Astrophoto: Sagittarius Wide Field View
Written by Fraser Cain
Around midnight this time of year it's possible to witness the fires that smolder at our galaxy's core. Northern star gazers can see this by looking to the south, just above the horizon. Folks in the southern hemisphere should look closer overhead. Regardless, it's a view that should not be missed, if possible. This picture offers a tantalizing close-up that's part of the scene.
On any given night of the year the Milky Way is visible at least during parts of the evening. If you are fortunate to be in a relatively dark place, the glow from its billion individual suns blend their light into a chorus that can be mistaken for a cloud reflecting city lights when in fact you are usually just seeing our galaxy's extremities. We have an edge on view of our galaxy. No one alive and for a long time to come will have a different vantage point. We are not near the center nor are we at the edge of our barred island universe. We inhabit a minor arm, named after Orion, located about half way toward the middle of our galaxy's disk.
We live in a universe of galaxies. Ours, called the Milky Way, is only special because it's our home. If you have the opportunity to view the galactic center with your own eyes from a dark site, it's a scene you will long remember. Viewing the Milky Way is a study in enormity. Consider that the Moon is only slightly over a light second away and the Sun about eight light minutes distant. Their separation from us has an impact on their apparent size, however, since either can be eclipsed by the end of your thumb. But the Moon would almost span Australia and the Sun would hold about 1.3 million Earths. Now compare that to the heart of the Milky Way when you see it- the center is located 26,000 light years away towards the southern constellation of Sagittarius. This is about 820 trillion times further than the Moon, yet our Galaxy's central bulge appears wider than ten stacked moons and its arms extend from horizon to horizon. Our perspective is similar to cosmic plankton inside a galactic whale.
Between us and the heart of our Galaxy, lies many wonders that are much closer, such as those visible in this telescopic picture. Hanging in front of our galaxy's central star clouds, in the upper right, is the Trifid Nebula and below it floats the Lagoon. Each of these are stellar nurseries where new stars are born.
The Trifid was cataloged by the 18th century French comet hunter, Charles Messier, as M20 so that he would avoid mistaking it as a comet during his endless night time searches. M20 is located about 5,000 light years toward our galactic center. The hydrogen gas within this nebula gives it a distinctive red glow; the blue hues are from dust reflecting light emanating from nearby bright, new stars. The area is also awash in the debris of ancient supernovas.
Messier designated the Lagoon Nebula as M8 and it is also about 5,000 lights years distant. Like M20, its red color comes from abundant hydrogen gas. M8 is about 100 light years from end to end- this cloud of gas and dust is huge!
This scene also captures many other nebula and an open cluster of stars slightly above M20. Most of these places can be glimpsed with binoculars or a small telescope if you are far from city lights.
Tom Davis took this beautiful wide angle picture at the end of May this year from his imaging site in Inkdom, Idaho. The image required almost four and a half hours of exposure time. Slightly more than half of this was taken through a special deep red filter that accentuates the light from hydrogen gas in deep space.
Do you have photos you'd like to share? Post them to the Universe Today astrophotography forum or email them, and we might feature one in Universe Today.
Written by R. Jay GaBany
Filed under: Astrophotos
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