APOD: A Milky Way Dawn (2014 Mar 29)

[APOD Robot]

A Milky Way Dawn

Explanation: As dawn broke on March 27, the center of the Milky Way Galaxy stood almost directly above the European Southern Observatory's Paranal Observatory. In the dry, clear sky of Chile's Atacama desert, our galaxy's dusty central bulge is flanked by Paranal's four 8 meter Very Large Telescope units in this astronomical fisheye view. Along the top, Venus is close to the eastern horizon. The brilliant morning star shines very near a waning crescent Moon just at the edge of one of the telescope structures. Despite the bright pairing in the east, the Milky Way dominates the scene though. Cut by dust lanes and charged with clouds of stars and glowing nebulae, the center of our galaxy sprawls across the darker zenith even as the deep blue sky grows brighter and buildings still glint in moonlight.

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[Guest]

Hello,

Is this picture taken looking back at the centre of the Milky Way Galaxy?

Thanks,

Den

[Chris Peterson]

Is this picture taken looking back at the centre of the Milky Way Galaxy?

Pretty close to it. The center of our galaxy is nearly overhead in the image.

[Ann]

A Milky Way dawn under.

Ann

[Boomer12k]

Neat...you can basically see it from end to end...


:---[===] *

[Nitpicker]

Neat...you can basically see it from end to end...


:---[===] *

Of course, from Earth, you can never see more than half (180°) of the Milky Way at any one time. In this image, the galaxy's backside is blocked by the Earth. (Not to mention that the core of the galaxy obscures everything on the far side of the core, in the so called observation shadow.)

[Guest]

is blocked by the Earth. (Not to mention

Not to mention all those scruffy buildings in the way ! Almost as cluttered as my site.
Shame, would have been a nice picture else

[Chris Peterson]

Of course, from Earth, you can never see more than half (180°) of the Milky Way at any one time.

That is sort of true, but misleading. At times and places you can see the entire length of the Milky Way, with the missing half being above or below the galactic equator, not a segment of galactic longitude.

[neufer]

---

Of course, from Earth, you can never see more than half (180°) of the Milky Way at any one time.

That is sort of true, but misleading. At times and places you can see the entire length of the Milky Way, with the missing half being above or below the galactic equator, not a segment of galactic longitude.

http://www.flickr.com/photos/jasonc66/9420934880/

http://www.flickr.com/photos/astro_andre/6799748616/

[quigley]

Will someone please answer the last question on yesterday's APOD discussion. I find all of the questions and answers so very interesting. Thanks!

[Guest]

Is this picture taken looking back at the centre of the Milky Way Galaxy?

Pretty close to it. The center of our galaxy is nearly overhead in the image.

Thanks Chris

[Nitpicker]

Of course, from Earth, you can never see more than half (180°) of the Milky Way at any one time.

That is sort of true, but misleading. At times and places you can see the entire length of the Milky Way, with the missing half being above or below the galactic equator, not a segment of galactic longitude.

If I had left out the "(180°)" it would have been better. Viewing the galaxy when its plane aligns with the local horizon is hardly ideal (all that scruffy atmosphere and hills, trees, buildings, etc).

[Chris Peterson]

If I had left out the "(180°)" it would have been better. Viewing the galaxy when its plane aligns with the local horizon is hardly ideal (all that scruffy atmosphere and hills, trees, buildings, etc).

Not ideal, but certainly possible. From my house, I've seen about 270° of the Milky Way when it's very close to lying on the horizon.

[ems57fcva]

There is something about the contrast in this image that reveals something interesting: There appear to be two dust lanes in this image. What appears to be the foreground dust land starts on the upper right side of the Milky Way. As it come to the central bulge area, it heads downward and around the bulge, and comes back to the plane of the galaxy on the other side. Another dust lane in the background goes across the central bulge of the Milky Way. This can also be seen in http://apod.nasa.gov/apod/ap140212.html (where the second dust lane is above the central bulge) if you know what you are looking for.

I take this to indicate the the Sun offset from the plan of the galaxy a ways. so that at its closest to us we are viewing the foreground dust lane from a different angle than the background one. Another possibility is that the Milky Way is warped like may other spiral galaxies are. This could even be a combination of the two.

[ta152h0]

can the souther cross be seen in this fisheye image ?

[alter-ego]

can the souther cross be seen in this fisheye image ?

Yes.

[alter-ego]

There is something about the contrast in this image that reveals something interesting: There appear to be two dust lanes in this image. What appears to be the foreground dust land starts on the upper right side of the Milky Way. As it come to the central bulge area, it heads downward and around the bulge, and comes back to the plane of the galaxy on the other side. Another dust lane in the background goes across the central bulge of the Milky Way. This can also be seen in http://apod.nasa.gov/apod/ap140212.html (where the second dust lane is above the central bulge) if you know what you are looking for.

I take this to indicate the the Sun offset from the plan of the galaxy a ways. so that at its closest to us we are viewing the foreground dust lane from a different angle than the background one. Another possibility is that the Milky Way is warped like may other spiral galaxies are. This could even be a combination of the two.

I believe that the answer is due to non-uniform matter distribution in the disk, maybe due to warping but not necessarily. The sun is currently considered to be <100 ly away from the galactic plane, and the average outer disk thickness is many thousands of light years. The perspective you're seeing is over 10's of thousands of light years. I think our displacement from the plane is too small to reveal the large structural differences in angle that you're referring to.

[Nitpicker]

Of course, from Earth, you can never see more than half (180&deg;) of the Milky Way at any one time.

If I had left out the "(180&deg;)" it would have been better. Viewing the galaxy when its plane aligns with the local horizon is hardly ideal (all that scruffy atmosphere and hills, trees, buildings, etc).

Not ideal, but certainly possible. From my house, I've seen about 270° of the Milky Way when it's very close to lying on the horizon.

Still less than half the Milky Way, just not by galactic longitude. And to see more than 180&deg; of the galactic plane (i.e. the great circle representing 0&deg; galactic latitude) you'd have to rely on atmospheric refraction, I think, and have a very good horizon.

[geckzilla]

Being on a mountain helps, too.

[alter-ego]

Of course, from Earth, you can never see more than half (180&deg;) of the Milky Way at any one time.

If I had left out the "(180&deg;)" it would have been better. Viewing the galaxy when its plane aligns with the local horizon is hardly ideal (all that scruffy atmosphere and hills, trees, buildings, etc).

Not ideal, but certainly possible. From my house, I've seen about 270° of the Milky Way when it's very close to lying on the horizon.

Still less than half the Milky Way, just not by galactic longitude. And to see more than 180&deg; of the galactic plane (i.e. the great circle representing 0&deg; galactic latitude) you'd have to rely on atmospheric refraction, I think, and have a very good horizon.

Everest panorama courtesy of Roddy Mackenzie (APOD 17 Apr 2011)
Sky background generated with Stellarium

Yes, that and some altitude. Coincidentally, Mt. Everest is not only the highest point on Earth but also the galactic pole is at its zenith (almost). Some time ago I created the panorama above. The high altitude and remote location provides dark skies, and on average (counting horizon dip and atmospheric refraction) one can see to -2°galactic latitude. The geographic heading and sky azimuth are accurate, but milky way brightness, sky brightness, and stellar magnitude limit were subjectively set.

[Nitpicker]

Yes, that and some altitude. Coincidentally, Mt. Everest is not only the highest point on Earth but also the galactic pole is at its zenith (almost). Some time ago I created the panorama above. The high altitude and remote location provides dark skies, and on average (counting horizon dip and atmospheric refraction) one can see to -2°galactic latitude. The geographic heading and sky azimuth are accurate, but milky way brightness, sky brightness, and stellar magnitude limit were subjectively set.

Very nice. Thanks.

[Ann]

Yes, very nice, thank you!

Ann

[alter-ego]

Very nice. Thanks.

Yes, very nice, thank you!

You are very welcome

[Nitpicker]

Being on a mountain helps, too.

So long as you are not surrounded by even higher mountains. I live on a small hill, in the middle of a valley surrounded by bigger hills.

[geckzilla]

Being on a mountain helps, too.

So long as you are not surrounded by even higher mountains. I live on a small hill, in the middle of a valley surrounded by bigger hills.

As if anyone would choose to interpret my statement in that way.