Astronomy Picture of the Day 6-20-02

NASA ^ | 6-20-02 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2002 June 20

Bright Galaxy M81
Credit & Copyright: Robert Gendler

Explanation: Big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth. This superbly detailed view reveals its bright nucleus, grand spiral arms and sweeping cosmic dust lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane runs straight through the disk, below and right of the galactic center, contrary to M81's other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 (aka NGC 3031) has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years.

[petuniasevan]

The photographer used a CCD camera at the prime focus of a 12.5" reflector telescope.
He made images as follows:

120 minute b/w detail scan.
10 minute red filter scan.
10 minute green filter scan.
20 minute blue filter scan.

By a technique known as "luminance layering" the photographer combined the images using Photoshop.
This gives the image detail, depth, and authentic hues.
For more information click the link:
robgendlerastropics

Get on the APOD PING list!

[petuniasevan]

APOD PING!

[RightWhale]

12-1/2" diameter is getting up into the professional range of telescope sizes. Or a serious amateur in a good location with appropriate viewing conditions. The photographer has put a fair amount of time into his set-up, and possibly some money as well, although money can be replaced with labor to a degree.

[petuniasevan]

That's true. I could go out and buy a Dobsonian "light bucket" relatively cheap, but it's useless for astrophotography.
As for a well-built, quality 12.5 inch Newtonian, it's just too big, heavy and ungainly for many people.
A Schmidt-Cassegrain or Matsukov will do beautifully, but we're talking some serious bucks here.
But hey! Got too much time and money? Here's a new wallet-slimming hobby!
Wish I could afford to do that, though...

[sleavelessinseattle]

I got to help do that digital spectum layering on the Triffid nebula
at Table Mountain two years ago...The difference in Detail is INCREDIBLE
You really felt like you were getting a feel for the distribution of elements
in the picture...whole regions would be Dark in Red and lit up in Blue or whatever.
Putting the images together was so easy thanks to the software...I wouldn't do
film astrophotography after seeing what the CCD can do and its just in its
INFANCY! Makes me want to go shoot out all the streetlamps in Seattle!!!
I'm glad people get to read about the technology behind these images BEAM P7...
Excellent POST!

[2Trievers]

Beautiful ... inspiring!

Humankind has not woven the web of life.
We are but one thread within it.
Whatever we do to the web, we do to ourselves.
All things are bound together.
All things connect.
~Chief Seattle~

[2Trievers]

From the Source of Sources ...

Winking star surrounded by embryonic solar system

Astronomers have found a young star with a dust cloud around it which may one day form a solar system like our own.

The cloud eclipses the star making it wink. It's the first time scientists have had a chance to study a structure like it.

It may help them understand how our own star and planet evolved.

Their view is so good they can see annual and even monthly changes.

The structure is thought to be just three million years old and 2,400 light years from the Earth.

Scientists led by William Herbst and Catrina Hamilton, of Wesleyan University in Connecticut, carried out the study into KH 15D.

The star is in the constellation of Monoceros and inhabits a nebulous region of space close to the famous Cone Nebula.

Observations made in the late 1990s tipped them off that this structure was different to others. Herbst said: "Basically, the star winked at us."

That is because it fades out every 48.3 days and stays faint for about 18 days. Material orbiting the star blocks its light out on this regular basis.

There are many examples of eclipsing binary stars but the length of the eclipse is unique in the case of KH 15D because only a collection of smaller objects surrounding the star can explain it.

[MeekOneGOP]

M81 bump! Thanks for adding me to the ping list!

[Joan912]

Gorgeous!

[headsonpikes]

I love these threads; they bring a sense of awe and wonder to my office for a moment!

I mean usually I just wonder why I came to work. ;^)