.jpg

So it is just a matter of simply appending "_annotated" before the .jpg.

Thanks. Yeah, I was fooled by the fact that the "hover over" link displayed by my browser was https://apod.nasa.gov/apod/image/2209/S ... r_1640.jpg

But what's actually being shown when the page is first displayed is controlled by this HTML code:

<a href="image/2209/ShastaSky_Rohner_1640.jpg"
onMouseOver="if (document.images)
document.imagename1.src='image/2209/ShastaSky_Rohner_960_annotated.jpg';"
onMouseOut="if (document.images)
document.imagename1.src='image/2209/ShastaSky_Rohner_960.jpg';">

Posted: **Sun Oct 02, 2022 10:14 pm**

Ann wrote: ↑Wed Sep 28, 2022 3:20 pm
beryllium732 wrote: ↑Wed Sep 28, 2022 10:16 am
Ann wrote: ↑Wed Sep 28, 2022 5:46 am Wow, that's a stunning image!

However, me being me, I do have one nitpick. To show you, I have added some extra annotation to the already richly annotated APOD, to bring out the Pipe Nebula. And near the Pipe Nebula is one of my favorite stars, Theta Ophiuchi, whose lovely azure light is not given full justice in the APOD. Wait, I'll show you!

Click to view full size image
A furious sky over Mount Shasta. Image: Ralf Rohner.
The Pipe Nebula and blue star Theta Ophiuchi. Credit and copyright: Jose Mtanos.

Can you see the Pipe Nebula at left in the APOD, which I have marked in light brown? And can you see θ Oph, Theta Ophiuchi, very close to it? It hardly looks blue at all in the APOD.

But Theta Ophiuchi really is a lovely blue star, as you can see in Jose Mtanos' image. Few stars in the sky have a bluer B-V index. The B-V index measures the proportion of blue light to the proportion of yellow-green light emitted by a star (or a galaxy), and the lower the B-V index is, the bluer is the star (or the galaxy).

The fact that Theta Ophiuchi has an unusually blue B-V index is certainly not to say that Theta Ophiuchi is the intrinsically bluest and hottest star in the heavens, even though it is hot. Simbad Astronomical database calls it an OB star of the Beta Cephei type, which probably means it is of early spectral class B. But it is less affected by dust reddening than most O and early B stars in the sky and thus looks bluer than most stars to our eyes.

The only star in Ralf Rohner's superb image that has a bluer B-V index than Theta Ophiuchi is Shaula, Lambda Scorpii, which can be seen in the lower left corner in Rohner's image. Interestingly, Shaula is a Beta Cephei star, too.

So what about the original Beta Cephei star, Beta Cephei itself? Sure, it is a hot and blue star and it stands out - not strikingly so, but it does - in its own constellation.

Beta Cep and constellation Cepheus Will Gater.png

And of course, the Cepheus constellation also contains one of the redder stars in the sky that is visible to the naked eye, Mu Cephei, also known as the Garnet Star. It is an extremely swollen, cool and luminous star. Antares, you are so out-reddened and out-sized by Mu Cephei!

But I can feel that I'm veering off the topic of today's APOD, so I'm leaving here!

Ann
The dust on the left in the first picture is it part of one of the spiral arms and which one?

I think you are asking if the Pipe Nebula is part of one of our galaxy's major spiral arms. I'd say no.

APOD 28 September 2022 extra annotated cropped.png

Take a look at the Pipe Nebula at left in this cropped and extra annotated version of the APOD. Note that the Pipe Nebula seems to be connected to long streamers of gas and dust that reach all the way into the colorful Antares and Rho Ophiuchi region. The stars of the Antares/Rho Ophiuchi region are located at a distance of some ~500 light-years, and I'd say that the dark dusty streamers, as well as the Pipe Nebula, are at a similar distance.

But take a look at the long dark dust lane to the left of the Pipe Nebula that is interspersed with red emission nebulas and peppered with small white stars. I think - think, mind you - that the dust lane here is part of the Sagittarius Arm, which is one of our galaxy's major spiral arms. The distance to the Sagittarius Arm is some ~4000 light-years.

Ann

I meant the dust left of the Pipe Nebula but thank you that's really cool! Really like your posts!

Starship Asterisk*

APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

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Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)