IMPROVEMENTS IN ASTRAL LANTERNS
Year: 1881

page_text: LETTERS PATENT to Franklin Henry Bailey, of Hillsdale, in the County of
Hillsdale, and State of Michigan, United States of America, for an Invention
of "IMPROVEMENTS IN ASTRAL LANTERNS."
COMPLETE SPECIFICATION filed by the said Franklin Henry Bailey at
the Office of the Commissioners of Patents on the 12th April 1881.
FRANKLIN HENRY BAILEY, of Hillsdale, in the County of Hillsdale, and State
of Michigan, in the United States of America. "IMPROVEMENTS IN ASTRAL
LANTERNS."
The object of this Invention is to facilitate the study of astronomy by furnishing
the student with an instrument that shall accomplish the work of an atlas of the
heavens, celestial globe, planisphere, and lantern for either day or night use. My
Invention consists of an apparatus for teaching astronomy, which I designate an
astral lantern, the same having adjustable maps of the heavens and other devices,
all of which will be fully understood by the following description:-The advantages
claimed for it are the ease and accuracy, and consequent saving of time in finding
the constellations and locating the stars, and following them in their course; also
the great saving to the eye in night use in being able to see the maps with all
their stars, boundaries of constellations, and names, by means of transmitted light,
so as not to affect the pupil of the eye, and in day use having a miniature heavens
seen by reflected light, presenting the stars in correct relative positions precisely
as they would appear in the heavens if visible. Without moving the instrument
when properly set the student, by changing his position, may see a map of that
part of the heavens which he faces, and with its stars all in the same relative
positions as those in the real heavens, the different magnitudes indicated and names
of principal stars given, the constellations bounded and names given, and every
map adjustable to every minute of time and every latitude north of the equator,
and by very simple mechanical movements each map is made to revolve or roll to
Thus the student is
keep exact pace with the apparent movement of the stars.
enabled to learn from this apparatus alone not only the names of the stars and
constellations but their exact position in the heavens at each minute, and their
exact movement, to tell the exact time of night, the latitude of his position of
..

page_text: observation, the exact time for the rising, culmination, and setting of each star, its
right ascension and declination or polar distance. I attain these objects by
mechanism illustrated in the accompanying Drawing, of which Figure 1 is a
perspective view showing the top and sides designated northern and western of
instrument; Figure 2 shows top with doors open, southern and eastern sides; Fig. 3
is a vertical sectional view on the line x, x, Figure 1, through the northern and
southern sides; and Fig. 4 a vertical sectional view on line y, y, through the
eastern and western sides. The instrument is provided with artificial light for
night use, and door B, gas escape G, and bail D. Its sides contain respectively
maps of the northern, eastern, southern, and western heavens mounted and
described as follows:-The northern and southern heavens, each being represented
by a circular map E, E', fastened to or otherwise placed on glass discs C, C, Fig. 3,
a little larger that the map, and having near its margin the date at which each
part of the map should be uppermost at nine o'clock p.m., and by means of
which it is adjusted to the time dial by bringing under 9 p.m. on the dial, said time
dial being upon the margin of another glass disc H, H, Figs. 2, 3, and 4, of the
same size as the one carrying the map. Both glass discs revolving together upon
friction rollers I, Figure 4, by means of thumb pieces J, the map is set for any
hour or minute of the day by bringing the time at which it is desired to set it into
the slot n over the map in plate K.
The glass discs, carrying the map and time dial, are held in place in the sides of
the lantern by means of two plates K, Figs. 1 and 2, and K¹, Figs. 2 and 4, with
circular openings M through which the map is visible, said plates being provided
with adjustable horizons O sliding in grooves P, and perforated pivoted
indicators Q, Q'; on a bar R sliding also in said grooves for showing right
ascension and declination or polar distance. Each of the eastern and western
sides has a rolling printed or written map S in the form of a portion of the sector
of a circle between two concentric arcs of unequal radii mounted on frustums of
cones T with thumb screws v for revolving the same enclosed in sheaths V in
combination with glass plate W, with a perforated sliding indicator X for showing
right ascension and declination or polar distance, and revolving disc Y provided
with handles and having opening of same form as map provided with slot a in
larger curvature for showing date; said disc revolving against a plate b having a
rectangular opening e, Fig. 3, covered with ground glass g, Fig. 3, and provided
with a stationary horizon d. The map of the northern heavens embraces that
portion containing the visible stars within a radius of fifty degrees of the pole, and
the map of the southern heavens that portion containing the visible stars within
ninety degrees of the pole. The remaining portions, together with five degrees of
both the northern and southern heavens, is embraced in both the eastern and
western maps. Instead of the maps being revolved by hand, clockwork may be
employed for that purpose. In operating my Invention I place the lantern square
with the points of the compass with the map of the northern heavens, facing the south.
Select northern and southern horizons corresponding with the latitude of observation
and place them in the appropriate grooves, loosen the screws at top of disc on
eastern and western sides, revolve the discs until their arrows point toward their
figures indicating the correct latitude, revolve the maps on the northern and
southern dial plates until the date appears directly under IX. p.m., turn thumb
screws until the time of observation or time of study in either day or night appears
under notches in slots at top of openings. Roll the eastern and western maps by
means of the thumb screws or ends of rollers until the correct date appears at
lower end of slots in plates. The maps will then be set for nine o'clock p.m. If
the time of observation or study is earlier than nine o'clock roll the maps backward,
and forward if the time is later, at the rate of fifteen degrees per hour. The
lantern being thus set, the observer compares the real with the miniature heavens,
and is thereby enabled to readily apply to the stars and constellations the names
they bear upon the maps. By revolving and rolling the maps he is enabled to keep
the stars and constellations in the miniature in the same relative positions as they

page_text: appear in the real heavens, and by reference to the dial on margin of map either
the northern or southern heavens can determine the exact time.
The pivoted
indicators can be used to determine right ascension, declination or polar distance,
and time of culmination of the stars. Right ascension is read by reference to
figures on inner margin of maps, declination or polar distance by reference to figures
on indicators, and time of culmination by figures on dial under indicator when
placed perpendicularly with edge over notches in slots. To determine right ascension
and declination or polar distance of stars on eastern and western maps I place the
sliding indicator on glass plate with either edge, as the case may be, over star
and corresponding figures on both margins, which by means of the straight edge
indicator will show the right ascension or declination sought for.
Having thus described my Invention, what I claim is,-
1st. In an apparatus for teaching astronomy the frustum rollers T for the purpose
of rolling and adjusting the map S, substantially as specified.
2nd. The revolving disc Y in combination with the map S and rollers T,
substantially as set forth.
3rd. The annular revolving time dial F, F¹, mounted as described in combination
with revolving circular maps E, E, of glass or other translucent material, sub-
stantially as set forth.
4th. In an apparatus for teaching astronomy the friction rollers I for the purpose
of adjusting the revolving maps and dials, as set forth.
5th. In an apparatus for teaching astronomy the series of exchangeable horizon
plates O, substantially as specified.
6th. The indicator Q constructed and arranged, substantially as described, to
indicate right ascension, declination, and time of culmination, substantially as
specified.
7th. The slots n in combination with the revolving maps E, E¹, for the purpose
of indicating the time on the dial, substantially as set forth.
8th. In an apparatus for teaching astronomy the rollers I and frustums of
cones T, T, for the purpose of revolving the maps of northern and southern, and of
eastern and western heavens respectively, substantially as set forth.
In witness whereof, I, the said Franklin Henry Bailey, have hereunto set
my hand and seal, this Twelfth day of April, in the year of our Lord One
thousand eight hundred and eighty one.
DAILEY.
(L.S.)
TATATOTT UTXTAT SATT