APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

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APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by APOD Robot » Thu Sep 02, 2021 4:06 am

Image M51: The Whirlpool Galaxy

Explanation: Find the Big Dipper and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (top), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the eye, deep images like this one reveal its striking colors and galactic tidal debris.

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Ann » Thu Sep 02, 2021 5:19 am

Good old Whirlpool Galaxy and a very nice APOD! :D

M51-SL14-RGB-196-Final-cC_1024[1].png
M51 and NGC 5195. Credit: Josep M. Drudis
M51 NGC 5195 IC 4278 annotated.png

1) NGC 5195 was almost certainly a disk galaxy before it encountered M51, but the tidal interaction with the spiral galaxy has wrecked tidal chaos with NGC 5195's disk. Note the beige color of the scattered disk. NGC 5195 was to all accounts and purposes an all-yellow galaxy, with nothing but, at best, extremely small-scale star formation in it.

2) Don't know about you, but this looks like a dust fountain or a dust jet from the center of NGC 5195 to me.

3) The graceful morphology of M51 has undoubtedly been enhanced by its interaction with NGC 5195. Both its main arms may have been elongated by this interaction.

4) The are particularly high amounts of pink nebulas and star formation near "kinks" in the arms of M51.


5) There is a fantastic little background galaxy, IC 4278, to the east of NGC 5195. Note that the galaxy seems to have a disk or rather a ring, a long bar, and two bright blue regions of star formation at the ends of the bar.

IC4278 is slightly - mind you, slightly - similar to NGC 1512. Both galaxies clearly have bars and rings. But the bar of IC 4278 has no brightening or swelling in the center, and the star formation at the ends of the bar is bight and vigorous indeed.

Ann
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Last edited by Ann on Thu Sep 02, 2021 2:38 pm, edited 1 time in total.
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Alnitak » Thu Sep 02, 2021 11:40 am

Presumably you meant that IC4278 is slightly similar to NGC1512, Ann?
Does anyone know how far apart M51 and NGC5195 are?

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by orin stepanek » Thu Sep 02, 2021 12:25 pm

M51-SL14-RGB-196-Final-cC_1024.png
A beautiful Galaxy with an interrupter nearby! just my opinion!
Kinda looks like merging has already began! 8-)
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Chris Peterson » Thu Sep 02, 2021 1:01 pm

APOD Robot wrote:
Thu Sep 02, 2021 4:06 am
Find the Big Dipper and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.
You don't even need a telescope. This bright object is easy even in small binoculars (yes, I know that binoculars are just small, handheld telescopes).
Chris

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by E Fish » Thu Sep 02, 2021 1:28 pm

Chris Peterson wrote:
Thu Sep 02, 2021 1:01 pm
APOD Robot wrote:
Thu Sep 02, 2021 4:06 am
Find the Big Dipper[/url] and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.
You don't even need a telescope. This bright object is easy even in small binoculars (yes, I know that binoculars are just small, handheld telescopes).
Okay, that makes me feel a little stupid. I've never been able to see it in a telescope and I've looked for it before. I was hoping that maybe I just didn't have a good enough telescope but apparently it's all human error. Maybe once all the forest fire smoke is gone, I'll give it another try.

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Chris Peterson » Thu Sep 02, 2021 1:39 pm

E Fish wrote:
Thu Sep 02, 2021 1:28 pm
Chris Peterson wrote:
Thu Sep 02, 2021 1:01 pm
APOD Robot wrote:
Thu Sep 02, 2021 4:06 am
Find the Big Dipper[/url] and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.
You don't even need a telescope. This bright object is easy even in small binoculars (yes, I know that binoculars are just small, handheld telescopes).
Okay, that makes me feel a little stupid. I've never been able to see it in a telescope and I've looked for it before. I was hoping that maybe I just didn't have a good enough telescope but apparently it's all human error. Maybe once all the forest fire smoke is gone, I'll give it another try.
Certainly, reasonably dark skies, free of smoke and haze, are required. If you haven't seen it in a telescope, it's only because you haven't pointed it in the right place. Even under light polluted skies it's an easy fuzzy blob through any telescope.
Chris

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Ann » Thu Sep 02, 2021 2:38 pm

Alnitak wrote:
Thu Sep 02, 2021 11:40 am
Presumably you meant that IC4278 is slightly similar to NGC1512, Ann?
Does anyone know how far apart M51 and NGC5195 are?
Eh. Yes, I did. :oops:

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by neufer » Thu Sep 02, 2021 3:52 pm

Alnitak wrote:
Thu Sep 02, 2021 11:40 am

Does anyone know how far apart M51 and NGC5195 are?
  • About 40,000 light years.
https://en.wikipedia.org/wiki/NGC_5195 wrote:
<<NGC 5195 and the Whirlpool Galaxy compose one of the most noted interacting galaxy pairs in astronomy. The two galaxies are listed in the Atlas of Peculiar Galaxies as one of several prominent examples of a spiral galaxy with a companion galaxy.[6] The system was also the subject of very early theoretical investigations into galaxy interactions. The two galaxies are connected by a dust-rich tidal bridge. The dust in this tidal bridge can be seen silhouetted against the center of NGC 5195. This demonstrates that NGC 5195 appears to lie behind the Whirlpool Galaxy. The encounter has significantly enhanced the spiral structure of M51.

In January 2016, BBC science reporter Jonathan Webb said, "Astronomers have spotted two huge waves of gas being 'burped' by the black hole at the heart of a nearby galaxy. The swathes of hot gas, detected in X-ray images from NASA's Chandra space telescope, appear to be sweeping cooler hydrogen gas ahead of them. This vast, rippling belch is taking place in NGC 5195 - a small, neglected sibling of the 'Whirlpool Galaxy', 26 million light years away. That makes it one of the closest black holes blasting gas in this way". He added, "The findings, presented at the 227th meeting of the American Astronomical Society (AAS) in Florida, are a dramatic example of 'feedback' between a supermassive black hole and its host galaxy". Webb's report cited Marie Machacek, co-author of the study from the Harvard–Smithsonian Center for Astrophysics (CFA), as saying, "We think that feedback keeps galaxies from becoming too large […] But at the same time, it can be responsible for how some stars form. This shows that black holes can create, not just destroy."
https://stargazerslounge.com/topic/260979-how-far-to-small-galaxies-near-m51/ wrote:
<<After plugging in the numbers, my colleague and I have settled on a figure of 230 million light years to IC4278. Why is this of interest? Well, I am currently holding an exhibition of astrophotography in Marlborough and have been merrily telling everyone that the most distant object on display is M51, at 23 million light years away. However, in the picture, just below M51, is a faint smudge, definitely not a star, definitely a Galaxy... IC4278, now estimated, with thanks to your help, to be 230 million light years away, ten times more distant. That's neat. However, the really beautiful coincidence is the value for the galaxy's red shift, 0.01672. Why is that beautiful? The dialling code for Marlborough is 01672 !!!!>>
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Fred the Cat » Thu Sep 02, 2021 4:10 pm

E Fish wrote:
Thu Sep 02, 2021 1:28 pm
Chris Peterson wrote:
Thu Sep 02, 2021 1:01 pm
APOD Robot wrote:
Thu Sep 02, 2021 4:06 am
Find the Big Dipper[/url] and follow the handle away from the dipper's bowl until you get to the last bright star. Then, just slide your telescope a little south and west and you'll come upon this stunning pair of interacting galaxies, the 51st entry in Charles Messier's famous catalog.
You don't even need a telescope. This bright object is easy even in small binoculars (yes, I know that binoculars are just small, handheld telescopes).
Okay, that makes me feel a little stupid. I've never been able to see it in a telescope and I've looked for it before. I was hoping that maybe I just didn't have a good enough telescope but apparently it's all human error. Maybe once all the forest fire smoke is gone, I'll give it another try.
I've struggled too finding it with binoculars and a small telescope. I was out with my camera (click photo for high res) last month.
IMG_2055 (2).JPG
Then a pesky satellite came by.
IMG_2084 (2).JPG
How much might light pollution or seeing conditions make finding M51 more difficult? :?
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by VictorBorun » Thu Sep 02, 2021 4:23 pm

Ann wrote:
Thu Sep 02, 2021 5:19 am
2) Don't know about you, but this looks like a dust fountain or a dust jet from the center of NGC 5195 to me.
Ann
M51-SL14-RGB-196-Final-cC-.jpg
to my eye there is a dusty outer part of one of Whirlpool's arm that NGC 5195 is piercing through moving ← (leftwards) and away from us.
The severed half of that part of the arm is less constrained by Whirlpool's gravitation and is kicked more easily; therefore it's displaced away from us and is frontlighted by NGC 5195's core. The part of the arm that is still connected is bent and seen close to our line of sight; it's backlighted by NGC 5195's core and thus looks bright, almost orange.
Now NGC 5195 must be no-gas heavy-cored elliptical dwarf however strange it sounds.
How can a dwarf galaxy end up without gas?
Was it kicked and slingshotted in the past (maybe by the the same Whirlpool here?)
Or does it possess a super-heavy central black hole that made some flashes of accretion in the past, generating harsh spherical plasma waves and blowing up a gasless bubble?
Or is NGC 5195 a superfast ram stripped of its gas by cluster's ram wind?
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Ann » Thu Sep 02, 2021 5:16 pm

VictorBorun wrote:
Thu Sep 02, 2021 4:23 pm
Ann wrote:
Thu Sep 02, 2021 5:19 am
2) Don't know about you, but this looks like a dust fountain or a dust jet from the center of NGC 5195 to me.
Ann
M51-SL14-RGB-196-Final-cC-.jpg
to my eye there is a dusty outer part of one of Whirlpool's arm that NGC 5195 is piercing through moving ← (leftwards) and away from us.
The severed half of that part of the arm is less constrained by Whirlpool's gravitation and is kicked more easily; therefore it's displaced away from us and is frontlighted by NGC 5195's core. The part of the arm that is still connected is bent and seen close to our line of sight; it's backlighted by NGC 5195's core and thus looks bright, almost orange.
Now NGC 5195 must be no-gas heavy-cored elliptical dwarf however strange it sounds.
How can a dwarf galaxy end up without gas?
Was it kicked and slingshotted in the past (maybe by the the same Whirlpool here?)
Or does it possess a super-heavy central black hole that made some flashes of accretion in the past, generating harsh spherical plasma waves and blowing up a gasless bubble?
Or is NGC 5195 a superfast ram stripped of its gas by cluster's ram wind?
Bridge between M51 and NGC 5195 annotated.png

This is what I can see in the image:

1: One arm of M51, passing in front of NGC 5194.

2: Dust being ejected from the core of NGC 5195.

3: A dusty jet being emitted by NGC 5195.

I don't think NGC 5195 is entirely without gas. But the gas that it does possess is scattered "all over", not concentrated in certain regions where it might give rise to new stars. However, it is indeed likely that much of the gas it does have is concentrated near its core, because this is a phenomenon that we have seen in other mostly all "red and dead" galaxies.


The dusty inner disk is just a small part of galaxy NGC 4526, which is a galaxy mostly devoid of star formation. We see the phenomenon of dusty inner disks in other elliptical and lenticular galaxies too.


Ann
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by johnnydeep » Thu Sep 02, 2021 8:25 pm

I case anyone need a pic showing where M51 is in relation to the Big Dipper:

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by VictorBorun » Thu Sep 02, 2021 8:58 pm

Ann wrote:
Thu Sep 02, 2021 5:16 pm
This is what I can see in the image:
1: One arm of M51, passing in front of NGC 5194.
2: Dust being ejected from the core of NGC 5195.
3: A dusty jet being emitted by NGC 5195.
I don't think NGC 5195 is entirely without gas. But the gas that it does possess is scattered "all over", not concentrated in certain regions where it might give rise to new stars. However, it is indeed likely that much of the gas it does have is concentrated near its core, because this is a phenomenon that we have seen in other mostly all "red and dead" galaxies.
The dusty inner disk is just a small part of galaxy NGC 4526, which is a galaxy mostly devoid of star formation. We see the phenomenon of dusty inner disks in other elliptical and lenticular galaxies too.
Ann
To test if NGC 5194's core is concentric with a dusty ring I overlayed 24 μm far infra red image showing no dust and the true position of the core. I took it from wiki, shifted hue to red and made it a semi-transparent overlay.
Whirlpool.png
I admit now that there seems to be some dust concentric with the core of NGC 5194
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Last edited by VictorBorun on Fri Sep 03, 2021 1:06 am, edited 1 time in total.

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Chris Peterson » Thu Sep 02, 2021 11:12 pm

Fred the Cat wrote:
Thu Sep 02, 2021 4:10 pm
E Fish wrote:
Thu Sep 02, 2021 1:28 pm
Chris Peterson wrote:
Thu Sep 02, 2021 1:01 pm

You don't even need a telescope. This bright object is easy even in small binoculars (yes, I know that binoculars are just small, handheld telescopes).
Okay, that makes me feel a little stupid. I've never been able to see it in a telescope and I've looked for it before. I was hoping that maybe I just didn't have a good enough telescope but apparently it's all human error. Maybe once all the forest fire smoke is gone, I'll give it another try.
I've struggled too finding it with binoculars and a small telescope. I was out with my camera (click photo for high res) last month.
IMG_2055 (2).JPG
Then a pesky satellite came by.
IMG_2084 (2).JPG
How much might light pollution or seeing conditions make finding M51 more difficult? :?
I had no problem finding it from southern California, not far from L.A. under skies bright enough that the Big Dipper stood alone with no stars to speak of around it. M51 is really bright. Now, under bright skies it isn't going to look like much more than a fuzzy blob with little or no structure, but you can't miss it if you've got a scope on it. You might miss it with binoculars under those conditions. I usually find it easily by tracing down the last two stars of the handle, making a 90° turn, and going about half that distance again (basically, picturing a 30-60-90 triangle). At a moderately low power that should put in your eyepiece.
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Ann » Fri Sep 03, 2021 4:51 am

VictorBorun wrote:
Thu Sep 02, 2021 8:58 pm
Ann wrote:
Thu Sep 02, 2021 5:16 pm
This is what I can see in the image:
1: One arm of M51, passing in front of NGC 5194.
2: Dust being ejected from the core of NGC 5195.
3: A dusty jet being emitted by NGC 5195.
I don't think NGC 5195 is entirely without gas. But the gas that it does possess is scattered "all over", not concentrated in certain regions where it might give rise to new stars. However, it is indeed likely that much of the gas it does have is concentrated near its core, because this is a phenomenon that we have seen in other mostly all "red and dead" galaxies.
The dusty inner disk is just a small part of galaxy NGC 4526, which is a galaxy mostly devoid of star formation. We see the phenomenon of dusty inner disks in other elliptical and lenticular galaxies too.
Ann
To test if NGC 5194's core is concentric with a dusty ring I overlayed 24 μm far infra red image showing no dust and the true position of the core. I took it from wiki, shifted hue to red and made it a semi-transparent overlay. I admit now that there seems to be some dust concentric with the core of NGC 5194
Thank you for the overlay. The dust in the core of NGC 5195 is quite thin, so it wouldn't show up well in infrared images. (That's the deal with infrared images, after all: In many cases you can see through the dust.)


I have changed my mind about the last annotated image I posted:


I said previously that number 2 in my annotated image was dust from the core of NGC 5195. On closer inspection, I don't think so. Unlike the darker plume of dust to the right of it, it doesn't seem to originate from the core of NGC 5195, but from a location "above" it.

What is located "above" the core of NGC 5195 from our point of view? Well, the extended arm of M51 passing in front of NGC 5195 is a good candidate.

And note how the arm of M51 appears to "run out of steam" or at least "run ut of dust" at the exact point where we see the dust that I have labeled 2. We can see a blue star cluster above the point where the dust disappears, so clearly there was dust there before (as dust seems essential to concentrate and cool the gas to make it ripe for star formation). So what if that dust is really from the arm of M51? if so, what happened to the dust?

It is interesting to speculate that there just may have been an outburst, even a jet of some kind, from the core of of NGC 5195, that deflected the dust of the arm of M51.

I keep insisting that the darker brown dust plume really does look as if it originates from the core (or near the core) of NGC 5195.

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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by VictorBorun » Fri Sep 03, 2021 8:25 am

Ann wrote:
Fri Sep 03, 2021 4:51 am
number 2 doesn't seem to originate from the core of NGC 5195, but from a location "above" it.
What is located "above" the core of NGC 5195 from our point of view? Well, the extended arm of M51 passing in front of NGC 5195 is a good candidate.
And note how the arm of M51 appears to "run out of steam" or at least "run ut of dust" at the exact point where we see the dust that I have labeled 2. We can see a blue star cluster above the point where the dust disappears, so clearly there was dust there before (as dust seems essential to concentrate and cool the gas to make it ripe for star formation). So what if that dust is really from the arm of M51? if so, what happened to the dust?
It is interesting to speculate that there just may have been an outburst, even a jet of some kind, from the core of of NGC 5195, that deflected the dust of the arm of M51.
I keep insisting that the darker brown dust plume really does look as if it originates from the core (or near the core) of NGC 5195.

Ann
Can't resist to check if the two arms of Whirlpool's are in fact more similar than they seem because of NGC 5195's backlighting (that would suggest that NGC 5195 is deeply background or passing by swift and is just subtly affecting the shape of the upper Whirlpool's arm).

Here side by side are far IR images, showing no dust and therefore no backlighted dust. The first fragment shows the upper and the second is 180° rotated image of the lower arm:
Whirlpool upper.png
Whirlpool lower.png
It looks like the upper arm is stretched and straightened out. In 3d the upper arm may be not straightened out, but pulled away from us
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by VictorBorun » Fri Sep 03, 2021 8:51 am

and here is the upper Whirlpool's arm (left) and the 180° rotated image of the lower Whirlpool's arm (right) cut from APOD's post

Is the dust flowing rightward from the core of NGC 5195 in the background?
Or is it Whirlpool's dust frontlighted by the core of NGC 5195 — which must be piercing the arm then… and splitting it in two, one flowing rightward and the other upward? This second option looks absurd now.
Whirlpool upper 2.png
Whirlpool lower 2.png
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by Chris Peterson » Fri Sep 03, 2021 1:29 pm

Ann wrote:
Fri Sep 03, 2021 4:51 am
Thank you for the overlay. The dust in the core of NGC 5195 is quite thin, so it wouldn't show up well in infrared images. (That's the deal with infrared images, after all: In many cases you can see through the dust.)
We can see thin dust much better in IR bands than in visible ones. We use IR to detect the thinnest of dust regions.
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Re: APOD: M51: The Whirlpool Galaxy (2021 Sep 02)

Post by neufer » Fri Sep 03, 2021 5:32 pm

https://en.wikipedia.org/wiki/Clef wrote: <<A clef (from French: clef 'key') is a musical symbol used to indicate which notes are represented by the lines and spaces on a musical stave. When a clef is placed on a staff it assigns a particular pitch to one of the five lines, which in turn gives pitch value to the remaining lines and spaces.

The three clef symbols used in modern music notation are the G-clef, F-clef, and C-clef. Placing these clefs on a line fixes a reference note to that line—an F-clef fixes the F below middle C, a C-clef fixes middle C, and a G-clef fixes the G above middle C. In modern music notation, the G-clef is most frequently seen as treble clef (placing G4 on the second line of the stave), and the F-clef as bass clef (placing F3 the fourth line). The C-clef is mostly encountered as alto clef (placing middle C on the third line) or tenor clef (middle C on the fourth line). A clef may be placed on a space instead of a line, but this is rare.

The use of different clefs makes it possible to write music for all instruments and voices, regardless of differences in range. Using different clefs for different instruments and voices allows each part to be written comfortably on a stave with a minimum of ledger lines. To this end, the G-clef is used for high parts, the C-clef for middle parts, and the F-clef for low parts. Transposing instruments can be an exception to this—the same clef is generally used for all instruments in a family, regardless of their sounding pitch. For example, even the low saxophones read in treble clef.

The only G-clef still in use is the treble clef, with the G-clef placed on the second line. This is the most common clef in use and is generally the first clef learned by music students. For this reason, the terms "G-clef" and "treble clef" are often seen as synonymous. The treble clef was historically used to mark a treble, or pre-pubescent, voice part.

Instruments that use the treble clef include violin, flute, oboe, cor anglais, all clarinets, all saxophones, horn, trumpet, cornet, vibraphone, xylophone, mandolin, recorder, and bagpipe. Guitar also uses the treble clef, sounding an octave lower than written. Euphonium and baritone horn are sometimes treated as transposing instruments, using the treble clef and sounding a major ninth lower, and are sometimes treated as concert-pitch instruments, using bass clef. The treble clef is also the upper stave of the grand stave used for harp and keyboard instruments. Most high parts for bass-clef instruments (e.g. cello, double bass, bassoon, and trombone) are written in the tenor clef, but very high pitches may be notated in the treble clef. The viola also may use the treble clef for very high notes. The treble clef is used for the soprano, mezzo-soprano, alto, contralto and tenor voices. Tenor voice parts sound an octave lower and are often written using an octave clef or a double-treble clef.>>
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