Starship Asterisk*

Spiral Galaxy NGC 3190 Almost Sideways

Explanation: Some spiral galaxies are seen almost sideways. NGC 3190, one such galaxy, is the largest member of the Hickson 44 Group, one of the nearer groups of galaxies to our own Local Group of galaxies. Pictured above, finely textured dust lanes surround the brightly glowing center of this picturesque spiral. Gravitational tidal interactions with other members of its group have likely caused the spiral arms of NGC 3190 to appear asymmetric around the center, while the galactic disk also appears warped. NGC 3190 spans about 75,000 light years across and is visible with a small telescope toward the constellation of the Lion (Leo).

<< Previous APOD

Discuss Any APOD

Next APOD >>

[/b]

It might just be the "crick" in my neck - but it seems as though the center of this Galaxy is dropped somewhat from where it should be.

discombobulated

Looks as though the dark dust lanes are dissolved toward the far side of the galaxy! Maybe they are hidden by the galaxies center? I think your right Ed; discombobulated!

I am just wondering if someone could drop a few words about the background galaxies visible in the upper left quadrant, are they member of any cluster? They seem to be so many.

Thomas
Hannover

Just out of curiosity, why doesn't our moon, our sun and the local group of what, 25 galaxies(?), have a name?
Could I volunteer the use of mine for the local group of galaxies, "Oyervides Group" just because i'm the first one to think about it. Surely with an infinite number of galaxies and groups and clusters of galaxies in the universe, there should be enough to go around for each and every citizens on earth today, 1000 times over!
Surely it would be far better and more dignified than using some of the names of astronimical objects I've seen in the past! Cat's Paw, Cat Eye, Seagull and the Duck, Witch Head, Rat's Tail, need I go on? When somebody looks at something and says, yeah, that ngc 2163 looks like a 'Horned Toad', how does that person's adjective stick? What gives that person a right to name anything and approved by some official body just because they happen to have the privilege of peering thru a billion dollar telescope and civilians don't?

It isn't just the "local group" -- it's the "Local Group". That's its name, though I agree it's not especially evocative. The gravitational center of the group is somewhere between the Milky Way and Andromeda, so maybe we could call our group the Andromeda Way group. (Licence plate slogan: It's our Way or the spaceway.)

Rob

JuanAustin wrote:Just out of curiosity, why doesn't our moon, our sun and the local group of what, 25 galaxies(?), have a name?

You mean Luna, Sol, and the Andromeda (or M31) Group? Actually the last one isn't really the name of the local group, but given that many galaxy groups are named for the dominant member (M101, M81, M51 Groups), that would probably be the name of the local group. Other naming conventions name the group after the constellation in which they are found (Sculptor, Leo, Draco Groups). I don't know that Luna and Sol are the official names of our moon and sun, but they have historically been used as names. Probably the official names are the Moon, the Sun, and the Local Group (notice the capitalization).

edit: Oops, I see Rob beat me to it. Historically, M31 has been considered the dominant member of the Local Group (Andromeda thought to be larger and more massive then the Milky Way), but recent studies suggest the Milky Way is more massive (and larger) than previously thought and M31 may not be so dominant.

So how do these names become official anyway?
i've seen some really bewildering ones for craters, nebulas especially and galaxies that just makes me scratch my head.
How do our friends in other countries deal with having to refer to something ridiculous that only an american in many instances would understand? Well, i'm claiming our local group or The Local Group, Andromeda Way, or whatever..., as mine! I would appreciate it if you would refer to it from now on as the "Oyervides Group".

JuanAustin wrote:So how do these names become official anyway?

Astronomical naming conventions
International Astronomical Union (IAU)

Do all galaxies rotate in the same direction? Could the Milky Way and the local group be rotating around some distant body so far away we can't perceive it?

katieM wrote:Do all galaxies rotate in the same direction? Could the Milky Way and the local group be rotating around some distant body so far away we can't perceive it?

It sounds like you are confusing rotation and revolution. Galaxies rotate around their own axes, and the direction they rotate is largely random with respect to other galaxies (although there are galaxy groups where the rotational axes are somewhat aligned). You are asking if galaxies might be orbiting some distant mass, and the answer to that is no. Distant galaxies are moving away from each other, and some galaxy groups share a degree of common motion. But there's no indication of someplace in the Universe that everything else is orbiting.

Last night, I spent some time observing the Spring Globulars (M13,M92,M3,M53 etc.) and I am wondering. Are there globulars in this image.

Does anyone know why objects such as this galaxy are referred to as being found towards particular constellations? Clearly, most such objects are well beyond any of the stars which form the constellation, so why not say "beyond", or, simply, "in"? We all know that constellations are essentially two-dimensional projections, so "in" would be quite appropriate, but saying "towards" Leo seems to imply an erroneous three-dimensional relationship.

Macropus wrote:Does anyone know why objects such as this galaxy are referred to as being found towards particular constellations? Clearly, most such objects are well beyond any of the stars which form the constellation, so why not say "beyond", or, simply, "in"? We all know that constellations are essentially two-dimensional projections, so "in" would be quite appropriate, but saying "towards" Leo seems to imply an erroneous three-dimensional relationship.

I don't think I've heard anybody say an object is "towards" any constellation. The term that is used is "in", which is correct. What this APOD caption seems to be saying is that to see the galaxy, you need to aim your telescope towards Leo, which is reasonable usage.

I don't think I've heard anybody say an object is "towards" any constellation. The term that is used is "in", which is correct. What this APOD caption seems to be saying is that to see the galaxy, you need to aim your telescope towards Leo, which is reasonable usage.

OK - here are just a few from past APODs, and there are many more:

NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices)
NGC 6217, which spans about 30,000 light years across and can be found toward the constellation of the Little Bear (Ursa Minor).
The North America Nebula (NGC 7000) spans about 50 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).

It's no big deal - it would just be nice to avoid being potentially misleading.

Macropus wrote:OK - here are just a few from past APODs, and there are many more:

NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices)
NGC 6217, which spans about 30,000 light years across and can be found toward the constellation of the Little Bear (Ursa Minor).
The North America Nebula (NGC 7000) spans about 50 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).

It's no big deal - it would just be nice to avoid being potentially misleading.

Well, the usage is a little odd, but I don't really think it's misleading. "Toward" does mean "in the direction of", after all. So the usage isn't wrong, even if it's not common. I guess it's just an idiosyncrasy of that particular caption writer.

Chris Peterson wrote:

Macropus wrote:OK - here are just a few from past APODs, and there are many more:

NGC 4676 lies about 300 million light-years away toward the constellation of Bernice's Hair (Coma Berenices)
NGC 6217, which spans about 30,000 light years across and can be found toward the constellation of the Little Bear (Ursa Minor).
The North America Nebula (NGC 7000) spans about 50 light years and lies about 1,500 light years away toward the constellation of the Swan (Cygnus).

Well, the usage is a little odd, but I don't really think it's misleading. "Toward" does mean "in the direction of", after all. So the usage isn't wrong, even if it's not common. I guess it's just an idiosyncrasy of that particular caption writer.

• Constellation, n. [F. constellation, L. constellatio.] A cluster or group of fixed stars, OR
  division of the heavens within whose imaginary outline, as traced upon the heavens, the group is included.

So...is a constellation to be thought of as a cluster of stars OR a division of the heavens?

If the former then "beyond" is appropriate; if the latter then "in" is appropriate.

However, "toward" can be said to be appropriate for both cases.

• "The constellations seem to have been almost purposely named and delineated
  to cause as much confusion and inconvenience as possible." - Sir J. Herschel.

neufer wrote:So...is a constellation to be thought of as a cluster of stars OR a division of the heavens?

Both- it just depends on context. When talking about the asterism, it is the grouping of stars that is being referred to. When an object is said to be in a certain constellation, it is a region of the sky (which may be quite far from the associated asterism).

Chris Peterson wrote:

neufer wrote:So...is a constellation to be thought of as a cluster of stars OR a division of the heavens?

Both- it just depends on context. When talking about the asterism, it is the grouping of stars that is being referred to. When an object is said to be in a certain constellation, it is a region of the sky (which may be quite far from the associated asterism).

Then APOD is quite correct in saying "toward" rather than "in" or "beyond."

neufer wrote: Then APOD is quite correct in saying "toward" rather than "in" or "beyond."

Yeah, that's what I said. The usage is correct, but it's also unusual (which is presumably a source of some confusion).