Starship Asterisk*

M27: Not a Comet

Explanation: While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things encountered during his telescopic expeditions that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color image highlights details within the well-studied central region and fainter, seldom imaged features in the nebula's outer halo.

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I'm not copying the APOD and posting it here, because it is too large! :stamps-foot: It's almost 700 KB.

So I recommend this thread instead, where you can see a dizzying variety of Dumbbell Nebulas in all the colors of the rainbow! I'm posting two of my favorites here:


So what color is M27 really? Well, planetary nebulas are typically dominated by either cyan-green OIII, whose color is probably something like this, ███, or red hydrogen alpha, which is, well, red, ███. Or, most likely, most planetaries are both OIII-green and Hα-red, like M27.

What makes a star shed its outer layers anyway? It has to do with the pulsations and dust production of the dying red asymptotic giant branch (AGB) star. An AGB star formed from a sunlike progenitor will have an inert core and two shells where fusion is taking place:


So the AGB star has two shells where fusion is taking place, a hydrogen-burning shell and a helium-burning shell. The way I understand it, the hydrogen-burning shell affects the helium-burning shell by dumping more helium on the helium-burning shell. This makes the helium-burning shell fuse in an uneven manner, causing it to pulsate. Also the way I understand it, these pulsations help create dust:

F Dell'Agli et al. wrote:

Asymptotic giant branch (AGB) stars are efficient pollutants of the interstellar medium, because their cool and dense winds prove a favourable environment for dust production. For example, these stars are known to significantly contribute to the chemical enrichment of galaxies as well as up to 40 per cent of interstellar medium dust (e.g. Schneider et al. 2014; Goldman et al. 2022).

The reason why post-AGB stars shed their outer layers is, the way I understand it, the fact that the pulsations create winds that themselves blow away the outer layers of the star's atmosphere, and the extra dust created by the pulsations makes in even easier for the winds to get a good hold on the atmosphere and blow away its dust, taking gas with it.

Of course, once the ultra-hot but cooling inert core has been bared, and its ultra-harsh ultraviolet light is bathing the still nearby gaseous shells and curtains of removed outer stellar atmosphere, then these curtains and shells begin to fluoresce, and we get a planetary nebula.



All right. I don't have much more to say about the AGB stars or the white dwarfs. But I'll say this much. No, M27 is not a comet, but there are many things that are not comets! For example, AGB star Mira, which is shedding its outer layers while at the same time speeding through space, is leaving a 13 light-year-long ultraviolet tail behind it. But it is not a comet.



Also the False Comet in Scorpius is not a comet:


And the Comet Galaxy is also not a comet!

Wikipedia wrote about the Comet Galaxy:

This unique spiral galaxy, which is situated 3.2 billion light-years from the Earth, has an extended stream of bright blue knots and diffuse wisps of young stars. It rushes at 3.6 million km/h (1000km/s) through the cluster Abell 2667 and therefore, like a comet, shows a tail, with a length of 600,000 light-years.

Not even comet-like galaxy NGC 4861 is a comet:


So, to summarize, there are more things that are not comets in Heaven and Earth, Horatio, than are dreamt of in your philosophy. Like 110 Messier objects. And many other things as well.

Ann

A non astronomical question: what's the ornate design at http://www.messier.seds.org/xtra/history/m-cat.html ? It looks like the letters "M" and "R" and maybe others. I'd guess it's related to Charles Messier's initials or ... what?


And since when can't a tiny .jpg file not be displayed? Is it TOO tiny: 200 × 197, 9.99 kB ?

<sigh> The image is here: http://www.messier.seds.org/Pics/History/m-colo.jpg

The extreme zoom-in by Hubble to a small portion of M27 at the "Dumbbell Nebula" link is quite impressive. No idea where this is located withing this APOD's larger view:

Haha, wonderful examples of not-comets. I would say the top unappreciated not-a-comet is when you have a smudge on your lens.

Just a little more pedantic color discussion. I have seen hydrogen emission with my own eyes from the sun during a total eclipse, and it appears neon pink, not deep red. Hydrogen emission is pink because the hydrogen alpha line and the beta line and others mix together, and that is also happening for planetary nebulas, right? It's only deep red if you have just one atom doing one transition. With a cloud of ionized hydrogen, it's basically 50/50 mix of electrons making the alpha or the beta transition, and the others are less likely, so it would look pink, at least to some sort of super human with giant eyeballs.

But with the aid of a telescope, we can see the "true color" to the human eye is no color at all because it's still too dim. At a star party, when I'm showing people M27 or the like through a telescope, usually someone is a little disappointed with the lack of color, I'll get questions like "what if we were closer, then would it look like those Hubble images I've seen?"

And I never know quite what to say to make them feel better. Sometimes I'll just say, no, this is about as good as it gets, the light is so faint and diffuse that if we were inside it, it still wouldn't look brighter. Sometimes I talk about the limitations of the human eye, that if we could collect more light like a camera, then it would look a little better. I've heard that all types of deer, although they are red-green colorblind, with their large eyes, good light sensitivity, probably see the Milky Way as bright and colorful as it appears in an Instagram saturated photo. And hawks have such sharp vision they can see the moons of Jupiter, but they probably don't know what they are.

johnnydeep wrote: ↑Sat Oct 05, 2024 1:05 pm The extreme zoom-in by Hubble to a small portion of M27 at the "Dumbbell Nebula" link is quite impressive. No idea where this is located withing this APOD's larger view:

Click to view full size image

Check out the Youtube video that you can find in your own link, and then you'll see what part of the Dumbbell Nebula was scrutinized by Hubble.


Ann

florid_snow wrote: ↑Sat Oct 05, 2024 2:50 pm Haha, wonderful examples of not-comets. I would say the top unappreciated not-a-comet is when you have a smudge on your lens.

Just a little more pedantic color discussion. I have seen hydrogen emission with my own eyes from the sun during a total eclipse, and it appears neon pink, not deep red. Hydrogen emission is pink because the hydrogen alpha line and the beta line and others mix together, and that is also happening for planetary nebulas, right? It's only deep red if you have just one atom doing one transition. With a cloud of ionized hydrogen, it's basically 50/50 mix of electrons making the alpha or the beta transition, and the others are less likely, so it would look pink, at least to some sort of super human with giant eyeballs.

Hydrogen emission is indeed a mixture of hydrogen alpha, ███, and hydrogen beta, ███. There is always more hydrogen alpha than hydrogen beta, but you are right, hydrogen beta is always present. In narrowband photography, the hydrogen filter used is almost always 656 nm only. Almost always, no filter is used to detect hydrogen beta at 486 nm. Therefore, the "true" pink hue of hydrogen emission is not seen in narrowband photography.

But with the aid of a telescope, we can see the "true color" to the human eye is no color at all because it's still too dim. At a star party, when I'm showing people M27 or the like through a telescope, usually someone is a little disappointed with the lack of color, I'll get questions like "what if we were closer, then would it look like those Hubble images I've seen?"

And I never know quite what to say to make them feel better. Sometimes I'll just say, no, this is about as good as it gets, the light is so faint and diffuse that if we were inside it, it still wouldn't look brighter. Sometimes I talk about the limitations of the human eye, that if we could collect more light like a camera, then it would look a little better. I've heard that all types of deer, although they are red-green colorblind, with their large eyes, good light sensitivity, probably see the Milky Way as bright and colorful as it appears in an Instagram saturated photo. And hawks have such sharp vision they can see the moons of Jupiter, but they probably don't know what they are.

Don't be too sure about that!


Ann

Ann wrote: ↑Sat Oct 05, 2024 2:51 pm

johnnydeep wrote: ↑Sat Oct 05, 2024 1:05 pm The extreme zoom-in by Hubble to a small portion of M27 at the "Dumbbell Nebula" link is quite impressive. No idea where this is located withing this APOD's larger view:

Click to view full size image

Check out the Youtube video that you can find in your own link, and then you'll see what part of the Dumbbell Nebula was scrutinized by Hubble.

....
Ann

Indeed. Thanks:

johnnydeep wrote: ↑Sat Oct 05, 2024 4:28 pm

Ann wrote: ↑Sat Oct 05, 2024 2:51 pm

johnnydeep wrote: ↑Sat Oct 05, 2024 1:05 pm The extreme zoom-in by Hubble to a small portion of M27 at the "Dumbbell Nebula" link is quite impressive. No idea where this is located withing this APOD's larger view:

Click to view full size image

Check out the Youtube video that you can find in your own link, and then you'll see what part of the Dumbbell Nebula was scrutinized by Hubble.

....
Ann

Indeed. Thanks:


dbumbbell nebula zoom-in.jpg

Well observed.

I don't want to sound pedantic, but for the area of ​​the actual nebula of this APOD Hubble data was used,
which can be seen from the bright spots in the center of the stars.

This means that it is unclear what comes from the named authors and what from external sources.
This fact would have to be declared.

florid_snow wrote: ↑Sat Oct 05, 2024 2:50 pm Haha, wonderful examples of not-comets. I would say the top unappreciated not-a-comet is when you have a smudge on your lens.

Just a little more pedantic color discussion. I have seen hydrogen emission with my own eyes from the sun during a total eclipse, and it appears neon pink, not deep red. Hydrogen emission is pink because the hydrogen alpha line and the beta line and others mix together, and that is also happening for planetary nebulas, right? It's only deep red if you have just one atom doing one transition. With a cloud of ionized hydrogen, it's basically 50/50 mix of electrons making the alpha or the beta transition, and the others are less likely, so it would look pink, at least to some sort of super human with giant eyeballs.

But with the aid of a telescope, we can see the "true color" to the human eye is no color at all because it's still too dim. At a star party, when I'm showing people M27 or the like through a telescope, usually someone is a little disappointed with the lack of color, I'll get questions like "what if we were closer, then would it look like those Hubble images I've seen?"

And I never know quite what to say to make them feel better. Sometimes I'll just say, no, this is about as good as it gets, the light is so faint and diffuse that if we were inside it, it still wouldn't look brighter. Sometimes I talk about the limitations of the human eye, that if we could collect more light like a camera, then it would look a little better. I've heard that all types of deer, although they are red-green colorblind, with their large eyes, good light sensitivity, probably see the Milky Way as bright and colorful as it appears in an Instagram saturated photo. And hawks have such sharp vision they can see the moons of Jupiter, but they probably don't know what they are.

My experience with eclipses is that really bright prominences look deep ruby red, and it is only the less bright ones that look more like pink. I'm doubtful that this is because of H-beta emission, but rather, I think it's simple desaturation caused by the mix of H-alpha and continuum white light from the corona. Neither my eyes nor my camera captures anything I'd describe as magenta, which would be what we'd get from a significant H-beta contribution.

The limitation with our eyes is primarily one of not being able to integrate photons. Our eyes are cameras that can't take exposures longer than a few tens of milliseconds, and there just aren't many photons coming from astronomical objects in that interval (and a telescope doesn't help deliver more... so like you said, you're never going to get a better view than through a telescope, and that's going to be low contrast and largely colorless. The same thing you'd see if you were 100 times closer to the object).

Hahaha, Ann, that's great, thank you, I'm saving that hawk image. Hawks probably love Europa, who's to say?

But may I please continue discussion about the proportion of H-beta. I certainly willing to be wrong about anything, including the reason for the solar prominences appearing pink, I agree Chris it could just be continuum white light from the corona, also there's got to be some significant spectral broadening from all sorts of things going on near the sun that would be different from a planetary nebula. But my eyes and camera did capture something I would describe as either pink or magenta, maybe I have crude color sensitivity, this is certainly subjective.

But why would the H-beta emission not occur? I'm willing to accept it's less than a 50/50 mix, but the H-beta emission has got to be there too. These "magenta" or pink colors look the same to me. I used the color-picker tool in microsoft paint to consider and compare the colors. It does seem like certain regions are magenta, and others are deep red. Maybe that's more diffuse hydrogen vs. more coronal broad-spectrum? But why not just more regions where the other lines occur, why would they not occur? Here is a quote from the wikipedia page, but it does cite a textbook:
"After ionization, the electron and proton recombine to form a new hydrogen atom. In the new atom, the electron may begin in any energy level, and subsequently cascades to the ground state (n = 1), emitting photons with each transition. Approximately half the time, this cascade will include the n = 3 to n = 2 transition and the atom will emit H-alpha light."
From https://en.wikipedia.org/wiki/Hydrogen-alpha, with a citation to A. N. Cox, ed. (2000). Allen's Astrophysical Quantities. New York: Springer-Verlag. ISBN 0-387-98746-0.

Why does it say "approximately half the time"?

Let's consider the energy transition calculation. So, excluding the constant, for the H-alpha transition we have (1/4) - (1/9) ~= .139,
and for H-beta we have (1/4) - (1/16) ~= .188, so taking the ratio of these two we get 188/139 ~= 1.35, and I know this is a lot of handwaving, but to me, if the energy associated with the transition of H-beta is only 1.35x larger than that associated with H-alpha, they are both probably occurring plenty enough together in a planetary nebula.

To me, narrow-band photography doesn't mean you have to ignore physics. If we know H-beta emission occurs maybe 25/75 to H-alpha emission, and you take a photo with your H-alpha filter, then why pretend that the H-beta wasn't there too?

florid_snow wrote: ↑Sat Oct 05, 2024 10:16 pm To me, narrow-band photography doesn't mean you have to ignore physics. If we know H-beta emission occurs maybe 25/75 to H-alpha emission, and you take a photo with your H-alpha filter, then why pretend that the H-beta wasn't there too?

Is there some such suggestion being made by anybody? H-beta filters are used for visual astronomy, and narrow H-beta filters are used scientifically. In particular, the ratio of H-alpha to H-beta is used to estimate reddening from interstellar dust. In general, we use H filters because we want to isolate hydrogen in nebulas, and since H-alpha is much stronger than H-beta, we opt for the former.

Thank you very much Chris for more info! You asked "Is there some such suggestion being made by anybody"? And perhaps I misunderstand your tone, but the answer is yes, hello, it's me, I'm not alone, there are literally dozens of us, maybe, making the suggestion for photography presented to the public to include more magenta-pink colors and explanations there-of, even if only the H-alpha was captured by the camera, if we know from physics that it never occurs alone, then why present it alone?

I feel like the exact proportion should be possible to approximate for different conditions, I can't find a plot of power spectral density after literally tens of minutes of searching for it, so I must give up for now, the stars are out tonight.

Also, Johnny Deep, the weird inscription you noticed was just a popular way of doing fancy cursive for your own name used at the time. Search "fancy monograms from history" to learn more. It's basically his initials with fancy cursive jibberish. A notable lover of history who continued this questionably decorative style for monograms was JRR Tolkein, and his kids also sign their names this way to this very day. If you can get one of their signatures in a book of his, it becomes very valuable.

florid_snow wrote: ↑Sun Oct 06, 2024 2:51 am Thank you very much Chris for more info! You asked "Is there some such suggestion being made by anybody"? And perhaps I misunderstand your tone, but the answer is yes, hello, it's me, I'm not alone, there are literally dozens of us, maybe, making the suggestion for photography presented to the public to include more magenta-pink colors and explanations there-of, even if only the H-alpha was captured by the camera, if we know from physics that it never occurs alone, then why present it alone?

I feel like the exact proportion should be possible to approximate for different conditions, I can't find a plot of power spectral density after literally tens of minutes of searching for it, so I must give up for now, the stars are out tonight.

Also, Johnny Deep, the weird inscription you noticed was just a popular way of doing fancy cursive for your own name used at the time. Search "fancy monograms from history" to learn more. It's basically his initials with fancy cursive jibberish. A notable lover of history who continued this questionably decorative style for monograms was JRR Tolkein, and his kids also sign their names this way to this very day. If you can get one of their signatures in a book of his, it becomes very valuable.

I understood you to be suggesting that people are pretending H-beta isn't there.

I personally have no interest in trying to create some kind of accurate color when doing narrowband imaging, but I know some people mix 15-40% of their H-alpha signal into the green channel, or possible into a combination of the green and blue channels, to approximate what could be considered a visual color equivalent of the two emission lines.

And I never know quite what to say to make them feel better. Sometimes I'll just say, no, this is about as good as it gets, the light is so faint and diffuse that if we were inside it, it still wouldn't look brighter. Sometimes I talk about the limitations of the human eye, that if we could collect more light like a camera, then it would look a little better. I've heard that all types of deer, although they are red-green colorblind, with their large eyes, good light sensitivity, probably see the Milky Way as bright and colorful as it appears in an Instagram saturated photo. And hawks have such sharp vision they can see the moons of Jupiter, but they probably don't know what they are.

Nice comments.
You might like this:
https://journals.plos.org/plosbiology/a ... io.3002444

florid_snow wrote: ↑Sun Oct 06, 2024 2:51 am ...
Also, Johnny Deep, the weird inscription you noticed was just a popular way of doing fancy cursive for your own name used at the time. Search "fancy monograms from history" to learn more. It's basically his initials with fancy cursive jibberish. A notable lover of history who continued this questionably decorative style for monograms was JRR Tolkein, and his kids also sign their names this way to this very day. If you can get one of their signatures in a book of his, it becomes very valuable.

Yeah, but, Tolkien's monogram is comprehensible. The name here is Charles Messier, with initials C.M. There's no middle name as far as I can find. So what the heck letters are supposed to be in this decorative monogram? I see "M" at the start, and "R" at the end, and maybe a huge "C" right after the "
M". I can also justify a "J" or two. So what letters are intended to be depicted here? "Messier, Charles, Fellow of the Royal Astronomical Society" or ... something?



In contrast, here are some comprehensible monograms:

Usually, I can click on the names of the person (people) responsible for an APOD and see on their website the details of how an image was captured. In this case, both names lead to the same website that is fraught with so many errors, I can’t even find the image in question much less any capture data. With the extent of the nebulosity, I assume there are a great many hours invested here.

DocO wrote: ↑Mon Oct 07, 2024 11:10 am Usually, I can click on the names of the person (people) responsible for an APOD and see on their website the details of how an image was captured. In this case, both names lead to the same website that is fraught with so many errors, I can’t even find the image in question much less any capture data. With the extent of the nebulosity, I assume there are a great many hours invested here.

[ EDIT: on second look, the Astrobin image it's not the same image at all, though it's still M27 and the same photographers! ]

Yeah, it’s often not easy to suss out the photographic details of the image presented in the APOD. Direct links are often not provided. I googled for “ Francesco Sferlazza, Franco Sgueglia m27” and found what I think is the same image on Astrobin (though the resolution and file size are much higher in this APOD). See https://www.astrobin.com/372278/

Equipment
Imaging Telescopes Or Lenses: Celestron EdgeHD 9.25"
Imaging Cameras: Moravian G2-8300FW
Mounts: sky-watcher eq8
Software: Adobe Photoshop
Guiding Telescopes Or Lenses: Celestron EdgeHD 9.25"

Acquisition details
Dates: Sept. 9, 2018
Frames: 48×900″(12h)
Integration: 12h
Avg. Moon age: 29.26 days
Avg. Moon phase: 0.08%

Basic astrometry details
Astrometry.net job: 2316967
RA center: 19h59m35s.5
DEC center: +22°43′22″
Pixel scale: 0.691 arcsec/pixel
Orientation: 5.336 degrees
Field radius: 0.186 degrees
Resolution: 1499x1228
File size: 832.7 KB
Locations: Parco di Monte Brallo, Colleri, Pavia, None
Data source: Own remote observatory

johnnydeep wrote: ↑Mon Oct 07, 2024 11:55 am

DocO wrote: ↑Mon Oct 07, 2024 11:10 am Usually, I can click on the names of the person (people) responsible for an APOD and see on their website the details of how an image was captured. In this case, both names lead to the same website that is fraught with so many errors, I can’t even find the image in question much less any capture data. With the extent of the nebulosity, I assume there are a great many hours invested here.

[ EDIT: on second look, the Astrobin image it's not the same image at all, though it's still M27 and the same photographers! ]

Yeah, it’s often not easy to suss out the photographic details of the image presented in the APOD. Direct links are often not provided. I googled for “ Francesco Sferlazza, Franco Sgueglia m27” and found what I think is the same image on Astrobin (though the resolution and file size are much higher in this APOD). See https://www.astrobin.com/372278/

Equipment
Imaging Telescopes Or Lenses: Celestron EdgeHD 9.25"
Imaging Cameras: Moravian G2-8300FW
Mounts: sky-watcher eq8
Software: Adobe Photoshop
Guiding Telescopes Or Lenses: Celestron EdgeHD 9.25"

Acquisition details
Dates: Sept. 9, 2018
Frames: 48×900″(12h)
Integration: 12h
Avg. Moon age: 29.26 days
Avg. Moon phase: 0.08%

Basic astrometry details
Astrometry.net job: 2316967
RA center: 19h59m35s.5
DEC center: +22°43′22″
Pixel scale: 0.691 arcsec/pixel
Orientation: 5.336 degrees
Field radius: 0.186 degrees
Resolution: 1499x1228
File size: 832.7 KB
Locations: Parco di Monte Brallo, Colleri, Pavia, None
Data source: Own remote observatory

Well I think that's true, whatever led to a version being mistakenly shown that was pimped up using Hubble data & Co.

https://www.starobserver.org/ap241005/



PS.: I also like the core in infrared ,-)
Original data: NASA/ESA (SST) jac berne (flickr)

AVAO wrote: ↑Mon Oct 07, 2024 8:45 pm

johnnydeep wrote: ↑Mon Oct 07, 2024 11:55 am

DocO wrote: ↑Mon Oct 07, 2024 11:10 am Usually, I can click on the names of the person (people) responsible for an APOD and see on their website the details of how an image was captured. In this case, both names lead to the same website that is fraught with so many errors, I can’t even find the image in question much less any capture data. With the extent of the nebulosity, I assume there are a great many hours invested here.

[ EDIT: on second look, the Astrobin image it's not the same image at all, though it's still M27 and the same photographers! ]

Yeah, it’s often not easy to suss out the photographic details of the image presented in the APOD. Direct links are often not provided. I googled for “ Francesco Sferlazza, Franco Sgueglia m27” and found what I think is the same image on Astrobin (though the resolution and file size are much higher in this APOD). See https://www.astrobin.com/372278/

Equipment
Imaging Telescopes Or Lenses: Celestron EdgeHD 9.25"
Imaging Cameras: Moravian G2-8300FW
Mounts: sky-watcher eq8
Software: Adobe Photoshop
Guiding Telescopes Or Lenses: Celestron EdgeHD 9.25"

Acquisition details
Dates: Sept. 9, 2018
Frames: 48×900″(12h)
Integration: 12h
Avg. Moon age: 29.26 days
Avg. Moon phase: 0.08%

Basic astrometry details
Astrometry.net job: 2316967
RA center: 19h59m35s.5
DEC center: +22°43′22″
Pixel scale: 0.691 arcsec/pixel
Orientation: 5.336 degrees
Field radius: 0.186 degrees
Resolution: 1499x1228
File size: 832.7 KB
Locations: Parco di Monte Brallo, Colleri, Pavia, None
Data source: Own remote observatory

Well I think that's true, whatever led to a version being mistakenly shown that was pimped up using Hubble data & Co.

https://www.starobserver.org/ap241005/



PS.: I also like the core in infrared ,-)

Click to view full size image

Original data: NASA/ESA (SST) jac berne (flickr)

What's true? That the Astrobin image really is the same as the APOD image, just manipulated in some way?

johnnydeep wrote: ↑Mon Oct 07, 2024 8:56 pm

AVAO wrote: ↑Mon Oct 07, 2024 8:45 pm

johnnydeep wrote: ↑Mon Oct 07, 2024 11:55 am

[ EDIT: on second look, the Astrobin image it's not the same image at all, though it's still M27 and the same photographers! ]

Yeah, it’s often not easy to suss out the photographic details of the image presented in the APOD. Direct links are often not provided. I googled for “ Francesco Sferlazza, Franco Sgueglia m27” and found what I think is the same image on Astrobin (though the resolution and file size are much higher in this APOD). See https://www.astrobin.com/372278/

Equipment
Imaging Telescopes Or Lenses: Celestron EdgeHD 9.25"
Imaging Cameras: Moravian G2-8300FW
Mounts: sky-watcher eq8
Software: Adobe Photoshop
Guiding Telescopes Or Lenses: Celestron EdgeHD 9.25"

Acquisition details
Dates: Sept. 9, 2018
Frames: 48×900″(12h)
Integration: 12h
Avg. Moon age: 29.26 days
Avg. Moon phase: 0.08%

Basic astrometry details
Astrometry.net job: 2316967
RA center: 19h59m35s.5
DEC center: +22°43′22″
Pixel scale: 0.691 arcsec/pixel
Orientation: 5.336 degrees
Field radius: 0.186 degrees
Resolution: 1499x1228
File size: 832.7 KB
Locations: Parco di Monte Brallo, Colleri, Pavia, None
Data source: Own remote observatory

Well I think that's true, whatever led to a version being mistakenly shown that was pimped up using Hubble data & Co.

https://www.starobserver.org/ap241005/



PS.: I also like the core in infrared ,-)

Click to view full size image

Original data: NASA/ESA (SST) jac berne (flickr)

What's true? That the Astrobin image really is the same as the APOD image, just manipulated in some way?

I am very sure that the image in the center area was manipulated.
However, it is not possible to determine with what data.

I also do not know why a different image appears on mirrored APOD pages.
I suspect that the originally planned image was the one that you also found from the author.

AVAO wrote: ↑Mon Oct 07, 2024 9:22 pm

johnnydeep wrote: ↑Mon Oct 07, 2024 8:56 pm

AVAO wrote: ↑Mon Oct 07, 2024 8:45 pm


Well I think that's true, whatever led to a version being mistakenly shown that was pimped up using Hubble data & Co.

https://www.starobserver.org/ap241005/



PS.: I also like the core in infrared ,-)

Click to view full size image

Original data: NASA/ESA (SST) jac berne (flickr)

What's true? That the Astrobin image really is the same as the APOD image, just manipulated in some way?

I am very sure that the image in the center area was manipulated.
However, it is not possible to determine with what data.

I also do not know why a different image appears on mirrored APOD pages.
I suspect that the originally planned image was the one that you also found from the author.

Ah. I see: the Astrobin image is the same one you found at https://www.starobserver.org/ap241005/, which seems like it's trying to be a mirror of the APOD, but the APOD image is different. Hmm.

Hey Zendae, thank you for linking that paper, that is really interesting to me, I'm going to be absorbed in that and related literature for a little while, thank you very much.

And haha Johnny Deep I agree, it does seem incomprehensible to me, maybe it is FRS or some other such abbreviation, but it could also be that Messier actually had multiple middle names. He was born while France had a king, and he died after France had gone through the purging process and become a Republic free from from the evils of monarchy. And then I will also say that in many monogram styles, the last name goes in the middle, and the middle names go at the end, so there's no way to know bass from ackwards. And one of his middle names was definitely Joseph, so the J's make sense.

Clear skies.

johnnydeep wrote: ↑Sun Oct 06, 2024 1:16 pm

florid_snow wrote: ↑Sun Oct 06, 2024 2:51 am ...
Also, Johnny Deep, the weird inscription you noticed was just a popular way of doing fancy cursive for your own name used at the time. Search "fancy monograms from history" to learn more. It's basically his initials with fancy cursive jibberish. A notable lover of history who continued this questionably decorative style for monograms was JRR Tolkein, and his kids also sign their names this way to this very day. If you can get one of their signatures in a book of his, it becomes very valuable.

Yeah, but, Tolkien's monogram is comprehensible. The name here is Charles Messier, with initials C.M. There's no middle name as far as I can find. So what the heck letters are supposed to be in this decorative monogram? I see "M" at the start, and "R" at the end, and maybe a huge "C" right after the "
M". I can also justify a "J" or two. So what letters are intended to be depicted here? "Messier, Charles, Fellow of the Royal Astronomical Society" or ... something?


messier monogram.jpg



In contrast, here are some comprehensible monograms:


sample fancy monograms.jpg