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When you turn off the stars . . .



 
 
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  #1  
Old February 1st 07, 06:29 AM posted to sci.astro.amateur
Larry G.
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Posts: 33
Default When you turn off the stars . . .

The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.

1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.

2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.

3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.

cheers,
Larry G.

--
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  #2  
Old February 1st 07, 07:11 AM posted to sci.astro.amateur
Shawn
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Posts: 125
Default When you turn off the stars . . .

Larry G. wrote:
The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.

1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.

2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.


Interesting. How many galaxies are in the data base for each cluster?


3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.


Could this be due to areas where dust in the Milky Way blocks our view?


Shawn
  #3  
Old February 1st 07, 08:11 AM posted to sci.astro.amateur
Hardocks
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Posts: 7
Default When you turn off the stars . . .



"Larry G." wrote:

The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.

1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.

2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.

3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.

cheers,
Larry G.

--
Your mind is a terrible thing to waste - TURN OFF YOUR TV!

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I wouldnt jump to conlcusions based on one glimpse of the
whisker on the beast.



  #4  
Old February 1st 07, 11:49 AM posted to sci.astro.amateur
Larry G.
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Posts: 33
Default When you turn off the stars . . .

On Thu, 01 Feb 2007 00:11:39 -0600, Shawn
wrote:

Larry G. wrote:
The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.
1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.
2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.


Interesting. How many galaxies are in the data base for each cluster?


I'm not sure. I believe I was only looking at those with NGC
numbers. So, the answer would be in the thousands.

3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.


Could this be due to areas where dust in the Milky Way blocks our view?


I suspect the obscuring dust lies mainly within the general
band of the Milky Way, and is not much present outside the
galactic disc.

Cheers,
Larry G.

Shawn




--
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  #5  
Old February 1st 07, 12:59 PM posted to sci.astro.amateur
[email protected]
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Posts: 43
Default When you turn off the stars . . .

On Feb 1, 6:29 pm, "Larry G." wrote:
The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.

1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.


That seems odd. I would suspect that the periodic ones would be
orbiting near the ecliptic. The C/ ones I would expect to be randomly
distributed. Certainly the notable C/2006 P1 doesn't appear to be
aligned to either ecliptic or Milky Way.


2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.


Well they are collectively the Virgo cluster. The specific shape might
be an artifact of the projection method the software is using.


3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.


Do you know what database the software is using? NGC + IC

Bill



cheers,
Larry G.

--
Your mind is a terrible thing to waste - TURN OFF YOUR TV!

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  #6  
Old February 1st 07, 05:14 PM posted to sci.astro.amateur
Larry G.
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Posts: 33
Default When you turn off the stars . . .

On Thu, 01 Feb 2007 05:59:27 -0600, wrote:

On Feb 1, 6:29 pm, "Larry G." wrote:
The other night, I fired up an old copy of Distant Suns 5.1.
I was playing around with the settings, when I started noticing
a few interesting phenomena, when I turned off most of the stars,
and looked at the whole hemisphere at a time.

1. Most of the comets (of the six or eight default loaded)
seem to orbit within 10-20 degrees of the Milky Way.


That seems odd. I would suspect that the periodic ones would be
orbiting near the ecliptic. The C/ ones I would expect to be randomly
distributed. Certainly the notable C/2006 P1 doesn't appear to be
aligned to either ecliptic or Milky Way.


Yes, there was one or two that weren't obviously aligned.
If I had been thinking, I would have turned on the orbit
path visibility to see what sort of alignment was actually there.


2. The galaxies of Virgo, Coma B. and Canes V. seemed to
form a separate disc, similar to our Milky Way.


Well they are collectively the Virgo cluster. The specific shape might
be an artifact of the projection method the software is using.


I had the FOV zoomed out to see an entire hemisphere at a time.
I could rotate the FOV and the clumpy/disc-band pattern
remained consistent.

Perhaps the Virgo cluster is aligned along a more-or-less
linear boundary between two or three different void-bubbles
in the cosmic foam.


3. And there were vast streches of sky in which there were
relatively few cataloged galaxies. This echoes the findings
of a cosmological "foam" structure to the distribution of matter
on a very large scale.


Do you know what database the software is using? NGC + IC


Yes, I believe these are part of Distant Suns 5.1.

Cheers,
Larry G.

Bill



cheers,
Larry G.

--
Your mind is a terrible thing to waste - TURN OFF YOUR TV!

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--
Your mind is a terrible thing to waste - TURN OFF YOUR TV!

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  #7  
Old February 1st 07, 06:37 PM posted to sci.astro.amateur
Greg Crinklaw
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Posts: 886
Default When you turn off the stars . . .

Larry G. wrote:
I had the FOV zoomed out to see an entire hemisphere at a time.
I could rotate the FOV and the clumpy/disc-band pattern
remained consistent.

Perhaps the Virgo cluster is aligned along a more-or-less
linear boundary between two or three different void-bubbles
in the cosmic foam.


Sorry Larry, but you can't see the "cosmic foam" in looking at only the
brighter galaxies. The bright galaxies are the ones nearby, and it just
isn't a sufficient sample. Even with my SkyTools, which can plot over a
million galaxies on a single chart, such structure is only at best
hinted at. The other problem is that once you have enough galaxies in
your sample the close ones overlap the far ones, and unless you have a
means of separating them by distance you aren't really going to see the
structure. That is why this structure was only first revealed by deep
redshift surveys.

Also, any orientation with respect you the Milky way for your small
sample of comets is just coincidence. The orbits of comets have been
studied statistically and except for the periodic comets (which have had
their orbits perturbed by planets) their orientations are random.

Clear skies,
Greg

--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)

SkyTools: http://www.skyhound.com/cs.html
Observing: http://www.skyhound.com/sh/skyhound.html
Comets: http://www.skyhound.com/sh/comets.html

To reply take out your eye
  #8  
Old February 1st 07, 07:19 PM posted to sci.astro.amateur
William C. Keel
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Posts: 40
Default When you turn off the stars . . .

Greg Crinklaw wrote:
Larry G. wrote:
I had the FOV zoomed out to see an entire hemisphere at a time.
I could rotate the FOV and the clumpy/disc-band pattern
remained consistent.

Perhaps the Virgo cluster is aligned along a more-or-less
linear boundary between two or three different void-bubbles
in the cosmic foam.


Sorry Larry, but you can't see the "cosmic foam" in looking at only the
brighter galaxies. The bright galaxies are the ones nearby, and it just
isn't a sufficient sample. Even with my SkyTools, which can plot over a
million galaxies on a single chart, such structure is only at best
hinted at. The other problem is that once you have enough galaxies in
your sample the close ones overlap the far ones, and unless you have a
means of separating them by distance you aren't really going to see the
structure. That is why this structure was only first revealed by deep
redshift surveys.



Among NGC galaxies, you may well be seeing the elongation/flattening
of the Local Supercluster, roughly centered on the Virgo cluster.
Gerard de Vaucouleurs was almost alone for years in claiming
this as evidence for structure on a scale larger than obvious
clusters. He even defined a coordinate system aligned with this
"supergalactic plane" (which runs almost perpendicular to the
Milky Way plane), in which you can find positions
transformed at, for instance, ned.icpa.caltech.edu. The visibility
of this clump in galaxy catalogs owes a lot to the relatively
lwoer-density areas around it in most directions, which reduces
the foreground-background clutter than Greg mentioned.

Bill Keel

Bill Keel
  #9  
Old February 1st 07, 07:50 PM posted to sci.astro.amateur
Tom Polakis
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Posts: 49
Default When you turn off the stars . . .

On Feb 1, 11:19 am, "William C. Keel" wrote:
Among NGC galaxies, you may well be seeing the elongation/flattening
of the Local Supercluster, roughly centered on the Virgo cluster.
Gerard de Vaucouleurs was almost alone for years in claiming
this as evidence for structure on a scale larger than obvious
clusters. He even defined a coordinate system aligned with this
"supergalactic plane" (which runs almost perpendicular to the
Milky Way plane)...



Larry,

I think Bill's answer is correct that you are seeing the nearby
galaxies along the Supergalactic Plane. If you can, change the
magnitude limits until you find the optimal setting, and the string of
galaxies from Ursa Major down though southern Virgo show up nicely. I
have shown this effect to others using desktop planetarium software.
The relative dearth of nearby galaxies in the Autumn sky compared to
the Spring sky is a result of our position in the Local Supercluster.

As for the comet orientations, I'm sure that if you used a large
enough sample of orbits, you'd find that their inclinations do not
have a preferred orientation.

Tom

  #10  
Old February 2nd 07, 04:38 AM posted to sci.astro.amateur
Larry G.
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Posts: 33
Default When you turn off the stars . . .

On Thu, 01 Feb 2007 12:50:24 -0600, Tom Polakis
wrote:

On Feb 1, 11:19 am, "William C. Keel" wrote:
Among NGC galaxies, you may well be seeing the elongation/flattening
of the Local Supercluster, roughly centered on the Virgo cluster.
Gerard de Vaucouleurs was almost alone for years in claiming
this as evidence for structure on a scale larger than obvious
clusters. He even defined a coordinate system aligned with this
"supergalactic plane" (which runs almost perpendicular to the
Milky Way plane)...



Larry,

I think Bill's answer is correct that you are seeing the nearby
galaxies along the Supergalactic Plane. If you can, change the
magnitude limits until you find the optimal setting, and the string of
galaxies from Ursa Major down though southern Virgo show up nicely. I
have shown this effect to others using desktop planetarium software.
The relative dearth of nearby galaxies in the Autumn sky compared to
the Spring sky is a result of our position in the Local Supercluster.

As for the comet orientations, I'm sure that if you used a large
enough sample of orbits, you'd find that their inclinations do not
have a preferred orientation.

Tom


Thanks Tom, Bill, and Greg.
I did realize that the Virgo Supercluster was probably involved,
and thought its roughly linear distribution to be curious.
As for whether the voids around the cluster were cosmic or just
local variations is something I'd be willing to debate, mostly
for the sake of better understanding.

I've recently read an introductory book on Fractal Geometry.
A fractal is any pattern in which a magnified view of a smaller
portion strongly resembles the larger set. Having voids appear
among local / bright galaxies triggered this association, and
I still wonder if the cosmic foam isn't a true fractal phenomenon
much like so many other phenomena - lightening flashes, river
tributaries, star patterns, etc.

Thanks again, all.

Cheers,
Larry G.



--
Your mind is a terrible thing to waste - TURN OFF YOUR TV!

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