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TELESCOPTICS
A Monthly Department for the Amateur Telescope Maker
Conducted by ALBERT G. INGALLS
like thousands of other mor-
fication is sun-dialling, and under sun-
are now making their own
dialling come sun-clocks. Just what
telescopes. From the Society of the
is a sun-clock?
Divine Word, Techny, Illinois, comes
Invented by W. E. Cooke, govern-
the following:
ment astronomer of New South Wales,
"Even in the crowded curriculum
Australia, the sun-clock was described
of studies at St. Mary's Major Semin-
in this magazine in August, 1928, also
ary, astronomy has its place and holds
August, 1935, by R. W. Porter. A ring,
an attraction for many a student. Its
or sometimes a C-shaped portion of
a ring (Figure 2), carries a
lens on the sunward side,
and on the other an anal-
emma, the familiar 8-
shaped curve of the equa-
tion of time. By turning a
thumbnut with the fingers,
until the Sun's image falls
exactly on the analemma,
hands taken from an ordi-
nary clock are mechanic-
ally actuated through gear
Figure 3: Ferson's sun-clock
trains and the standard
time is read on the clock
box and clock face and big, curved,
dial-direct and not by a
rotatable fork. The fork has in its
shadow, as in a sun-dial.
upper horn a slot in which is mounted
There is, of course, no run-
a little lens of 8" f.l. The analemma
ning clock movement.
is inscribed on a sheet brass plate
Working from the ar-
bent to a radius equal to the f.l. of the
ticles by Porter, cited above,
lens (its radius of curvature is there-
Figure 1: Astronomy class, St. Mary's
Fred Ferson, 414 Reynoir
fore nearly twice that of the fork-
Street, Biloxi, Mississippi,
study Figure 7 if "nearly" is not at
study serves a definitely practical pur-
has made the sun-clock shown in
first clear) and attached to the lower
pose, since most of the seminarians
Figure 3, and states that "careful
horn. To find the time at any desired
will one day labor in foreign mission
construction and adjustment afford
moment the large thumbnut extend-
fields, where astronomical knowledge
time within one minute, likewise
ing, in Figure 3, below and to the left
will supply in many ways what these
the date. The base casting has four
of the gear box is turned with the
primitive countries do not-aids in
leveling screws and carries a sec-
fingers, and gears with ratio 1, 2, and
regard to time, in regard to nautical
ond casting which supports in a
24 do the rest; that is, 24 revolutions
determinations, in surveying, and in
curved slot a short, stubby, curved
of the handwheel will rotate the min-
exploration, to mention but a few.
main standing arm. This can be slid
ute hand 24 times, the hour hand
"A few years ago an observatory
circularly and clamped for latitude.
twice, and the fork once. When the
(Figure 1) was built at Techny, hous-
At the end of this stubby arm is a
Sun's image is made to bisect the
ing a 110 mm. refractor, a comet-
rigid, hollow stud carrying the gear
analemma curve the clock hands will
seeker, the structure having been de-
automatically point to the hour and
signed and constructed by the Brother
minute, also giving the date." Fer-
Monks. But this telescope soon proved
son will lend further details of con-
inadequate for the interest and en-
struction to those seriously interested.
thusiasm of the star-gazers, and it was
Even now, more than a decade after
deemed advisable to construct a larger
he made his first sun-clock (Figure: 2),
one, 8" in aperture, the work being
Porter still composes new variations
done under the direction of Father
on the original theme and then makes
Francis Neuhaus, S. V. D., one of the
the clocks. Figure 4 is one of these,
seminarians. Meanwhile, Brother Cor-
as set up in his door-yard at Pasadena.
sinus, S. V. D., an able mechanic, was
"It consists," he writes, "first, of a
busy constructing a well-balanced
spherical Pyrex flask carrying all the
mounting, shown in the center. With
optical parts and the clock face, on
a surprising minimum of cost, the re-
which is also engraved the analemma.
flector was completed, and now serves
The entire unit is encircled by a
to great advantage, not only to bring
grooved equatorial ring sliding on a
more of the heavens within grasp, so
segment below, which is fastened to
to say, of the students of astronomy,
the base. The equatorial gear used
but also to render celestial photog-
was a 32-pitch rack bent to fit the
raphy possible because of the new
groove of the equatorial ring.
telescope's greater light - gathering
"In adjusting the polar axis paral-
power.
lel to that of the Earth, a tubeless
"Work on a 12¹/2" mirror for a still
telescope, consisting of an eyepiece
larger telescope is now under way."
and objective, is fastened to the sphere
at the poles of the encircling equa-
A
MATEUR telescopticians, ten or
torial ring. The field of view of the
twenty thousands of them, have
eyepiece contains just the apparent
now felt their way into about all the
orbit of Polaris about the true pole;
related arteries and capillaries of op-
so that, by estimating the hour angle
tics and astronomy. One such rami-
Figure 2: Porter, sun-clock
of Polaris by the stars in the Big Dip-
per and Cassiopeia, and using the base
106
SCIENTIFIC AMERICAN
AUGUST 1940
Document source description
This item contains an excerpt about telescoptics from Scientific American Magazine.
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"ocrText": "TELESCOPTICS\nA Monthly Department for the Amateur Telescope Maker\nConducted by ALBERT G. INGALLS\nlike thousands of other mor-\nfication is sun-dialling, and under sun-\nare now making their own\ndialling come sun-clocks. Just what\ntelescopes. From the Society of the\nis a sun-clock?\nDivine Word, Techny, Illinois, comes\nInvented by W. E. Cooke, govern-\nthe following:\nment astronomer of New South Wales,\n\"Even in the crowded curriculum\nAustralia, the sun-clock was described\nof studies at St. Mary's Major Semin-\nin this magazine in August, 1928, also\nary, astronomy has its place and holds\nAugust, 1935, by R. W. Porter. A ring,\nan attraction for many a student. Its\nor sometimes a C-shaped portion of\na ring (Figure 2), carries a\nlens on the sunward side,\nand on the other an anal-\nemma, the familiar 8-\nshaped curve of the equa-\ntion of time. By turning a\nthumbnut with the fingers,\nuntil the Sun's image falls\nexactly on the analemma,\nhands taken from an ordi-\nnary clock are mechanic-\nally actuated through gear\nFigure 3: Ferson's sun-clock\ntrains and the standard\ntime is read on the clock\nbox and clock face and big, curved,\ndial-direct and not by a\nrotatable fork. The fork has in its\nshadow, as in a sun-dial.\nupper horn a slot in which is mounted\nThere is, of course, no run-\na little lens of 8\" f.l. The analemma\nning clock movement.\nis inscribed on a sheet brass plate\nWorking from the ar-\nbent to a radius equal to the f.l. of the\nticles by Porter, cited above,\nlens (its radius of curvature is there-\nFigure 1: Astronomy class, St. Mary's\nFred Ferson, 414 Reynoir\nfore nearly twice that of the fork-\nStreet, Biloxi, Mississippi,\nstudy Figure 7 if \"nearly\" is not at\nstudy serves a definitely practical pur-\nhas made the sun-clock shown in\nfirst clear) and attached to the lower\npose, since most of the seminarians\nFigure 3, and states that \"careful\nhorn. To find the time at any desired\nwill one day labor in foreign mission\nconstruction and adjustment afford\nmoment the large thumbnut extend-\nfields, where astronomical knowledge\ntime within one minute, likewise\ning, in Figure 3, below and to the left\nwill supply in many ways what these\nthe date. The base casting has four\nof the gear box is turned with the\nprimitive countries do not-aids in\nleveling screws and carries a sec-\nfingers, and gears with ratio 1, 2, and\nregard to time, in regard to nautical\nond casting which supports in a\n24 do the rest; that is, 24 revolutions\ndeterminations, in surveying, and in\ncurved slot a short, stubby, curved\nof the handwheel will rotate the min-\nexploration, to mention but a few.\nmain standing arm. This can be slid\nute hand 24 times, the hour hand\n\"A few years ago an observatory\ncircularly and clamped for latitude.\ntwice, and the fork once. When the\n(Figure 1) was built at Techny, hous-\nAt the end of this stubby arm is a\nSun's image is made to bisect the\ning a 110 mm. refractor, a comet-\nrigid, hollow stud carrying the gear\nanalemma curve the clock hands will\nseeker, the structure having been de-\nautomatically point to the hour and\nsigned and constructed by the Brother\nminute, also giving the date.\" Fer-\nMonks. But this telescope soon proved\nson will lend further details of con-\ninadequate for the interest and en-\nstruction to those seriously interested.\nthusiasm of the star-gazers, and it was\nEven now, more than a decade after\ndeemed advisable to construct a larger\nhe made his first sun-clock (Figure: 2),\none, 8\" in aperture, the work being\nPorter still composes new variations\ndone under the direction of Father\non the original theme and then makes\nFrancis Neuhaus, S. V. D., one of the\nthe clocks. Figure 4 is one of these,\nseminarians. Meanwhile, Brother Cor-\nas set up in his door-yard at Pasadena.\nsinus, S. V. D., an able mechanic, was\n\"It consists,\" he writes, \"first, of a\nbusy constructing a well-balanced\nspherical Pyrex flask carrying all the\nmounting, shown in the center. With\noptical parts and the clock face, on\na surprising minimum of cost, the re-\nwhich is also engraved the analemma.\nflector was completed, and now serves\nThe entire unit is encircled by a\nto great advantage, not only to bring\ngrooved equatorial ring sliding on a\nmore of the heavens within grasp, so\nsegment below, which is fastened to\nto say, of the students of astronomy,\nthe base. The equatorial gear used\nbut also to render celestial photog-\nwas a 32-pitch rack bent to fit the\nraphy possible because of the new\ngroove of the equatorial ring.\ntelescope's greater light - gathering\n\"In adjusting the polar axis paral-\npower.\nlel to that of the Earth, a tubeless\n\"Work on a 12¹/2\" mirror for a still\ntelescope, consisting of an eyepiece\nlarger telescope is now under way.\"\nand objective, is fastened to the sphere\nat the poles of the encircling equa-\nA\nMATEUR telescopticians, ten or\ntorial ring. The field of view of the\ntwenty thousands of them, have\neyepiece contains just the apparent\nnow felt their way into about all the\norbit of Polaris about the true pole;\nrelated arteries and capillaries of op-\nso that, by estimating the hour angle\ntics and astronomy. One such rami-\nFigure 2: Porter, sun-clock\nof Polaris by the stars in the Big Dip-\nper and Cassiopeia, and using the base\n106\nSCIENTIFIC AMERICAN\nAUGUST 1940"
}