APOD: Messier 101 (2023 Jun 02)

[APOD Robot]

Messier 101

Explanation: Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic spans about 40,000 light-years across the central region of M101 in one of the highest definition spiral galaxy portraits ever released from Hubble. The sharp image shows stunning features of the galaxy's face-on disk of stars and dust along with background galaxies, some visible right through M101 itself. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.

<< Previous APOD

This Day in APOD

Next APOD >>

[Ann]

Messier 101. Image Credit: NASA, ESA, CFHT, NOAO; Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

---

3-armed background galaxy behind M101!

What I like best about today's APOD is the lovely little three-armed galaxy behind M101 (at 10 o'clock)!

Ann

[Rauf]

Messier 101. Image Credit: NASA, ESA, CFHT, NOAO; Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

---

3 armed background galaxy in M101 APOD November 27 2021.png

3-armed background galaxy behind M101!

What I like best about today's APOD is the lovely little three-armed galaxy behind M101 (at 10 o'clock)!

Ann

Lovely! It's like a little spider trying to play with pinwheel
I tried to find it's name, or it's distance but I wasn't successful

[Ann]

Messier 101. Image Credit: NASA, ESA, CFHT, NOAO; Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

---

3 armed background galaxy in M101 APOD November 27 2021.png

3-armed background galaxy behind M101!

What I like best about today's APOD is the lovely little three-armed galaxy behind M101 (at 10 o'clock)!

Ann

Lovely! It's like a little spider trying to play with pinwheel
I tried to find it's name, or it's distance but I wasn't successful

I haven't been able to find it either.

So here is a challenge for everyone:

Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann

[AVAO]

Messier 101. Image Credit: NASA, ESA, CFHT, NOAO; Acknowledgement - K.Kuntz (GSFC), F.Bresolin (U.Hawaii), J.Trauger (JPL), J.Mould (NOAO), Y.-H.Chu (U. Illinois)

---

3 armed background galaxy in M101 APOD November 27 2021.png

3-armed background galaxy behind M101!

What I like best about today's APOD is the lovely little three-armed galaxy behind M101 (at 10 o'clock)!

Ann

Lovely! It's like a little spider trying to play with pinwheel :
I tried to find it's name, or it's distance but I wasn't successful :

I haven't been able to find it either.

So here is a challenge for everyone:


3 armed background galaxy in M101 APOD November 27 2021.png


Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann

No such exists. I think we should name these "Ann's three-armed spiral galaxy"

[Ann]

Lovely! It's like a little spider trying to play with pinwheel :
I tried to find it's name, or it's distance but I wasn't successful :

I haven't been able to find it either.

So here is a challenge for everyone:


3 armed background galaxy in M101 APOD November 27 2021.png


Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann

No such exists. I think we should name these "Ann's three-armed spiral galaxy"

I'll take it!

Ann

[De58te]

The first sentence in the explanation got me to thinking. Of all the entries in the Charles Messier's famous catalog, Which entry WOULD be considered one of the very least (famous or beautiful?) As it's said if somebody comes in first place in a race, then by definition somebody else must come in last place.

[Ann]

The first sentence in the explanation got me to thinking. Of all the entries in the Charles Messier's famous catalog, Which entry WOULD be considered one of the very least (famous or beautiful?) As it's said if somebody comes in first place in a race, then by definition somebody else must come in last place.

How about M48?

Open cluster M48 in Hydra. Image credit: Jim Mazur.

---

Wikipedia wrote about M48:

This grouping was discovered by Charles Messier in 1771, but there is no cluster precisely where Messier indicated; he made an error, as he did with M47. The value that he gave for the right ascension matches, however, his declination is off by five degrees.

Or M47?

Open cluster Messier 47 in Puppis. Credit: NOIRLab / NSF / AURA

---

Wikipedia wrote about M47:

There is no cluster in the position indicated by Messier, which he expressed in terms of its right ascension and declination with respect to the star 2 Puppis. However, if the signs (+ and −) he wrote are swapped, the position matches. Until this equivalency was found, M47 was considered a lost Messier Object.

Or M91?

M91 was long considered a missing object in the Messier catalog. Image credit: NASA, ESA, and J. Lee (California Institute of Technology)

---

Wikipedia wrote about M91:

It is about 63 million light-years away from our galaxy. It was the last of a group of eight "nebulae" – the term 'galaxy' only coming into use for these objects once it was realized in the 20th century that they were extragalactic – discovered by Charles Messier in 1781. It is the faintest object in the Messier catalog, with an apparent magnitude of 10.2.

As a result of a bookkeeping error by Messier, M91 was for a long time one of the few missing entries in the Messier catalog, not matching any known object in the sky.

Or M102?

NGC 5866. NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

---

Wikipedia wrote about M102:

Messier 102 (also known as M102) is a galaxy listed in the Messier Catalogue that cannot be unambiguously identified. Its original discoverer Pierre Méchain retracted his discovery two years after publication and said that it was a duplicate observation of Messier 101. Later historical evidence favors that M102 is actually the galaxy NGC 5866, although other galaxies have been suggested as possible identities. The National Aeronautics and Space Administration (NASA) considers it to be the same as NGC 5866.

No really, M40 takes the cake as the least of all Messier objects!

Optical double star M40, the least of all Messier objects! Credit: Reevesastronomy at English Wikipedia

---

Wikipedia wrote about M40 (and yes, Winnecke 4 is the same as M40:

Winnecke 4 (also known as Messier 40 or WNC 4) is an optical double star consisting of two unrelated stars in a northerly zone of the sky, Ursa Major.

The pair were discovered by Charles Messier in 1764 while he was searching for a nebula that had been reported in the area by Johannes Hevelius. Not seeing any nebulae, Messier catalogued this apparent pair instead.
...

Burnham calls M40 "one of the few real mistakes in the Messier catalog," faulting Messier for including it when all he saw was a double star, not a nebula of any sort.

Ann

[orin stepanek]

I got (your connection is not secure on Three urls:) I guess they
weren't important!
I thought this was the pinwheel; but I had to read to last sentence to
verify!

[zendae]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

[zendae]

Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann
[/quote]


No designation, but at least this little ditty exists. Someone else likes it too.

https://www.flickr.com/photos/geckzilla ... lepictures

[Ann]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

Two pinwheels.png (7.3 KiB) Viewed 6656 times

That's right, there are two of them!

Ann

[Ann]

Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann

No designation, but at least this little ditty exists. Someone else likes it too.

https://www.flickr.com/photos/geckzilla ... lepictures

Lovely! But are they the same galaxy? They don't look quite the same to me.

Ann

[bystander]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

M101 is formally known as the Pinwheel Galaxy. M33 is formally designated as the Triangulum Galaxy.

M83 is the Southern Pinwheel Galaxy.

[Chris Peterson]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

M101 is formally known as the Pinwheel Galaxy. M33 is formally designated as the Triangulum Galaxy.

M83 is the Southern Pinwheel Galaxy.

There are no "formal" names for any galaxies. Just unofficial usage, and M33 is sometimes called the Pinwheel Galaxy. Which isn't wrong, just confusing. In catalog compilations (like SIMBAD) these names are listed as "historical" or "common" for reference purposes, but have no IAU formal recognition.

[johnnydeep]

Can you find a designation for the lovely three-armed spiral galaxy behind M101?

Ann

No designation, but at least this little ditty exists. Someone else likes it too.

https://www.flickr.com/photos/geckzilla ... lepictures

Lovely! But are they the same galaxy? They don't look quite the same to me.

3 armed spiral APOD 2 June 2023.png

3 armed spiral Hubble Geck.png

Ann

I think it's an "artists impression" via enhancement of the original using other info:

An illustration of a three armed galaxy based on a real one only visible as a faint fuzzy in the background of one of Hubble's images. The original Hubble image of the galaxy looks like this. We might never see a better picture of it and I wanted to try an illustration. I used textures and other background galaxies from the dataset of MCG+07-33-027. Many small details were hand painted, such as the little pink clouds of H-alpha.

[johnnydeep]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

Two pinwheels.png

Click to view full size image

That's right, there are two of them!

Ann

And that pair of course reminds me of this pair, "near" the Sombrero galaxy:

Original image, with the "pair" near the bottom edge at 7 o'clock:

Click to view full size image

[ PS - hey, did you know that you can use someone else's uploaded image file in a img2 tag, like I did above with Ann's image download/file.php?id=47564 from her post? ]

[Ann]

No designation, but at least this little ditty exists. Someone else likes it too.

https://www.flickr.com/photos/geckzilla ... lepictures

Lovely! But are they the same galaxy? They don't look quite the same to me.

3 armed spiral APOD 2 June 2023.png

3 armed spiral Hubble Geck.png

Ann

I think it's an "artists impression" via enhancement of the original using other info:

An illustration of a three armed galaxy based on a real one only visible as a faint fuzzy in the background of one of Hubble's images. The original Hubble image of the galaxy looks like this. We might never see a better picture of it and I wanted to try an illustration. I used textures and other background galaxies from the dataset of MCG+07-33-027. Many small details were hand painted, such as the little pink clouds of H-alpha.

I think their shapes are too different:

Ann

[Ann]

Are there two Pinwheel Galaxies, M101 and M33?

From Astronomy.com

"The Local Group’s third-largest member, the Pinwheel Galaxy (M33), resides in the constellation Triangulum. It is only about one-tenth the size of the Andromeda Galaxy and the Milky Way."

Two pinwheels.png

Click to view full size image

That's right, there are two of them!

Ann

And that pair of course reminds me of this pair, "near" the Sombrero galaxy:

Click to view full size image

Original image, with the "pair" near the bottom edge at 7 o'clock:

Click to view full size image

[ PS - hey, did you know that you can use someone else's uploaded image file in a img2 tag, like I did above with Ann's image download/file.php?id=47564 from her post? ]

Indeed, Johnny, it is possible to use someone else's uploaded image file in an img2 tag! I do it a lot.

Thanks for posting the lovely pair of background galaxies behind M104! There are so many great-looking background galaxies out there. A favorite of mine is the little round, barred thing behind M51. I'm posting two versions of it:

Background galaxy behind M51 Giacomo Pro.png (19.67 KiB) Viewed 6532 times

Background galaxy behind M51 esplaobs.png (46.32 KiB) Viewed 6532 times

Unless that is really a foreground planetary nebula? What do you think?

Ann

[johnnydeep]

That sure looks like a barred spiral behind M51 (do barred ellipticals exist?) - perhaps with an active galactic nucleus - to me! Where can I find that galaxy in the context of a larger image of M51? So far I have not been able to. Is it in this one, for example? (too big to post with an img tag):

https://cdn.spacetelescope.org/archives ... c0506a.jpg

[ From https://esahubble.org/images/heic0506a/ ]

[johnnydeep]

Lovely! But are they the same galaxy? They don't look quite the same to me.

3 armed spiral APOD 2 June 2023.png

3 armed spiral Hubble Geck.png

Ann

I think it's an "artists impression" via enhancement of the original using other info:

An illustration of a three armed galaxy based on a real one only visible as a faint fuzzy in the background of one of Hubble's images. The original Hubble image of the galaxy looks like this. We might never see a better picture of it and I wanted to try an illustration. I used textures and other background galaxies from the dataset of MCG+07-33-027. Many small details were hand painted, such as the little pink clouds of H-alpha.

I think their shapes are too different:


Two 3 armed spirals.png

Two 3 armed spiral galaxies annotated.png

Ann

Maybe. Plus, where'd that bright nearby star go?" The linked-to pic at the Geckzilla flickr page doesn't even mention what foreground galaxy it's behind, though it points to https://www.flickr.com/photos/geckzilla/7789411670/ as providing additional details. Is it in that pic of the Starburst Galaxy?

[Ann]

That sure looks like a barred spiral behind M51 (do barred ellipticals exist?) - perhaps with an active galactic nucleus - to me! Where can I find that galaxy in the context of a larger image of M51? So far I have not been able to. Is it in this one, for example? (too big to post with an img tag):

https://cdn.spacetelescope.org/archives ... c0506a.jpg

[ From https://esahubble.org/images/heic0506a/ ]

You can't find it in the ESA/Hubble image.

Here it is:

M51 and background galaxy.
Credit: Giacomo Pro.

Ann

[johnnydeep]

That sure looks like a barred spiral behind M51 (do barred ellipticals exist?) - perhaps with an active galactic nucleus - to me! Where can I find that galaxy in the context of a larger image of M51? So far I have not been able to. Is it in this one, for example? (too big to post with an img tag):

https://cdn.spacetelescope.org/archives ... c0506a.jpg

[ From https://esahubble.org/images/heic0506a/ ]

You can't find it in the ESA/Hubble image.

Here it is:

M51 and background galaxy Giacomo Pro.png

M51 and background galaxy.
Credit: Giacomo Pro.

Ann

Ah - thanks.

[VictorBorun]

Tried and failed to place this galaxy between the Local Sheet and Virgo Cluster.

the Local Sheet

---

Wiki does show all the 3 object in one map, here is my clip:

...

Click to view full size image 1 or image 2

To my eye these labels are too large to relate with galaxies.
But when I try to hang the Local Sheet map over, it fails:

[VictorBorun]

by the way, wiki's label
"Centaurus A/M86 Group 11.9 Mly"
must be wrong…

my bad, wiki label read M83

Corrected my mistake in images on my previous comment. How do I delete this outdated comment now?