Mars, a Not-Always-Red planet

Status
Not open for further replies.
M

marjcudal

Guest
<p>I have read an article regarding the true color of planets such as Mars. The author said that the martian rovers used filters which are not really designed for the "true color" picture. The filters on the rovers do not correspond to the color sensitivity of the human eye. Some of the filters only let through infra-red light, which is invisible to our eyes. He also added that the reason why colors in the images are a bit weird at times. Sometimes, the infrared filters are used. Other times, the way the three-color image was constructed may be too heavy in the red, or the blue, distorting the colors. Worse, as lighting changes, so do the colors! When the Sun is high, the colors look different than when it is low. The amount of dust in the air ruins the color balance as well. Even worse, dust scatters light. The sky near the Sun looks bluer in images from Mars because the dust in the air "forward-scatters" blue light; in other words it takes blue light from the Sun and focuses it more toward the camera. The sky near the Sun looks bluer, and farther away it looks redder. Light reflecting off the rocks can also suffer from all sorts of color imbalances too.</p><p>&nbsp;</p><p>Is this true? Are there any proof or pictures that would prove that Mars is not-always-red? </p>
 
M

MeteorWayne

Guest
<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I have read an article regarding the true color of planets such as Mars. The author said that the martian rovers used filters which are not really designed for the "true color" picture. The filters on the rovers do not correspond to the color sensitivity of the human eye. Some of the filters only let through infra-red light, which is invisible to our eyes. He also added that the reason why colors in the images are a bit weird at times. Sometimes, the infrared filters are used. Other times, the way the three-color image was constructed may be too heavy in the red, or the blue, distorting the colors. Worse, as lighting changes, so do the colors! When the Sun is high, the colors look different than when it is low. The amount of dust in the air ruins the color balance as well. Even worse, dust scatters light. The sky near the Sun looks bluer in images from Mars because the dust in the air "forward-scatters" blue light; in other words it takes blue light from the Sun and focuses it more toward the camera. The sky near the Sun looks bluer, and farther away it looks redder. Light reflecting off the rocks can also suffer from all sorts of color imbalances too.&nbsp;Is this true? Are there any proof or pictures that would prove that Mars is not-always-red? <br />Posted by marjcudal</DIV></p><p>Basically there is some truth in there. The filters do not correspond exactly to the human eye, so some effort must be expended to come close to what the huma eye would see. In general they are able to come pretty close, since the newer landers and rovers have targets of known color that are imaged by the same cameras and filters. They will never be exact, though.</p><p>In general the red color is correct, as you can see if you look at it from here on earth. The reddish hue of Mars can easily be seen.</p><p>I've never hear of the "forward scatter" effect before, so can't really comment on that.</p> <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>
 
M

MeteorWayne

Guest
<p>Welcome to SPace.com.</p><p>Just to let you know, it is against the rules to start&nbsp;3 identical threads in three different fora. It's considered spamming.</p><p>So next time, just pick the best place to start the thread and post your question.</p><p>But feel free to ask lots of questions!</p><p>Wayne</p> <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>
 
Status
Not open for further replies.

Latest posts