Demarcations in Discernment
by Duane Dunkerson
The markings on Mars are roughly constant but do change
from year to year. There is, as E.C. Slipher termed it, an
additional "secular" amount of change that is more local
in time and region. At its closest approach to Earth, Mars
is 26 arcseconds in diameter and has the Southern
Hemisphere turned towards the Earth. As one telescopically
observes Mars, the interrelationship of Mars' rotation and
Earth's rotation results in surface features noticeably
shifting as a whole after 4 days. After 40 days, they are
back where they started. Exact reproduction of the
position of surface features occurs once every 15 years.
At favorable and unfavorable positions of Mars relative
to Earth, at times of the year very varied, and with
diverse instrumentation and observers, there appeared a
class of features that DeVaucouleurs declared to be an
irritating enigma. He was referring to the canals of Mars.
They partake of a notion that there could have been
Martians, godlike, in old realms of imagination furthering
the mythic fantastic possibilities of comparatively
superior, and better, civilizations than our own.
The basis for the belief in these Martians lies with the
canals. They, in turn, are dependent on drawings made by
astronomers from another era. Beer and Madler in 1830-1832
drew Mars as having wispy lines. They were using a 3
3/4-inch refractor. Proctor drew Mars as having thick
channels. Dawes in 1864-1865, at a time when Mars was
favorably placed for Earthly viewing, also drew wisps, and
streaks for some markings of Mars. Nathaniel Green, using
a 13-inch reflector, and Webb also drew Mars somewhat
similar to Proctor.
As late as 1961, E.C. Slipher stated flatly that the
Martian canals existed. According to Slipher, all skilled
observers who go to the best available sites with the best
available telescopes did not fail to see the canals. He
called them the wonderful network of canals. This is a key
point, noted many years earlier, that a few canals, wisps
or streaks, however ill-defined or in the reverse, are
nothing more than a curiosity of planetary observation;
but to put these interrelated canals into a network - then
you had a fixation, a realization that these canals, by
being connected, represented activity. The canals were
made. A network meant design. By whom? For what?
In some respects, the Martians, who built the canals,
were in our image in that the canals provided pathways for
the flowing of fluid, presumably water, to regions of Mars
having need of an augmented water supply. They were for
irrigation to Martian regions drier than the Martians had
wanted them to be.
E.C. Slipher, in 1961, showed photographs of the canals.
Unfortunately, he said, the original photographic plates
showed the canals as well as could be seen visually but
these photos did not reproduce well for publication.
Approximately 50 years before, Percival Lowell had also
said his photographs of Mars showed the canals but the
tiny images of Mars containing these canals did not show
up well in the popular magazines in which they then
As is well known, Lowell was the ardent champion of the
existence of the canals of Mars, the Martians, their
network of waterways, and their technological and other
superiority to us. Even so, he did not discover these
wondrous canals. Lowell took his cue for the existence of
the canals from Schiaparelli. It was Secchi in 1869 who
drew channels (canali) on Mars. In 1877 Schiaparelli drew
what others had seen as much narrower and linear. They
would become stark stalks. In 1877 he was using an 8
1/4-inch refractor. He would later use a larger telescope.
He said he glimpsed a vast, intricate network of fine
lines criss-crossing Mars. He drew them despite their form
often being vague. Sometimes he saw them as clear and
concise. Either as clear or vague, for him they were not
broad channels but finer and, above all, systematic and
not varying in their arrangement. Not varying, that is,
until 1879 when, during the Martian spring he began to see
doubles. Where once there had been one lonely canal
traversing hundreds or thousands of miles, there was now a
partner, matching mile for mile the original one and with
a constant spacing from that original. It became not a few
doubles here and there but many of them.
Prior to 1879, Schiaparelli's map from 1877 showed not
anything that can be truly designated a canal. There were
no numerous lines or fine stripes he later found in such
abundance. Then any less than prominent Martian markings
appearing as a streak became a canal. Early on, the canals
usually showed themselves only one or two at a time. These
showings were only in glimpses, a snatch of clarity only
very briefly and not very often in long observing
sessions. He found the canals on a fine clear night in
Italy. It was the first time he had used that telescope.
Lowell, in 1894 in Arizona, at first doubted he was
seeing the canals with his 18-inch refractor. As he gained
experience in sighting them in very brief periods of good
seeing, he saw more and more canals. He would see new
canals, canals never before seen and go on to outdo
Schiaparelli. Lowell was seeing the canals also during his
first use of his telescope. This was during the favorable
opposition that commenced October 13, 1894. He was present
in an opening in the woods on a low mesa, close to the
west side of a town of 800, Flagstaff. With his keen
eyesight and the realization that a whole new instrument,
the air, the good air, could be put into use for planetary
observation, Lowell and his associates saw 183 canals
during that 1894-95 opposition. The Martian April came in
our June. Martian August was our November. The Red
Planet's vernal equinox was April 7, 1894. The summer
solstice came August 31. One degree on the Martian surface
was 37 miles. Through the degrees from the poles to the
equatorial regions, Lowell saw, as others before him had
seen, the seasonal darkening of features. Some markings
would always get darker in the Martian spring and fade in
the Martian autumn. The canals participated in this wave
of darkening, the dark advancing from pole to equator.
A tumult in astronomy had also advanced. It went into the
beginning of the 20th century and peaked in 1907. The
tumult was the Mars furor. Lowell was at the center of it.
Others had decreed there were no canals on Mars. No
Martians were there as canal builders. No water was at the
poles to be brought to the equatorial regions by those
spindly-looking canals. Lowell said otherwise - canals,
Martians, and their civilization all in one breathtaking
sweep of assertion. For him astronomy was an interest and
a mood. He exuded Darwinism, pragmatism, romanticism, and
an imagination, Baconian, as method.
He could discern canals on Mars. Barnard, with a 36-inch
refractor, saw much detail, but found no canals. Charles
Burton in 1869 using the Rosse reflector noted the most
remarkable of many details were black very small points
distributed abundantly in one region of Mars. No canals.
Hale in 1909 using the 60-inch Mt. Wilson telescope
stopped down to 44 inches saw much bewildering intricate
detail but no canals. Gaston Millochau, in 1899-1903,
using the great Meudon refractor of 32 3/4 inches, saw
much irregular detail on the surface of Mars. No canals.
Cerulli in 1897 with a 15 1/2-inch refractor found some
well known canals, like Lethes, when viewed under perfect
seeing conditions, lost the status of a line and became a
complex system of very small spots. Antoniadi had superb
seeing for the Meudon refractor on his first night. He
observed Mars then. There was too much detail to be drawn.
No canals. In 1924,at the best opposition of the 20th
century, observers at Flagstaff, upholding the Lowellian
tradition, saw the canals. Trumpler, also in 1924, using
the Lick 36-inch refractor drew a great many canals.
Charles Young with a 23-inch refractor never saw the
canals as Schiaparelli had drawn them, nor did Keeler at
Antoniadi sent drawings of Mars to Lowell. Antoniadi had
used the Meudon refractor. Lowell thought the best one
(which showed canals) as the one Antoniadi had marked as
being done when the air only permitted tremulous
definition. In those drawings during much much better
seeing the canals were not to be found. E.B. Frost was
asked if the mighty Yerkes (40 inches) refractor could
reveal the canals. Frost - "Yerkes telescope too powerful
Frost was right. Lowell had argued that telescopes of
smaller aperture were best for sighting the canals. Not
too small of course but at least Lowell's 18-inch
refractor served the purpose. Schiaparelli started his
observations of the canals with an 8 3/4-inch refractor.
Schiaparelli seems to be a special case. All other
consistent reputable reports of canals involved larger
apertures. Going well beyond Lowell's 18-inch up to 60
inches in aperture did not help to discern the canals.
Optically speaking, bigger is better when the atmosphere
allows for it. Lowell, after the 1894-95 opposition used a
24-inch refractor but he usually reduced the effective
aperture to 18 inches or less with a diaphragm.
So the canals have a correlation to aperture. Also, with
the larger apertures, where those canals were to be seen
would have spots, splotches, and dots taking up that
space. Only in poor seeing, according to Antoniadi, could
he, and by implication, could others, see the canals.
Antoniadi also, among others, noted that the canals lacked
perspective. They went across the globe of Mars for great
lengths and should have assumed the character of great
arcs of circles. They did not. This could be because what
the observers discerned as giving opportunity for the
canals were not on the surface of Mars.
Cerulli from July 1896 to February 1897 saw some canals
easily in July when Mars was 7 arcseconds. Later, in
December, when Mars was 17 arcseconds, the same canals
were the same size. Schiaparelli did it in the reverse on
an occasion. For him, when Mars was 21 arcseconds he saw
no canals but one in a region of Mars. Later, after the
angular size of Mars had gone to 5.7 arcseconds, he then
saw canals in that region. Both these cases can be perhaps
explained by having that which lends itself to canal
formation as being quite small.
This minute facilitator would also need to participate in
the wave of darkening that comes with the Martian spring.
The canals have always been a part of the wave of
darkening. McLaughlin in 1954 thought that albedo changes,
as he termed it, could result from wind action with
volcanism to supply dust deposits. Sagan thought that
wind-blown dust could be the cause of the wave of
The Martian wind on a global scale is estimated, on
average, to have a velocity at night on flat terrain of 2
meters (m)/second (s). At noon on the flats it is 6 to 8
m/s. Near mountains the velocity can be as much as 20 m/s.
Certain storms to which Mars is subject, can produce wind
velocities of 50 m/s. The polar areas can endure a
velocity around 100 m/s.
Dust can rise to 40 km above the Martian surface. Large
dune fields exist on Mars. One dune in particular is
reputed to be largest in the Solar System. The planet is
nearly always seen through a dusty veil. Martian dust
plumes are huge. They can be 20 km long and 1 km high.
There are local, regional, and global dust storms. Lowell
thought the Martian atmosphere was placid. He observed in
an era when the vast dust storms to which Mars is subject
Another outstanding class of features of Mars is its
craters. There are more craters in the Southern Hemisphere
than in the Northern Hemisphere. Most observers have found
more canals in the Southern Hemisphere. The Viking and
Mariner spacecraft revealed about 170 large Martian
craters, mostly greater than 62 miles in diameter, and
6,000 smaller craters.
Could one see the craters, any craters, from Earthbound
telescopes? If one has perfect seeing, a rather rare
commodity, a fairly accepted measure of resolving power of
a telescope is Dawes Limit or 4.56 arcseconds divided by
the aperture in inches. This is a relationship that was
derived empirically by Dawes in finding what aperture
among smaller refractors could separate double stars.
Experienced planetary observers know that this limit does
not strongly pertain to extended objects such as planets
as opposed to point sources like stars. The experienced
argue that the limit for planetary viewing can be bettered
by 2 to 14 times more acutely. Beyond these matters of
opinion, it has been found that the Hubble Space Telescope
(HST) is capable of revealing craters on Mars. The HST has
an aperture of 94.5 inches, its planetary camera at f/30
has an angular resolution of 0.043 arcseconds. The HST has
no dense earthly atmosphere to hinder its work and can get
close to theoretical limits for resolution. If one accepts
Dawes Limit, then the HST should be able to see objects on
Mars with a diameter of about 8.1 miles at a favorable
opposition of Mars. During 2001 the HST had a look at Mars
on one occasion. More than a few craters could be
recognized in the image it secured.
But then Lowell and the rest had nothing like the HST
available to them. Did they ever see craters on Mars? The
consensus is that they did not. Given that, could Lowell
have been aware of craters on Mars? I believe there is a
possibility that he may have done so. I propose that the
canals of Mars are a function, like a mathematical
function but not as precise, of the presence of Martian
dust aloft over craters on Mars. The existence of the
canals has always been found at the very limits of
visibility. One needs the best eye, the best sky, and the
best telescope. One more factor is required and that is
the ability to discern the canals. I don't believe one can
say the ability to "see", no, more to discern. To realize
the craters, to put them into existence, Lowell could have
seen Martian dust framed against a backdrop of craters. It
was somewhat like the Rorschach tests where patterns can
be found and usually those patterns are rather routine
except among the more imaginative persons.
Once one canal or two became fixed, then the orientation
of the remaining community of connecting canals then
became determined. If not, one had a mass of perceptions
unorganized and "wasted" (if the observer was so disposed
to regard the fleeting imagery) and so to "make use" of
the discernment then the rest of the canals could not
assume independent orientation. A network sprang up. Once
known, then in the future any part of the canalic artwork
reestablished itself and the rest followed as seen before.
If the background crater was too large or the aperture of
the telescope was too large, then the dust had nothing for
orientation supplied by the observer, to "direct" it, to
"frame" it, as it were. The canal would not form; it would
smear out into spots or splotches. If the crater or
aperture were too small, then not sufficient supportive
function would be present. Only an intermediate range of
size of craters and telescope would serve the purpose. How
many craters would be needed per canal? I presume this
could vary. Certainly the anchors of the network would
have many craters determining the canal. But in other
instances it might take only two points, a start and a
finish, two craters to determine a line, a canal. Lowell
may have not used the same craters as an aid in discerning
certain canals. The dust might have been over other
closely adjacent craters. His plates showing the canals as
they appear in his book, Mars, are for the 1894-95
observations. They are yet more like streaks and more
indistinct than they would later become. Further
association by him with his creation made for him, as for
Schiaparelli, more definitive characterization of what
they thought should be seen.
There was a boundary between the seen and the discerned.
Most crossed the boundary willy-nilly and at will found
what could only be discerned as that which they had seen.
Maunder had seen sunspots much smaller than a single
sunspot if the sunspots made for a linear composition or
nearly so. A somewhat similar formation of canals could
have taken place. Nevertheless, the canals were not a mere
summing up of roughly aligned features too small to be
individually distinguished. The craters were never seen.
Lowell misspoke when he said the saw canals, at best, he
discerned them. In sparsely cratered areas, he could have
used fewer craters to have the line for the canal. It is
possible that features other than craters could have
contributed to the existence of the canal. Even so, the
craters are the prevalent surface features that could have
aided in canal discernment. Other features are too few as
a class of object and, on the whole, too often dispersed.
In any event, the canals could traverse sparsely populated
Here and there Lowell saw an oasis on Mars. This was a
place where more than one canal seemed to run into a
junction. It could have been that an oasis was not from
whence a canal originated but rather was where canals met.
Given some differing starting angles for the canals, some
would intersect and the underlying topography could, at
places, favor apparent termini. The canals did not issue
from the oasis; however, it is rather that they met there.
As for the famous or infamous double canals, I propose
that those doubled canals were there when additional dust
was in the area of a suitably sized group of craters.
Should there be more dust, but in the area of too large a
crater or too small a crater, no double. Those craters
that could support doubles had to be of a certain size
range. If all the necessary craters could be classed in
the nearly same size range, then a double, the secondary,
would parallel the original, the primary, canal for the
duration of the course of the primary. Again, if one
crater at the start of a canal and one at the finish were
large enough in the presence of increased dust, a double
could be realized. The sizes for the defining craters
would determine the spacing of the doubles apart from each
other. New canals, double or not, could pop up when
sufficient dust for sufficient duration newly entered an
area seen previously by Lowell.
Have I too raised sufficient dust for a suitable duration
and built up a network of reasoning ever as much lacking
in reality as Lowell? There are ways to test the
reasoning. In 2003 Mars will present a very favorable
opposition. Lowell's telescope still stands in Flagstaff.
Also, at any desired remove from Flagstaff could be
constructed a representation of the cratered Martian
surface, properly illuminated, and with dust before one's
eyes. Perhaps one could drop red or at least dark food
coloring into an aquarium, in front of "Mars" and look
through the watery atmosphere for canals to form. More
elaborate and more realistic conditions could be generated
for such in-lab tests. As for a luney idea, one could try
to find lunar canals. Long ago Beer and Madler found
streaks on the Moon that upon closer examination were
actually strings of little craters. One need not be
restricted to recreating their finding. Certainly there
are enough craters on the moon. The dust is another
matter. One might hunt for lunar canals by, perversely,
observing the Moon on cloudy nights. The brightness of the
Moon may necessitate daytime viewing or employing color
filters or a polarizer. Probably the best optical
instruments for use with the Moon in this regard would be
binoculars or spyglasses.
However one goes about finding Martian or other canals
now at this late date, one must remember an important
other requirement. One must be able to "see" them. One
must be receptive to an awareness of their existence.
Beware, these canals partake of gods, demons, and fabulous
creatures. You are entering a zone at the limits of
visibility where the psychological, religious, and
philosophical can storm upon you at full gallop. Hold
tight to your preconceptions, modify them much by hope and
little by fear. Alone, one night, soon, if you dare, with
the God of War, the Red Planet mysteriously comes into
your ken. Have faith, Mars and its canals still exist.
Look for them especially after storms on Mars. Some
artistry is required. The marvelous excitement of another
form of highly developed life is still there. They are
intelligent and smarter, super though not superhuman.
Grasp an eyepiece, put it in your wayback machine and
become a traveler in time to a great era in human time. To
a time when science still had much humanity. Fanciful it
was, rich in ideas, ripe with possibilities, positively
glowing with them. An awesome potential then in more
respectable and more courteous surroundings. So many then
could be so much in contact in that society's
consciousness, talked of, thought about, very close to
real. As close as it gets without getting there. Straining
the scientific resources to confirm the craftsmanship of
the astronomical instruments of the day. Blend in
scientific imagination of the planetary observers and know
the new, wondrous personal view tempered by societal
strictures there in the dark backyard, the basement lab,
or in the reading room.
You will never see the craters, they are beyond seeing;
but they can be briefly known indirectly. Lower the Dawes
Limit. Survey areas of Mars such as the Vastitas Borealis,
Elysium Mons, Hesperia Planum, Terra Cimmeria, Valles
Marineris, and the Amazonis Planitia. These certainly are
real. Spacecraft in orbit about Mars have shown them quite
well. But ultimately you are not going for objectivity
here. You and Mars. The canals. Have at it.