Mars Global Surveyor Images - July 24-30, 2003

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?

Regards
Paul Blake

Paul Blake wrote:

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?


This is because you are looking at them in a room where the light is
arriving from above the monitor, and these pictures are illuminated
from below, left. Turn your monitor upside down (so that the bright
half of the crater wall is farthest from your light source), and all
will be well.

--
John Popelish

Paul Blake wrote:

"Ron Baalke" wrote in message
...


MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html



To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?

Regards
Paul Blake






David Ford: The lighting does not appear to come from the lower left,
at all (as the accompanying text states), but from the upper right; and
they do look a bit domish. However, the interesting feature is the way
the two 'craters' in the lower left meet together ... ? ... if they are
craters, they have filled with dust and possible aolian deflation
followed; if they are domes, they appear to have collapsed back into
themselves ... but if that were so, then what is the nature of the
layering ... doming and then deflating of flat laying sediments perhaps ...?

David Ford wrote:

David Ford: The lighting does not appear to come from the lower left,
at all (as the accompanying text states), but from the upper right; and
they do look a bit domish.
[snip]

You're putting the cart before the horse. If the lighting were indeed
from the upper right the landforms would have to be convex, but since
the lighting is in fact from the lower left the shapes are concave,
i.e. craters. There are various tricks for "inverting" a scene, but
it's hard to predict what will work for a given individual. Turning
your monitor upside-down, as John suggested, might be a little
awkward, but if you print the picture and look at it from different
angles the concavity may appear. Sometimes defocusing or averting
one's gaze can provoke inversion; looking closely at a small feature
may also help. Even blinking can make an ambiguous scene seem to invert.

The Dutch artist M.C. Escher made use of illusions based on inversion
in some of his prints, notably "Concave & Convex", 1955.

See http://www.worldofescher.com/gallery/A9L.html.

--
Odysseus

John Popelish wrote:

Paul Blake wrote:

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?

This is because you are looking at them in a room where the light is
arriving from above the monitor, and these pictures are illuminated
from below, left. Turn your monitor upside down (so that the bright
half of the crater wall is farthest from your light source), and all
will be well.

Do we know for sure that the light is coming from the lower left?

I think part of the problem is that the main features are lit on the
upper right side but the interior features are lit on the lower left,
making it look to me like flat hills with concavities on top. Also, the
"crater" on the upper right side of the picture has a shadow just above
and to the right of it which looks odd if the light really is coming
from the lower left.

--
Joe of Castle Jefferson
http://www.mindspring.com/~jjstrshp
Site Updated November 25th, 2001

"Defend the cause of the weak and fatherless; maintain the rights of the
poor and oppressed. Rescue the weak and needy; deliver them from the
hand of the wicked." - Psalm 82:3-4

John Popelish wrote:

Joe Jefferson wrote:

John Popelish wrote:

Paul Blake wrote:

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?

This is because you are looking at them in a room where the light is
arriving from above the monitor, and these pictures are illuminated
from below, left. Turn your monitor upside down (so that the bright
half of the crater wall is farthest from your light source), and all
will be well.

Do we know for sure that the light is coming from the lower left?

I think part of the problem is that the main features are lit on the
upper right side but the interior features are lit on the lower left,
making it look to me like flat hills with concavities on top. Also, the
"crater" on the upper right side of the picture has a shadow just above
and to the right of it which looks odd if the light really is coming
from the lower left.

The caption reads, "This picture is illuminated from the lower left."

D'oh! I guess I should have scrolled down the page.

--
Joe of Castle Jefferson
http://www.mindspring.com/~jjstrshp
Site Updated November 25th, 2001

"Defend the cause of the weak and fatherless; maintain the rights of the
poor and oppressed. Rescue the weak and needy; deliver them from the
hand of the wicked." - Psalm 82:3-4

Joe Jefferson wrote:

Joe Jefferson wrote:

John Popelish wrote:

Paul Blake wrote:

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the brain
refuses to accept that they are craters. Do other people have the same
problem?

This is because you are looking at them in a room where the light is
arriving from above the monitor, and these pictures are illuminated
from below, left. Turn your monitor upside down (so that the bright
half of the crater wall is farthest from your light source), and all
will be well.

I think part of the problem is that the main features are lit on the
upper right side but the interior features are lit on the lower left,
making it look to me like flat hills with concavities on top. Also, the
"crater" on the upper right side of the picture has a shadow just above
and to the right of it which looks odd if the light really is coming
from the lower left.

To follow up, I used Photoshop to invert the levels (essentially turning
it into a negative image) and voila! They now look like well-defined
craters with terraced hills inside them. Even the little one just to the
left of center now looks like a crater instead of a grounded UFO (Sorry,
Mr. Hoagland).

How does your variation compare to just rotating the image 180
degrees, so that the more natural (to humans looking at pictures)
lighting angle occurs?

--
John Popelish

"Joe Jefferson" wrote in message
...
John Popelish wrote:

Paul Blake wrote:

"Ron Baalke" wrote in message
...
MARS GLOBAL SURVEYOR IMAGES
July 24-30, 2003

The following new images taken by the Mars Orbiter Camera (MOC) on
the Mars Global Surveyor spacecraft are now available:

o Layers in Crater Cluster (Released 24 July 2003)
http://www.msss.com/mars_images/moc/.../24/index.html

To me these craters look like domes. I keep looking at them but the
brain
refuses to accept that they are craters. Do other people have the
same
problem?

This is because you are looking at them in a room where the light is
arriving from above the monitor, and these pictures are illuminated
from below, left. Turn your monitor upside down (so that the bright
half of the crater wall is farthest from your light source), and all
will be well.

Do we know for sure that the light is coming from the lower left?

Yes.
It is.