|Lowell's Canals: Demarcations
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
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?
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 appeared.
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,
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 Lick.
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 for canals."
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
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
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 darkening.
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 were unknown.
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
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
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 cratered areas.
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
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.