APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Comments and questions about the APOD on the main view screen.
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Chris Peterson
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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by Chris Peterson » Fri Sep 14, 2012 11:09 pm

quigley wrote:If earth was a planet in either galaxy M60 or NGC4647, what would the night sky look like? What percentage of the night sky would be filled with the dense stars of the neighboring galaxy, assuming that your attitude of observation would be toward that galaxy?
The sky would probably look similar to the Milky Way, but over the whole sky, not just a band. Basically, you'd just have a brighter sky background, and over that you'd see a somewhat richer star field than we see here.
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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by starsurfer » Sat Sep 15, 2012 12:07 pm

Chris Peterson wrote:
starsurfer wrote:I heartily agree with you Ann! While many professional images have stunning resolution, a few suffer from a lack of colour information due to the number of filters used or assignment of colours.
"Color" is rarely of scientific interest or value. In fact, most images made with a pair of filters contain more information than images made with broad RGB filters. The latter will present an image that approximates what the eye might see were it more sensitive, but that type of color tends to be very ambiguous with respect to the mechanisms that produce it. Professional images are very commonly made using just two filters, because the intensity ratio between properly chosen bands provides critical information about physical mechanisms. Sometimes more filters are used, of course, but given the value of observational time on large instruments, the minimum number of filters necessary to extract the intended information will normally be used.
Of course colour isn't particularly useful from a scientific point of view but I was referring to the aesthetic sense. The fact that observing time is rarer than vibranium (*cough* Captain America reference *cough") and very expensive is exactly why researchers only get data in a particular set of filters, usually this is only 2 filters and an image produced with just 2 filters produces a bicolour appearance. The main reason that particular filters are used are to isolate specific lines and provide amazing detail to be revealed in narrow lines that isn't visible in general filters. I'm particularly fond of OIII and it's amazing the wide variety of stellar phenomenon that can be revealed with OIII such as symbiotic outflows or bowshocks around cataclysmic variables!

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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by neufer » Sat Sep 15, 2012 12:25 pm

starsurfer wrote:
Of course colour isn't particularly useful from a scientific point of view but I was referring to the aesthetic sense.

The fact that observing time is rarer than vibranium...
http://en.wikipedia.org/wiki/Vibranium wrote:
Image
<<Vibranium was first deposited on Earth by a meteorite 10,000 years ago. The first documented discovery of Vibranium was during a human expedition to Antarctica. This particular isotope of Vibranium was dubbed "Anti-Metal" due to its property of dissolving other metals.

A different variety of Vibranium found in Wakanda absorbs soundwaves and other vibrations, including kinetic energy. It was discovered by the Wakandan king T'Chaka, father of the Black Panther T'Challa. To protect this resource, he concealed his country from the outside world. By occasionally selling off minute quantities of the metal, T'Chaka funded his country's education. Because of this, Wakanda is one of the world's most technologically advanced nations. During the early 1940s, a small amount of Wakandan Vibranium came into the possession of the scientist Myron MacLain. He tried to combine Vibranium with iron to form a new tank armor, but was unable to fuse the elements. One morning, he found that the two materials had bonded on their own in an unknown manner. The ultra-resilient alloy was used to create Captain America's shield. McClain worked for decades to duplicate the accident. During a trial in the 1960s, he developed the virtually indestructible metal adamantium.

Over the years, many have tried to obtain or affect the mound of Vibranium at Wakanda, but for the most part Wakanda has kept it safe, and become quite powerful in the process. During their Secret Invasion of Earth, the Skrulls assumed the identity of S.H.I.E.L.D. Agents and enslaved natives of the Savage Land to mine Anti-Metal. They also invaded Wakanda. The Wakandans repelled the attack successfully. When Wakanda is politically taken over by the xenophobic Desturi, they grant Dr. Doom access to the country's Vibranium vaults. Fearing Doom will use it to amplify his mystical energies, T'Challa activates a failsafe he had developed that rendered all processed Vibranium inert.>>
Art Neuendorffer

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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by owlice » Sat Sep 15, 2012 12:29 pm

I have to say I get a little tired of the complaints about scientific images being... well, scientific.
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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by starsurfer » Mon Sep 17, 2012 12:31 pm

owlice wrote:I have to say I get a little tired of the complaints about scientific images being... well, scientific.
Scientific images are awesome! :D :D :D

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Re: APOD: Elliptical M60, Spiral NGC 4647 (2012 Sep 14)

Post by Anthony Barreiro » Mon Sep 17, 2012 8:57 pm

quigley wrote:If earth was a planet in either galaxy M60 or NGC4647, what would the night sky look like? What percentage of the night sky would be filled with the dense stars of the neighboring galaxy, assuming that your attitude of observation would be toward that galaxy?
Hi Quigley. I'm catching up on the past few days of apod's, not sure if you're still checking this particular discussion thread, but you raised an interesting question.

M60 is 54 million light years from us; NGC4647 is 63 million light years from us. If I remembered more trigonometry I might be able to calculate the distance between the two galaxies, but let's assume it's approximately 9 million light years. There are a number of spiral galaxies within 10 million light years of us here in the Milky Way. You can't see them with the naked eye; through a telescope they show up as faint fuzzy patches of light. Under good observing conditions an experienced observer can detect spiral structure in the fuzziness.

There are some nearby dwarf elliptical galaxies, but the nearest big ones (like M60 itself) are in the Virgo cluster, more than 50 million light years away. I suppose that a big bright elliptical galaxy 9 million light years away might look something like the core of the Andromeda Galaxy appears from 2.5 million light years away from Earth, a faint fuzzy patch visible to the naked eye under dark conditions.
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