[AZ-Observing] Re: M101 for the month of May
- From: "Jimmy Ray" <jimmy_ray@xxxxxxx>
- To: <az-observing@xxxxxxxxxxxxx>
- Date: Sat, 26 May 2007 06:57:41 -0700
This article answers most of what I was looking for as far as the amount of
and effect of intergalactic dust on our ability to decern actual brightness,
distance, and color of objects at great distances:
"ISO proves that intergalactic space is dusty" - 1997
http://www.iso.esac.esa.int/outreach/esa_pr/in9737.htm
Aside from our our observing and imaging the universe throught a slightly
"dirty window pane", Galaxies appear to be quite the little dust producers.
Maybe burning hydrogen (followed by Helium, etc. etc.) isn't any cleaner
than us with fossil fuels...
Anyway, thanks Chris for a very stimulating image and comment...
Jimmy Ray
----- Original Message -----
From: "Jimmy Ray" <jimmy_ray@xxxxxxx>
To: <az-observing@xxxxxxxxxxxxx>
Sent: Friday, May 25, 2007 17:33
Subject: [AZ-Observing] Re: M101 for the month of May
Oooo, got burned for "over quoting" so look for a response coming out of the
blue sometime in the future.. (this one should make it with only the
pertainate details)
The article (Are spiral galaxies round?) along with Jenn's well articulated
response perfectly answer my first question. Jenn and Dan, Thank you very
much.
In the case of Chris's image, question two (dustiness) is still open...
Jimmy Ray
Jennifer,
There are three catalogs that list galactic inclinations cited in this
interesting article:
http://eo.ucar.edu/staff/dward/sao/dward604project.pdf
I haven't looked for any of those catalogs, but I assume they're available.
I stumbled across this article when I was looking for a formula to calculate
galactic inclination based on observed major and minor axes.
Dan Heim
> Chris,
>
> Another highly detailed photo but do you really think 10x better than your
> previous photos with your "old" camera. Definitely 100x better than a
> Brownie!
>
> I wonder to gravitational lensing--when there is a galaxy within the
obvious
> confines of the nearer galaxy, is it _always_ magnified by the
> gravitational lens? Would a camera still pick all of them up if they
weren't
> magnified by the closer galaxy?
>
> Jimmy,
> As for the inclination of M101 it's actually 17o, and yes, all spiral
> galaxies are round. There is a set formula to determine the inclination
> based on the length and width + a few degrees for what radio telescopes
> pick up beyond that. It's a bit counter-intuitive in that 0 degrees is
> perfectly face on and 90 degrees is an edge on. The Andromeda galaxy for
> example is inclined 77+degrees.
>
> Does anyone knows where to find a list of galaxy inclinations, even a
small
> list like for the M's would be great for a comparison.
>
>
> Chris,
> ...The brightest knot in the arms to the upper right of the nuclear region
> is NGC5462, an complex blue stellar association with a rim of red hydrogen
> around its energetic core. When we add the hydrogen data to this image,
the
> galaxy dynamics that will become visible here will be simply out of this
> world....
>
> Actually NGC 5462 is to the left of the nuclear region at about 9:30 with
an
> even brighter NGC 5461 just below it closer to the nucleus.
>
> Jenn.
>
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