Can you actaully see nebulae/clusters with your eyes?

[nexius]

I am really intrested in buying a telescope this will sound pretty bad but I was wondering if you could actaully see nebulae and clusters with your eyes. (Deep-Space Objects) Everything I have ever seen has been a picture on the net with like 6 hrs of exposure time from a camera. Im assuming we cant see that since it took so long to gather the light for the picture. With a powerful enough telescope though, can you really see it with your own eyes?

 

[billslugg]

Oh, Yeah! With a telescope you can see bunches of nebulae.<br />Even with the naked eye you can see the Andromeda nebula and the Large Magellanic Cloud and the Small Magellanic Cloud. (If you are far South enough for the two later) Beware though, when you get South of the Equator, all of the constellations are upside down! It fooled me for a while! <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[willpittenger]

If you have a powerful enough telescope, you can see almost anything. Some exceptions: Either the object is not visible in the wavelengths that you can detect or it is obscured. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[Saiph]

and you can see the pleides (an open star cluster) naked eye as well.<br /><br />With a decent aperture telescope, and a dark viewing site you can see a lot with the eye. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[MeteorWayne]

A number of nebula, clusters and one galaxy are visible naked eye, without a scope or binoculars. Of course with binocs there are more, and a scope many more. Of course, you need to be in darker skies than DC.<br />The Andromeda galaxy is easy to see under dark skies.<br />Clusters , easy are the Pleides and Hyades (both in Taurus), The Beehive (in Cancer), M33, the Double Cluster in Perseus. There are others.<br />The Orion nebula is also naked eye visible.<br />With a 4 inch scope there are dozens, with an 8 inch, hundreds, with a 12 inch, thousands. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[alokmohan]

One should have a star chart of course.Then you cant identify

 

[tfwthom]

Just one thing.......you will not see them in color. Your eyes can't detect the colors. That's why the photos are long exposure, so the film or CCD has a chance to pick up the color. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[MeteorWayne]

Excellent point! <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nexius]

Thanks everyone! Yea since im in the DC area I cant really see much but I try to get away some nights in the hills to check out stars with binocs. I dont think ive ever seen a nebulae with my binocs before. Now ill start to look for smudges since I know their not in color lol.. Soon I will be purchasing a telescope but im still researching them to find the one that will suit my area and wants. Thanks again, -Ben

 

[willpittenger]

That is ironic considering how superior in every other way the human eye is compared to film or any digital technology. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[MeteorWayne]

What cameras (of either kind) can do is collect the photons for an extended period of time. The numbers add up.<br />The eye is a real-time receiver, so it counts the photons at the <b> rate </b>they come in. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[nexius]

Yea. so that why when you leave your camera expose for an hr you can see the the nebula. Their is also something about false coloring to. I think the hubble takes pics that are not colored right? And then they use a program using rgb to make a false color?

 

[MeteorWayne]

Actually, the false colors are created when sensors sample wavelenths outside the visual range. For example if the ultraviolet is measured, and used to create a visual image they might use a violet or blue for that wavelength and shift the visual info down toward the red. Infrared also can be captured, and have red substituted for it. Then the normal visual part of the scene would be compressed on both ends. <br /><br />It's just a way to expand the information that can be expressed in the image, for after all, a picture is worth a thousand words <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[tfwthom]

From Steward Observatory:<br /><br />Once upon a time, the human eye was the only astronomical detector. In the late 19th century came photographic film... but even that has been replaced almost entirely by electronic detectors. <br /><br />Another point to consider is that "visible" light is only a fraction of the light emitted from astronomical objects. For these other regimes (gamma-ray, x-ray, UV, infrared, radio), other detectors are needed. In fact, the development of electronic "eyes" sensitive to other kinds of light is a research pursuit of many personnel at Steward Observatory! <br /><br />And even in visible light, the human eye is horribly inefficient and ill-suited for most research purposes. Scarcely 5% of the incident light gets "registered" in the brain, and the eye only accumulates light for about 0.1 second before the brain "reads" out the result. Plus, it is difficult to get quantitative information from an eyeballed measurement. Research astronomers typically use CCD cameras to act as sensitive electronic "eyes" that are near 100% efficient in collecting visible light, can collect light from an object for long periods of time and can send quantitative data directly to a computer for analysis and interpretation.<br /> <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[Mee_n_Mac]

<font color="yellow"><i>"That is ironic considering how superior in every other way the human eye is compared to film or any digital technology. "</i></font><br /><br />I'm not so sure it's the eye as much as it is all the signal processing that goes on behind the eye. I find it amusing when I think how much effort goes into translating information collected by various sensors into something visual so our eyes and brain can then be used to interpret the data. <div class="Discussion_UserSignature"> <p>-----------------------------------------------------</p><p><font color="#ff0000">Ask not what your Forum Software can do do on you,</font></p><p><font color="#ff0000">Ask it to, please for the love of all that's Holy, <strong>STOP</strong> !</font></p> </div>

 

[willpittenger]

That might be the normal case. However, if you take a normal photo and keep only a select color range, you might need to reassign the color values to see any remaining detail. I suspect that might have been done with Neptune and Uranus photos. Both planets show very little detail. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

By "human eye," I was talking about the eye and the portions of the nervous system responsable for sight.<br /><br />I should point out that I believe people have call the human eye (including the vision centers of the brain) the most advanced camera ever built. With technological cameras, you can't see stars with the same film used for daytime shots without long eposure times. The eye does this readily.<br /><br />By coincidence, I know the brain has been called the most advanced computer around. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[CalliArcale]

If anyone is mildly interested, the physiological reason you can't see colored nebulas with your naked eye is this:<br /><br />The human retina is covered with two kinds of cells: rods and cones. This website has a pretty good overview of the human eye. The rods are the most sensitive of all. They are capable of detecting a single photon! You have 120-130 million of them in each eye. They are most common in the outer regions of your retina, and entirely absent in the fovea (the focal point of your eye). These cells are remarkably sensitive and give you your night vision. However, they do not discriminate at all between wavelengths. They are most sensitive at a wavelength of 500 nm, but they basically only give you black-and-white vision. Dogs have a much higher proportion of these than we do, which is why they see so much better at night, but at the expense of color vision.<br /><br />The other kind of cell is called a cone, and you have about 6.5-7 million of them in each eye. Cones come in three flavors: one is most sensitive at 430-440 nm, another at 535-540 nm, and the last at 560-565 nm. These roughly correspond to blue, green, and red -- the three primary colors in additive color theory. (Combining all your cones, you see best at 550 nm, which is why green and red tend to seem so much brighter than blue.) This is *why* we perceive there to be three primary colors, in fact. Your brain interprets the output of these cells to extrapolate color information. The fovea of your retina is packed with nothing but cones. The drawback to cones is that they are not very sensitive in dim light. Thus, the price we pay for our exceptional color vision (among the very best in the animal kingdom) is that we have relatively modest night vision.<br /><br />So what does this mean? It means that as things get dimmer, your cones are less stimulated. Faint objects, such as the Orion Nebula, are so dim the <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[nexius]

Thanks Calli ! Very interesting indeed

 

[yevaud]

<i>This is why amateur astronomers learn to look at really faint objects out of the corner of their eyes. Your peripheral vision is far more sensitive to faint light.</i><br /><br />True. We were trained to locate faint objects using what's known as "averted glance," e.g., espying it out of the corner of your eye. Very useful in locating faint objects when the sun is just going down. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>