Explanation: This fifteen degree wide field of view stretches across the crowded starfields of Sagittarius toward the center of our Milky Way galaxy. In fact, the center of the galaxy lies near the right edge of the rich starscape and eleven bright star clusters and nebulae fall near the center of the frame. All eleven are numbered entries in the catalog compiled by 18th century cosmic tourist Charles Messier. Achieving celebrity status for skygazers, M8 (Lagoon), M16 (Eagle), M17 (Omega), and M20 (Trifid) show off the telltale reddish hues of emission nebulae associated with star forming regions. But also eye-catching in small telescopes are star clusters in the crowded region; M18, M21, M22, M23, M25, and M28. Broader in extent than the star clusters themselves, M24 is actually a cloud of the Milky Way's stars thousands of light-years long, seen through a break in the galaxy's veil of obscuring dust. You can put your cursor over the image (or click here) for help identifying Messier's eleven.
"Charles Messier used over a dozen telescopes during his career but his favorite was a 7.5 inch 104x Gregorian reflector. Later when the apochromatic refractor became available he utilized several 3.5 inch 120x apochromatics. "
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Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 6:50 am
by Ann
Boomer12k wrote:
ta152h0 wrote:How big a telescope did Mr Messier have available to him ?
"Charles Messier used over a dozen telescopes during his career but his favorite was a 7.5 inch 104x Gregorian reflector. Later when the apochromatic refractor became available he utilized several 3.5 inch 120x apochromatics. "
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Thanks for that info, Boomer12k. Very interesting. We should probably bear in mind, too, that Mr. Messier enjoyed very dark skies.
M24 is hugely interesting. It is, as was said in the caption of today's APOD, an opening in the permeating dust clouds that allows us a glimpse of what a spiral arm of the Milky Way may look like from a distance. The much better known Baade's Window is an opening in the dust that allows us to see a portion of the bulge of the Milky Way. The color contrast between the silver-blue spiral arm of M24 and the yellow bulge of our galaxy is so interesting.
Ann
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 10:21 am
by starsurfer
From yesterday's clue, I expected to see M11, the Wild Duck Cluster.
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 10:56 am
by neufer
Click to play embedded YouTube video.
.
starsurfer wrote:
From yesterday's clue, I expected to see M11, the Wild Duck Cluster.
"Charles Messier used over a dozen telescopes during his career but his favorite was a 7.5 inch 104x Gregorian reflector. Later when the apochromatic refractor became available he utilized several 3.5 inch 120x apochromatics. "
It is worth remembering that larger telescopes don't produce brighter images, they merely allow one to operate at a higher magnification before the image starts becoming dimmer. Most Messier objects are fairly large, and are typically viewed at low magnification. Most are quite apparent with nothing more than binoculars. (That said, all of his telescopes were too small to properly take advantage of 100x magnification, meaning at those magnifications he was seeing substantially dimmed images compared with their naked eye brightness. Good thing he had those dark skies.)
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 4:08 pm
by Beyond
Heh, most of the dark skies we have now, are when the storm clouds roll in.
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 4:13 pm
by ta152h0
I remember ST Helens The birds were really confused
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 4:22 pm
by Lordcat Darkstar
Ann wrote:
Boomer12k wrote:
ta152h0 wrote:How big a telescope did Mr Messier have available to him ?
"Charles Messier used over a dozen telescopes during his career but his favorite was a 7.5 inch 104x Gregorian reflector. Later when the apochromatic refractor became available he utilized several 3.5 inch 120x apochromatics. "
:---[===} *
Thanks for that info, Boomer12k. Very interesting. We should probably bear in mind, too, that Mr. Messier enjoyed very dark skies.
M24 is hugely interesting. It is, as was said in the caption of today's APOD, an opening in the permeating dust clouds that allows us a glimpse of what a spiral arm of the Milky Way may look like from a distance. The much better known Baade's Window is an opening in the dust that allows us to see a portion of the bulge of the Milky Way. The color contrast between the silver-blue spiral arm of M24 and the yellow bulge of our galaxy is so interesting.
Ann
Actually if I remember correctly Messier observed from the observatory in Paris. If you consider all of the oil street lamps and the smoke from cooking fires, he probably didn't have all that good of seeing conditions. I vaugly remember reading an article that explained just how bad it was back then but sadly I don't remember which magazine it was in
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 6:22 pm
by Ann
Lordcat Darkstar wrote:
Actually if I remember correctly Messier observed from the observatory in Paris. If you consider all of the oil street lamps and the smoke from cooking fires, he probably didn't have all that good of seeing conditions. I vaugly remember reading an article that explained just how bad it was back then but sadly I don't remember which magazine it was in
I most certainly don't know enough about this topic to contradict you. However, I looked up what kind of street lamps there might have been in Paris during Charles Messier's lifetime. Messier lived between 1730 and 1817, and during that time there were apparently no street lights in Paris.
http://en.wikipedia.org/wiki/Gas_lighti ... s_lighting wrote:
A "thermolampe" using gas distilled from wood was patented in 1799, whilst German inventor Friedrich Winzer (Frederick Albert Winsor) was the first person to patent coal-gas lighting in 1804.
In 1801, Phillipe Lebon of Paris had also used gas lights to illuminate his house and gardens, and was considering how to light all of Paris. In 1820, Paris adopted gas street lighting.
Ann
Re: APOD: Messier's Eleven (2013 Jul 12)
Posted: Fri Jul 12, 2013 6:32 pm
by ta152h0
Love it when APOD spurs on knowledge, whether it is new or historical. Sometimes I wonder myself if any simple innocuous sounding questions spur a vast search and discoveries. the monolith lives on, ....Dave.