A glimpse to the night sky
by Oriol Lehmkuhl & Ivette Rodriguez
This pair of galaxies, that form a physical pair, are located at about 12 million light years and constitute a great view on small scopes. The pair is the center of a group of galaxies encompassing the northern circumpolar constellations of Ursa Major and Camelopardis (see location below).
M81, the greatest of the two, has an apparent magnitude of 6.9 and its one of the largest galaxies that can be seen from the Earth. M81 is interacting with M82 causing tidal forces that actually are deforming the latter. Regarding M82, scientist believe that a violent outburst may have occurred within the galaxy about 1.5 million years ago.
These galaxies were discovered by Johann Elert Bode in December, 1774. They were photographed for first time in March, 1899. Of course in those days nothing was known about the faint nebulae that can be seen in the photo above.
In fact, this faint nebulosity of diffuse gas and dust clouds, was discovered a few year ago in December, 2004. It has been discovered by Steve Mandel an amateur astronomer, who coined the name of Integrated Flux Nebula (IFN). These clouds are located high above the plane toward the North Galactic Pole of our galaxy and it seems that can be found also around the Southern pole. But, what it most amazing is that these nebulae are not illuminated by the radiation of a particular star but for the integrated flux of all the stars in our Milky Way.
M81 and M82 wide field
12/03/09
Capturing this faint nebula was not easy, in fact it required more than 14 h of image acquisition. We needed 3 nights for acquiring the whole data. We drove more than 200 km from our house, looking for some dark location, away from the light pollution of the region near Barcelona city. But after all, we think it worth the effort, our instruments were capable of capture the IFN.
Our objective, when we began with this image was to bring out as much as possible of the IFN and at the same time, to preserve the small details in the galaxies. As for the color balance, we have used the center of M81 as reference, assuming that its core is white, and after that, it has been slightly corrected assuming that the integral flux of the whole image is pure white, considering that the objects in it emits in the continuum.
Image data:
Lens: FSQ106 f/5
Camera: QSI 540ws CCD camera
Exposure time: 7 h in 900'' subexps for L, 4:30 h in 600'' for RGB and 3 h in 900'' subexps for Ha
Filters: Baader filters
Location: Ager, Spain
Date: February 21st and 28th, 2009
Source: www.universetoday.com
