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View Full Version : PHOTO OF THE WEEK, NGC2336 in Cam


Jack Schmidling
April 20th 04, 03:59 PM
This week we have NGC2336 in Camelopardalis.

This giant spiral galaxy lies at a distance of about 96 million light
years. It is 178,000 light years across or about the same size as our
Milky Way.

js


--
Astronomy, Beer, Cheese, Gems, Sausage http://schmidling.netfirms.com

William Phillips
May 19th 04, 05:32 PM
Jack

The Milky Way is approximately 80,000 light years across (ignoring the
commonly quoted and incorrect figure of 100,000 ly and ignoring a few halo
stars and tenuous gas clouds).

[refer Bok and Bok "The Milky Way" 5th edition - p25 gives a value of 25kpc]

....so it must be TWICE the size of our Milky Way.........

"Jack Schmidling" > wrote in message
om...
> This week we have NGC2336 in Camelopardalis.
>
> This giant spiral galaxy lies at a distance of about 96 million light
> years. It is 178,000 light years across or about the same size as our
> Milky Way.
>
> js
>
>
> --
> Astronomy, Beer, Cheese, Gems, Sausage http://schmidling.netfirms.com

David Knisely
May 20th 04, 03:36 AM
William Phillips posted:

> The Milky Way is approximately 80,000 light years across (ignoring the
> commonly quoted and incorrect figure of 100,000 ly and ignoring a few halo
> stars and tenuous gas clouds).

The precise diameter of the Milky Way is not known. Like many other galaxies,
the edges are irregular and not well defined (and we can't really see the
"edge" very clearly even if there is a well-defined one due to our position in
the galaxy). There was even a broad "ring" of stars recently discovered in
the galactic plane nearly 120,000 light years from the galactic center. Thus,
estimates for its diameter range from around 75,000 to as much as 120,000
light years. This does *not* necessarily make the 100,000 light year figure
"incorrect", but merely one of many educated estimates for the size of the
galaxy. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

William Phillips
May 22nd 04, 06:37 AM
The precise diameter of the Milky Way is well known. There is nothing much
beyond 80,000 light years except some tenous gas and halo stars that merge
with the intergalactic medium. From Andromeda, the Milky Way disk would be
very clearly defined at this value.



"David Knisely" > wrote in message
...
> William Phillips posted:
>
> > The Milky Way is approximately 80,000 light years across (ignoring the
> > commonly quoted and incorrect figure of 100,000 ly and ignoring a few
halo
> > stars and tenuous gas clouds).
>
> The precise diameter of the Milky Way is not known. Like many other
galaxies,
> the edges are irregular and not well defined (and we can't really see the
> "edge" very clearly even if there is a well-defined one due to our
position in
> the galaxy). There was even a broad "ring" of stars recently discovered
in
> the galactic plane nearly 120,000 light years from the galactic center.
Thus,
> estimates for its diameter range from around 75,000 to as much as 120,000
> light years. This does *not* necessarily make the 100,000 light year
figure
> "incorrect", but merely one of many educated estimates for the size of the
> galaxy. Clear skies to you.
> --
> David W. Knisely
> Prairie Astronomy Club: http://www.prairieastronomyclub.org
> Hyde Memorial Observatory: http://www.hydeobservatory.info/
>
> **********************************************
> * Attend the 11th Annual NEBRASKA STAR PARTY *
> * July 18-23, 2004, Merritt Reservoir *
> * http://www.NebraskaStarParty.org *
> **********************************************
>
>

David Knisely
May 22nd 04, 07:08 AM
William Phillips posted:

> The precise diameter of the Milky Way is well known. There is nothing much
> beyond 80,000 light years except some tenous gas and halo stars that merge
> with the intergalactic medium. From Andromeda, the Milky Way disk would be
> very clearly defined at this value.

Ok, so who took you out in their trans-warp driven starship to view the area?
There is *no* fully-agreed upon value for the "well-known" diameter of the
Milky Way. There are only "estimates", ranging from 75,000 to over 120,000
light years. We know the distance from the sun to the galactic core far
better than we know the diameter of our galaxy.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************

William Phillips
May 24th 04, 11:06 AM
I think the values have been refined substantially over the last few
decades. Waller & Hodge confirms the 80,000 ly value, and indicates that the
halo extends out to 300,000 ly. Sure, they are only estimates, but would be
good to +/-10%

"David Knisely" > wrote in message
...
> William Phillips posted:
>
> > The precise diameter of the Milky Way is well known. There is nothing
much
> > beyond 80,000 light years except some tenous gas and halo stars that
merge
> > with the intergalactic medium. From Andromeda, the Milky Way disk would
be
> > very clearly defined at this value.
>
> Ok, so who took you out in their trans-warp driven starship to view the
area?
> There is *no* fully-agreed upon value for the "well-known" diameter of
the
> Milky Way. There are only "estimates", ranging from 75,000 to over
120,000
> light years. We know the distance from the sun to the galactic core far
> better than we know the diameter of our galaxy.
> --
> David W. Knisely
> Prairie Astronomy Club: http://www.prairieastronomyclub.org
> Hyde Memorial Observatory: http://www.hydeobservatory.info/
>
> **********************************************
> * Attend the 11th Annual NEBRASKA STAR PARTY *
> * July 18-23, 2004, Merritt Reservoir *
> * http://www.NebraskaStarParty.org *
> **********************************************
>
>
>

David Knisely
May 25th 04, 05:34 AM
William Phillips posted:

> I think the values have been refined substantially over the last few
> decades. Waller & Hodge confirms the 80,000 ly value, and indicates that the
> halo extends out to 300,000 ly. Sure, they are only estimates, but would be
> good to +/-10%

Can you cite the specific research paper where this value is stated and how
this alleged level of accuracy has been obtained? The "standard" diameter in
the literature appears to still be "approximately" 30 kpc (nearly 100,000
light years). I still have grave doubts that anyone could come to an estimate
which was accurate to even 30% (most star distances beyond those measurable by
trigonometric parallax are probably no more accurate than 20% to 30%). To say
that the diameter of our galaxy is known to within +/- 10% is ludicrous.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************