Click here for a full resolution image
Just for fun, I borrowed color data from the National Optical Astronomy Observatory (http://www.noao.edu/outreach/aop/observers/m104.html) and combined it with my luminance data to create a colorized M104 Credit for the color data goes to Morris Wade/Adam Block/NOAO/AURA/NSF
Click here to see the color image
Designations: M104 - Sombrero Galaxy, NGC4594
Visual
Magnitude: 8.0
Size: 8.7
x 3.5
Distance: 65 million light years
Discoverer: Pierre
Mechain, 1781
Visual Description: Picturesque M104 is an enigma. In the 1920s Edwin Hubble began classifying spiral galaxies based on the sizes of their central bulge relative to their arms. A galaxy such as M74 in Pisces, for example, has a very tight nuclear region and wide-sweeping spiral arms. M96 is on the other side of the spectrum, with a large bulge but relatively insignificant arms. Like M96, Ml04 displays a dominant central bulge in long-exposure photographs, but this nearly edge-on system also shows a preponderance of interstellar gas and dust, which is characteristic of a more evolved spiral galaxy, somewhere between M96 and M74 in the classification scheme. Another quizzical finding was made by Vesto Slipher of Lowell Observatory, who in 1913 became the first astronomer to detect rotation in a galaxy other than our own. By studying the spectrum of M104, he deduced that not only was the galaxy receding from us at 700 miles per second, but its disk was actually rotating: one side was moving toward us while the other side was moving away from us.
You can find the Sombrero Galaxy, as M104 is aptly called, hovering about 5 degrees northeast of Eta Corvi, just across the border in Virgo. Although it is some 20° south of the Virgo Cloud of galaxies, the Sombrero is nonetheless probably an outlying member of that group. Astronomers now believe that the galaxy is receding from us as at more than 600 miles per second and that it is extremely far away- 65 million light years. Some aficionados would prefer that the Messier catalogue end with this stunning object, perhaps feeling that the six subsequent objects (M105-M110) are visually anticlimactic by comparison. So, how does M104 look in a telescope?
Through the 4-inch, low power shows the galaxy as just a tiny oval glow that begs for more magnification. And, indeed, switching to medium power makes a dramatic difference. The galaxy displays a brilliant core that seems to illuminate the surrounding oval shroud from within, like a distant bonfire seen through a thick fog. A long, bright, needlelike extension runs straight across the major axis of the oval. The sharpness of this line reveals the position of the telltale dark lane, the edge of the Mexican hat's brim. It's quite remarkable to see such detail in a galaxy with only a glance.With time the brilliant dome over the northern part of the core appears to be straddled by faint condensations, one on either side. The core is the brightest feature of the three, followed by the western knot, and then the eastern one. With averted vision the eastern portion of the Sombrero's brim breaks up and flares into a wide brushstroke of light, which shines more brilliantly than the western portion of the brim. Every now and then the lashlike dust lane wafts into view. High power should reveal the full secrets of these glimmering visions. I find the galaxy looks best at 130 x, when it changes from a misty brew of suggestions into a galaxy with tightly wound spiral arms and clumps of unresolved starlight. Most surprising is that high power shows the nucleus shining with a yellow light. I have found no other reference to this.
The most challenging details lie in the southern portion of the halo, where a faint dome of light connects to the dark lane. Now switch to low power to see if you can discern a soft light enveloping the entire system. With high power can you resolve the galaxy's individual arms - crescents of light and dark that seem to ripple away from the core? With a little imagination these crescents can help you see the galaxy in three dimensions, like Saturn and its rings when they are nearly parallel to our line of sight. Few objects in the heavens allow users of small telescopes such an interesting visual perspective.
Image Processing: The image was processed with CCDStack and Photoshop CS2
Telescope: TMB
152mm APO refractor
Focal Length:
1200 mm
Mount: Takahashi
NJP
Camera: SBIG
ST10XME
Exposure:
18 10-minute exposures (3 hours total)
Autoguider:
SBIG ST402ME
The Visual description of the M104 Galaxy was writen by Steven James O'Meara in the book "The Messier Objects" by Stephen James O'Meara. Page. 269-271. ISBN number 0-521-55332-6.
Copyright(c) 2007 Doug Sanqunetti. All rights reserved
Doug's
Images
