Evening star., 1926-06-13

Right: Col. Umbert Mobile, designer
of the Norge, with his mascot "Ti-
tinia," standing i'm front of the frame.
work of the giant airship at Teller.
tPhoto: copyright, & is26 o by er,, New York
time are in the clouds-which give no
| chance at all for even the finding OF
! approximate speed-you do not know
whether you have moved 100 or 200
| miles between the observations. In
| the polar basin you have in the Sum
/ mer only the sun for your observa-
| ton, as the periods when the moon
also can be used are very short. These
did not coincide with the time for our
| flight and the best thing was to base
our navigation only on a single obser-
vation, not trying to combine two of
! them.
What you want to know is your
| latitude and longitude. If you take
| your observations at noon and mid
night time, when the sun is due south
| or north, you get position line run
! ming east and west that gives your
| latitude. If at the same time a bear
| ing of the sun shows it to be due
south or north. according to the sun
| compass and the magnetic compasses,
and whether you stand east or west
| Of the supposed line.
On the other hand if you take OBJ
servations of the sun when it is due
east or west--that is, clocked am. or
! pm.-you get a position line running
south and north, giving you your
longitude.
Apart from these methods we OBJ
! tained our longitude at intervals dur
| ing the flight to the Pole by radio
! bearings from the Kings Bay wire'
| less station, on the meridian of which
we naVigated.
Magnetic Pole Well Behaved.
Finally, we want to draw attention
/ to a misunderstanding among laymen,
namely. that the magnetic compasseS
are completely out of action at the
Pole. That would be the case If the
| magnetic pole were lying upon the
| geographic pole. But fortunately for
| navigation this is not the case. The
! magnetic pole is down on the Boothia
! Peninsula on the north coast of Can
| ada. Thus there is certain magnetic
| force at the geograp phical pole, al
though it is weak.
| Going from SDitZbergen to the Pole
there is no great change in the devi-
ation-that is, there is no great diff
| ference between the magnetic north
| and true north. At the Pole itself
! the deviation can be said to be only
between zero and 260, as everything
| is true south at midday
If YOU change your deviation you
must change it so and so many de-
grees. corresponding to the angle be-
tween the medidian on which you ar
rived at the Pole and the meridian on
which you will proceed.
Going toward Point Barrow diff
culties arise if you must navigate by
magnetic compasses alone. because the
deviation changes so rapidly. Between
80 north and 80 it changes 80 degrees,
that is, to 10 degrees every hour. III
YOUR position is wrong YOU use dew.
alton with quite a big error attached
TO it. and this gives you presently a
still bigger error in position. On that
part of the distance we could not pe
too careful.
An Interesting job.
AS the ship passed out OF Kings bay
the navigator set to work on the most
interesting lob navigator ever mad
the crossing of the north polar basin
from Spitzbergen via the Pole TO
Alaska. With clear weather ana sun
naratively easy. but should much fog
occ,,r he WOULD be up against quite a
problem.
We ought to mention that according
tn orr routine the navigator was the
sovereign mower respecting the Whole
question of bringing the snip TO ltS
destination, unless special meteoroiog'
ical conditions should make a capital
change necessary. Such a question
would eventually be decided by our
second in command, who also was the
navigator and the captain OF the snip
Fortunately. this question never
arose. -
As has been explained, the ship
north from Spitzbergen was maneu'
yered into the meridian of the Kings
Ray wireless station after the COM
passes had been checked through
bearings.
Checking Speed and Drift.
Approaching the ice the wind, in
our low altitude, slowed our speed to
40 miles an hour. Toward 11:56 AIM
all time given in Greenwich mean Tune
the drift increases to the port. Ihe
altitude was increased from 600 feet
to 900. where we found Ia degrees
rift to the same side and an increased
.5peed and drift observations were
taken constantly. If the sun COM
pass mounted to more than 4 degrees
the setting of this was altered. For
smaller angles the rudderman was
only ordered to keep the picture or
the sun a corresponding number or
degrees out to the side OF the center
of the glass plate, the field of this be-
ing degrees to either side of the
center
At 1:10 pm. we got wireless bear
ing showing that We stood 3 nautl-
cal miles to the east of our meridian.
Steering up against the easterly wind
| was slackened degrees. so that we
gradually should get back again.
Back on the Meridian.
At 1921 pm. we got longitude OBJ
servation of the sun which said that
we were back on our meridian again.
Our latitude was then such that we
could use a very simple method for
the calculat tion of the observations
of the sun north of S5. There is so
little difference between the azimuth
fand hour angle that all observations
can be calculated as midday and
midnight observations. That is, the
time must be taken and the position
line drawn perpendicular on the sun
meridian at a distance from the Pole
equal to the difference between the
height of the sun and its declination
at the moment.
With the sun close to east or west
there will be some small errors down
to IS, but it is easy to see which
way 1t will work and take it into
consideration. Further wireless