Improvements in Instruments for Noting a Ship's Position at Sea from Observations of Astronomical Bodies.
Year: 1894

page_text: Date of Application, 5th June, 1894-Accepted, 5th Nov., 1894
COMPLETE SPECIFICATION.
:
Improvements in Instruments for Noting a Ship's Position at Sea
from Observations of Astronomical Bodies.
I, WILLIAM HENRY BEEHLER, of 1801 Q Street, N.W. Washington, D.C.
United States of America, a Lieutenant in the United States Navy, and serving as
Chief of the Division of Marine Meteorology in the Hydrographic Office of the
Department of the Navy do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :—
My invention relates to improvements in instruments for taking observations of
heavenly bodies and solving mechanically the parts of the astronomical triangle
used in navigation, surveying, and other like work, and it is especially intended
to facilitate the computation of such elements as are necessary to determine
position and compass error of a ship at sea independent of the visibility of the sea
horizon.
My present invention is especially intended to provide for certain improvements
upon and changes in the instrument known as or termed by me-a "Solaro-
meter"
primarily intended to take observations of the sun, but equally suited for
observations of the other heavenly bodies.
Reference is had to the accompanying drawings, in which the same parts are
indicated by the same letters throughout the several views.
Fig. 1 represents a side elevation of the upper part of the instrument as
mounted aboard ship, the plane of the cardboard indicating the fore and aft line
of the ship.
'
Fig. 2 represents a view of the upper portion of the instrument as seen from
the left of Fig. 1, the lower part of the said Fig. 2 being shewn in central vertical
section.
Fig. 3 represents a central vertical section of the lower part of the instrument
and the pedestal on which it is mounted, the section being in the fore and aft plane
of the ship.
Fig. 4 represents a section along the line of Fig. 2 and looking down.
Fig. 5 represents a central vertical section through the axis of the telescope and
of the object tube.
Fig. 6 represents an enlarged view of the interior of the telescope tube showing
the cross-hairs as they appear to the observer, and
Fig. 7 represents a detail view of the attachments by which the telescope box is
held on and allowed to move along the declination circle.
A represents the pedestal which may be of any desired pattern, and is bolted to
the deck by means of bolts through the flanges a. The upper portion of this
pedestal is made bowl-shaped as at A' and provided with an upper flange or
stiffening rib a', on which the various parts of the instrument are supported.
The bottom of this bowl-shaped portion A' is preferably provided with an
aperture a² to allow the escape of any water or other liquid or solid particles that
might fall into the top of the pedestal.
A ring B is suspended on gimbals on the top of this pedestal, and at right-
angles to these gimbals are the gimbals c by means of which the bowl Čis
suspended in the ring B.
This bowl C is provided with a heavy downward projection C¹ whose weight
lowers the centre of gravity of the apparatus and assists in keeping the said bowl
steady on its gimbals regardless of the motion of the ship.

page_text: This bowl is preferably lined with porcelain cl so as to lessen the friction of the
mercury on the inner surface of the said bowl. This porcelain lining would enable
metals that amalgamate with mercury to be used in the manufacture of the bowl C,
though I preferably use cast-iron for this purpose. The bowl C has a cover C⁹.
The inner gland C³ is perforated as at c to allow the coluinn Q plenty of lateral
play but this gland may be removed if desired.
At the upper edges of the bowl C and 180° apart, two pointers C* and C³.are.
provided, which are pivoted at c and are held in any desired position by the
springs. These pointers may be arranged in any known position relative to the
ship, but to avoid index corrections, are preferably arranged in the bow and stern
line of the ship, and are adapted_to_swing down over the azimuth circle H, and to
indicate the bearing that the bow and stern line of the ship makes with the true
bearing of the sun or other body observed, which bearing compared with the
compass bearing of the ship's head as indicated by the lubber point in the ship's
compass, will give the compass error as will be more fully hereinafter described.
The outer bowl C, is partly filled with mercury G in which mercury an inner
bowl F is floated.
This inner bowl is perforated at its bottom to receive the lower ball K¹ of a ball
and socket joint, whose upper ball K is secured to the lower ball by means of the
screw-threaded tongue k'.
Over the base of this ball K', and securing the same revolubly in position, a
cap F1 is attached by bolts f¹ to the base of the bowl F. This cap is provided
with an annular groove above the sharp edges f2, and the function of these edges
and of this groove are to catch in the mercury, and to lessen vibrations of the
bowl F, or to accomplish the same result as a bilge keel in a ship.
Floating in this bowl F is a float N, which is buoyed up in the mercury G in
the said bowl F, and is prevented from moving too far to either side of the bowl F
by means of the ball and socket joint already referred to. This float is similar in
interior contour to the interior contour of the bowl F, except that it is provided
with annular grooves above the sharp edges n and n¹, which edges serve to lessen
the vibrations of the float in the mercury, as has been already described with
reference to the edges 2 on the outer base of the bow! F. In the interior of this
bowl N and low down therein a mass of lead N' is provided, the purpose of this
mass of lead being to lower the centre of gravity, and produce stable flotation in
the mercury.
Enough mercury is put into the bowl F to float the float N, with the weight of
the instrument and connected parts mounted thereon, and at the same time not to
immerse the float so much as to cause excessive friction on the ball K which is
revolubly connected to the base of the float..
It will thus be seen that the float is perfectly free to move through small
distances laterally in the bowl F, or to revolve freely about its vertical axis.
All the various surfaces of the float and the bowls in contact with the mercury
may be lined or coated with porcelain, shellac, or varnish to lessen friction.
Rigidly secured in the vertical axis of this float is the column Q, connected by
means of the shoe piece Q to the bottom of the float, and passing up through the
lead which is preferably poured around it in the melted condition, and thus assists
to hold the same firmly in position. The weights in, or attached to, this float N
should be so adjusted that the axis of the said column Q is at all times
carried absolutely vertical, and normal to the plane of the mercury in the inner
bowl F.
This column Q is made hollow in its upper portion to receive the rod Q
(Fig. 2) which is clamped to the said column by means of the set screw q. Above
this column Q a sleeve Q is secured fast to the rod Q' by means of the set screw q',
and on this sleeve the horizontal circle or azimuth circle H is rigidly attached, (as
by the set screw q'), and the various other parts of the instrument above the
azimuth circle are revolubly mounted.
Q* represents an outer sleeve revolubly mounted on the sleeve Q³, and carrying

page_text: the vertical frame R which consists of two quadrantal brackets connected together
by ribs r, and terminating in bosses to receive the screws R¹ on which the semi-
circular telescope carrier bracket R is pivotally mounted. This bracket R³
is made of two side plates 2 secured together with bolts and stay-thimbles ³.
The movement of the telescope carrier R2 is balanced by counterpoise weights R
which are connected by means of the dependent arms R³ to the telescope circle R³,
and these weights are adjusted so that the centre of gravity of the telescope
and its various connections, will at all times lie in the vertical axis of the
instrument. These weights may be either fixed, as shown, or adjustably mounted,
on the arms R³.
Just above the sleeve Q, and revolubly mounted on the sleeve Q³, another
sleeve Q is provided.
To this sleeve Q, the brackets S and S¹ are rigidly attached. These brackets
are constructed of two side pieces s and s¹ connected together by ribs s². The
brackets S are shorter than the brackets s' being in the form of an arc of a circle,
This
and extending 65° on either side of the vertical axis of the instrument.
bracket indicates the latitude of the observer, and since this would rarely be
greater than 65° the range of the latitude circle or polar bracket is preferably
limited to 65°.
At right angles with this latitude circle S, the brackets S¹ are provided in the
upper ends of which are carried journal bearings for the journals E° of the
equatorial circle E. This equatorial circle is made in the form of a segment of a
sphere, concentric with the stellar globe W. The exterior surface of this equatorial
circle is graduated to 24 hours and each hour into 60 minutes, a vernier moving
over these gradations points the circle to be read to one second of time. Fixed
at right angles to this equatorial circle E is a meridian circle M, which carries,
at 90° from the central plane of the shaft bearings of the equatorial circle, a polar
axis, which axis revolubly supports the concentric stellar sphere, and the concentric
declination circle D graduated to degrees, minutes, &c.
It will be noted that the circles E, M, D and S are concentric with each other
and also with the stellar sphere while the centre of the circle H is in the same
vertical line with the common centre of the other circles.
The telescope is moved along this declination circle D the telescope carrier
bracket R2 swinging out of the perpendicular and the only limitation upon its travel
being the horizontal plane of equatorial shaft bearings,
The horizon or azimuth circle H being fixed at right angles to the vertical
axis of the instrument, is practically an artificial horizon; and the angle shown by
the vernier H', which is in the same vertical plane as the axis of the tele-
scope, indicates the azimuth of the body observed relative to the zero point of the
circle H.
This veruier H' operates in conjunction with an opposite arm H2 both fast to
the sleeve Q the said arm having a downwardly projecting lugh. A lower arm
encircles the sleeve Q³ as at H³ and is normally free to revolve thereon except
when held by the clamp screw 2. The fine motion is given to the vernier H' by
means of the tangent screw ³ which bears against one face of the lug h the other
face of the lug being borne against by the spring plunger he projecting from the
cylinder h' in which a coil spring not shown is mounted.
It will thus be seen that there is no lost motion between the screw h³ and the
lug This form of clamp however is not new and is not claimed as a part of my
invention.
The circle H is graduated to 180° on either side from the zero point. The plane
of the zero and 180° points is fixed to lie in the same vertical plane as that of the
meridian circle, and when the axis of the circle is exactly parallel with the ship's
keel, the sum of the angles indicated by the pointers C and C³ would be
exactly 180°
Should, however, the float N be a little out of the centre of the bowl F, as

page_text: would generally be the case, the sum of the angles indicated by the two pointers C
and C would be somewhat less than 180°, and the index correction for determining
the bearing of the ship's head would be one-half of the difference between the sum
of the observed angles and 180º.
Rigidly connected to one of its bearings E° of the equatorial circle E is an
arm E which carries a vernier e which travels along a graduated circle 5°
attached to or integral with one of the sides s of the latitude circle or polar
bracket S.
Adjustment for latitude, is given to the pole of the meridian circle M which is
fast to the equatorial circle E, by means of the clamp screw which clamps the
arm E on the opposite journal of the equatorial circle, which arm is given fine
motion by the tangent screw e which bears on one side of the arm E2, while the
spring plunger et bears on the other side of the said arm.
It will thus be seen that the pole of the meridian circle may be set at any
desired elevation by means of the said clamp and the vernier on the circle S will,
therefore, show the latitude.
The hour angle of the astronomical body is indicated by the angle that the
declination circle D makes with the meridian circle M. This declination circle is
revolubly connected by the bearings M° on the polar axis at points 180° apart on
the meridian circle M, and the angle between the two circles M and D is read by
a vernier similar to those already described travelling along the top of the equatorial
circle E, and connected to the declination circle D.
Fine motion is given to the declination circle by means of the clamp screw mo,
and the tangent screw' m² connected to the arm M¹ and operating similar to the
vernier attachments already described.
By placing these various vernier attachments in connection with journals of the
various circles, the graduated edges of these circles are left free for reading the
instrument, and also for the motion of the various parts travelling along or in
proximity to these outer surfaces.
The telescope carrier bracket R2 has rigidly attached thereto in a plane passing
through the vertical axis of the instrument a block T° in which is mounted a
mirror T
This mirror T2 is so set with relation to the axes of the tubes T' and T, that a
ray of light coming in the axis of the tube T¹ will be reflected by the mirror T2
in the axis of collimation of the telescope T, as indicated by the lines 1-2 and 2-3
of Fig. 5. The tube T¹ may be provided with a lens t³, while the telescope is
provided with the usual eye-piece T having lenses at to and t¹, and also with a
plurality of cross-hairs at the focus of the telescope t². These cross-hairs are
illuminated by a small electric light having wires to leading to a battery. The
electric light is placed at the base of the tube T3 connected to the telescope T as
shewn in Fig. 5. The battery should preferably be placed in the hollow portion of
the base of the pedestal, but this is immaterial. The cross-hairs are preferably
arranged as shewn in Fig. 6, that is with two central pairs of cross-hairs t' and to
crossing each other at a very small distance from the axis of the telescope, and
forming a small square enclosing this axis in its centre thereof.
This small square should preferably be about one square millimeter in area.
Outside of these two pairs of central cross-hairs are four groups of cross-hairs
of three each, indicated by 18, to, t, and t¹. These groups of cross-hairs form
three separate squares surrounding the axis of collimation of the telescope. The
cross-hairs are so arranged in the instrument that the smallest of these three squares
should be the inscribed square of the sun's disk at its smallest apparent diameter.
The outer square should be the circumscribed square of the sun's disk at its greatest
apparent diameter, while the intermediate square should be the inscribed square of
the sun's disk at its greatest apparent diameter.
The cross-hairs in the telescope are so arranged that half of them are always
carried in the exact horizontal plane while the others perpendicular to them, are

page_text: always in the vertical plane. The altitude of a heavenly body observed is
determined by the horizontal cross-hairs and its azimuth by the vertical cross-hairs.
If the observed body is not in the exact axis of the telescope its distance from the
axis will be measured by the distance from the horizontal and vertical cross-hairs
and hence by changing the elevation of the pole or the azimuth, respectively,
the body observed will be brought exactly in the plane of the axis of the
telescope.
When observing the sun a cap with a stained glass flat lens should be used to go
over the eye-piece T'.
The block To carrying the mirror and telescope is pivotally connected by means
of the lug Do to the block D' which has an overhanging lip adapted to engage
beneath the flange on the declination circle D, and at the same time to allow free
movement along said circle. Fine movement is given by means of the clamp
screw do, and the tangent screw d, which latter operates the vernier d' attached to
the block D', which moves with the block Tº.
W represents a hollow sphere on which most of the conspicuous stars are indicated
in their proper right ascension and declination, for the purpose of assisting the
observer in recognizing the star to be observed.
The method of taking observations with the instrument is as follows:-
1. Find from the Nautical Almanac the sun's declination for the Greenwich
apparent time.
2. Set the solarometer's declination arc to the sun's declination and latitude arc
to observer's approximate latitude.
3. Turn the solarometer in azimuth to the sun bringing the axis of the telescope
to the sun's altitude by changing in azimuth and elevation of the pole as necessary;
observe when the centre of the sun's disc is exactly in the axis of the telescope
and mark that second of time by the watch. At the same instant, advantageously
with an assistant, read the two opposite sides of the horizon circle under the two
pointers, which indicate the fore-and-aft line of the ship; subtract the sum of
these readings from 180° and add the half difference to the reading of the forward
pointer to find the ship's true course. The difference between this true course
and the compass course at the instant of the observation will be the compass error.
4. Record the solarometer readings of declination latitude, hour-angle, and
azimuth and compute the azimuth that corresponds to the first three quantities. from
the azimuth tables.
5. When the latitude, hour-angle and azimuth are all unknown it may be possible
to have the axis of the telescope at the sun's true altitude and these three quantities
may all be in error. By the construction of the instrument the telescope must
move in the plane of the path of the sun in the sky from rising to setting, if the
latitude is correct and allowance be made for changes in the sun's declination.
Proceed to take a second or a series of observations and it will be evident from the
results whether the movement of the telescope is in the plane of the sun's path.
If these results agree the telescope moved in that plane; if not, it moved in a
plane parallel but either too high or too low; the latitude must then be changed
according to the discrepancy, and by a series of observations the exact path of the
sun will be followed by the axis of the telescope. The final result is then certain
to be correct. With a series of observations it is important to allow for changes.
in the declination and observer's latitude if the time interval is considerable. If
either the latitude, hour-angle or azimuth is known, one observation will determine
the others.
6. For observations of a star or a planet, find from the almanac the star's right
ascension and declination and the night ascension of the mean sun for the Greenwich
mean time. Observe as with the sun, finding the local mean time from the star's
right ascension and the right ascension of the mean sun applied to the star's
hour-angle read from the solarometer. Record results and proceed as with the sun.
7. For observations of the moon proceed as with a star, carefully noting the
rapid change in the moon's declination. But it is not recommended to take

page_text: observations of the moon because of its change in declination and its horizontal
parallax.
8. By the mechanical support of the equatorial circle at the points six hours
from the meridian, the declination circle cannot revolve beyond those points; and the
shaft bearings at those points prevent observations when the hour-angle is between
5 and a and 6 and a hours from the local meridian. To observe a body which is
more than 6 hours from the local meridian, the telescope must be set to the sub-
polar declination and the hour-angle when (for example) east of the local meridian
must be read from the hour-circle on the west side and subtracted from 12 hours
to give the body's true hour-angle.
====
For the practical use of this instrument aboard ship it is essential that it be
provided with a suitable cover to protect the instrument from the wind, the weather
and the sea without any interposition of any refracting material between the object
glass and the heavenly body observed. The cover designed for this purpose is
arranged to permit an opening of any desired size to admit of a view of the heavens
from the horizon up to about 30° beyond the zenith, and by revolving the said cover
this opening may be given any desired bearing.
The various parts of the instrument supported on the column Q should be
as light as possible compared to the weight of the float, and for this purpose
they should be made of aluminium, channel ribbed metal or other light material.
Should it be desired one or more additional bowls similar to the bowl F and
contained therein may be added.
It is also purposed to use the solarometer for surveying on shore in which case
any level support permanent or temporary may be adopted in place of the float,
and mounted on said support beneath the circles would be provided a theodolite.
The azimuth circle would then serve as the horizon circle of a theodolite with the
telescope carried in a suitable frame beneath the same.
Moreover it will be evident that various other modifications of the herein
described apparatus, might be made which could be used without departing from
the spirit of my invention.
Having thus particularly ascertained and described the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The float provided with grooves on the exterior thereof adapted to engage in
the liquid, substantially as hereindescribed and shewn in Figs. 3 and 4 of the drawings
hereunto annexed,
2. The combination with an outer bowl mounted on gimbals, and containing a
heavy liquid, such as mercury, of an inner bowl floating in said liquid and itself
containing liquid, a float floating in the said liquid in the inner bowl, and apparatus
for making observations carried by said float, substantially as described.
3. The combination and arrangement of parts substantially as hereindescribed
and shewn in Figs. 3 and 4 of the drawings hereunto annexed.
4. The combination and arrangement of parts substantially as hereindescribed
and shewn in Figs. 1 and 2 of the drawings hereunto annexed.
5. The combination with the float and the azimuth circle carried thereby in the
plane of the horizon, of the pointers fixed relative to said float and in a given line
of bearing with the ship's keel, substantially as hereindescribed and shewn in the
drawings hereunto annexed.
6. The method of suspending the equatorial meridian, and declination circles
upon pivots connected to the equatorial circle at points 90° from the meridian
circle, substantially as hereindescribed and shewn in the drawings hereunto
annexed.
7. The combination with the telescope carrier bracket and the counterpoise
weights for balancing the same, of the declination circle and the sliding connection
between the telescope and the declination circle, substantially as hereindescribed
and shewn in the drawings hereunto annexed.

page_text: 8. The instrument for taking observations for determining a ship's position at
sea, substantially as hereindescribed and shewn in the drawings hereunto annexed.
Dated this 5th day of June 1894.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.