Apparatus for photographing meteors in a selected area of the sky is described. A photomultiplier is pointed in the direction of the area. When a meteor passes through the area the signal output of the photomultiplier increases. Means are provided that activate a camera, pointed at the area, in response to an increased signal from the photomultiplier. Hence, the camera photographs the selected are only while meteors are likely to be passing through the area

Harvey, G. A.

English

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NATIONAL AERONAUTICS AND SPACE ADMlNISf RAT ION
WASHINGTON. D.C. 205«6
N73-19419
REPLY TO
ATTN OF: \3C
-TO i
PHOTOGRAPHING HETEOBS
P
.SC1
Unclas
00/14 J>0780__
PROMs
RSI/Scientific & Technical Information Division
Attentions Miss Winnie M. Morgan
GP /Off ice of Assistant General Counsel for
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NASA patent Case No.
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NOTE - If this patent covers an invention made by a corporate
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Elizabeth A. carter
Enclosure
Copy of patent cited above
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https://ntrs.nasa.gov/search.jsp?R=19730010692 2020-03-17T08:24:40+00:00Z
United States Patent
Harvey
3,712,195
Jan. 23, 1973
154] APPARATUS FOR PHOTOGRAPHING
METEORS
[75] Inventor: Gale A. Harvey, Hampton, Va.
[73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration
[22] Filed: Dec. 16, 1970
[21] Appl. No.: 98,774
[52] U.S.CI 95/11 R, 95/11.5 R, 250/217 R
[51] Int. Cl G03b 19/02
[58] Field of Search 95/11, 11.5,4.5, 12.5,53 E;
250/217 R
[56] References Cited
UNITED STATES PATENTS
2,927,215 3/1960 Allen et al 250/217 R
2,419,978 5/1947
3,019,292 1/1962
3,093,047 6/1963
Wildman ........................... 95/1 1.5 A
John .............................. .-...95/12.5 X
Neff ...................................... 95/53 E
Primary Examiner — Samuel S. Matthews
Assistant Examiner— Kenneth C. Hutchison
Attorney— Howard J. Osborn, William H. King and
John R. Manning
[57] ABSTRACT
Apparatus for photographing meteors in a selected
area of the sky only at times meteors are likely to be
passing through the area. A photomultiplier is pointed
in the direction of the area. When a meteor passes
through the area the signal output of the photomul-
tiplier increases. Means are provided that activates a
camera, pointed at said area, in response to an in-
creased signal from the photomultiplier. Hence, the
camera photographs the selected area only while
meteors are likely to be passing through the area.
2 Claims, 1 Drawing Figure
30_ 14
30 16
19
-13
30
PATENTED JAN 2 3 1973 3.712,195
BY
JNVENTOR.
GALE A. HARVEY
ATTORNPTS
3,712,195
1 2
APPARATUS FOR PHOTOGRAPHING METEORS shaft 19 of rotary solenoid 17 is coupled to shutter 13
ORIGIN OF THF DISCI OSIIRF SUCh ^ Whe" * V°^g* ™ aPpl'ed l° ^^ SolenoidORIOIN OFTHfc DISCLOSURE
 17 shaft ,9 rotates and rotates shutter 13 out of the
The invention described herein was made by an em- path of the light that passes through diffraction grating
ployee of the United States Government and may be 5 12. The input of rotary solenoid 17 is connected to one
manufactured and used by or for the Government for of the contacts 20 of a relay 21. The other contact 20 is
governmental purposes without the payment of royal- connected through a variable resistor 22 to a 45 volt
ties thereon or therefor. power source 23. Capacitor 24 which is capable of
charging to 45 volts is connected between ground and
BACKGROUND OF THE INVENTION 10
 the junction of resistor 22 and contacts 20 Capacitor
The invention relates generally to photography and 24 can be a bank of capacitors instead of a single
more specifically concerns photographing meteors in a capacitor as shown. The purpose of capacitor 24 is to
selected area of the sky. apply a large current to rotary solenoid 17 the instant
The prior art of photographing meteors points a ,5 contacts 20 close to overcome the inertia of shutter 13
camera in the direction of the selected area in the sky and make it fast-acting. The purpose of variable re-
to be photographed and then continuously exposes the sistor 22 is to keep the voltage across rotary solenoid
film in the camera. The disadvantages of the prior art 17 constant at about 6 volts after capacitor 24 is
are that when a framing camera is used the film has to discharged. A photomultiplier 25 has its power supply
be continuously cycled (in a framing mode) through 20 26 connected to it through a variable resistor 27. The
the camera and when the film is on plates the plates output of photomultiplier 25 is connected through an
have to be changed every 30 seconds to 5 minutes amplifier 28 to the coil 29 of relay 21. The purpose of
because of night sky radiation and starlight. Also the variable resistor 27 is to vary the sensitivity of
prior art devices cannot be operated on nights when the photomultiplier 25 so that the contacts 20 of relay 21
moon is up and they have a low ratio of meteors photo- 25 will close at some predetermined intensity of light corn-
graphed to film exposed. It is therefore the primary ing into the photomultiplier.
purpose of this invention to provide apparatus for In the operation of this invention film is placed on
photographing meteors in which the film is exposed the focal surface 16 of camera 11 and the camera is
only while meteors are likely to pass through the area in pointed so that it covers the selected area in the sky to
the sky being photographed. 30 be photographed. We will assume initially that there
„.,»,,-. „„ ~-~..^ ,»,.,^»,~,.~,.,
 are no
 meteors in the area, then the light rays 30 fromSUMMARY OF THE INVENTION ^
 se,ected afea are b,ocked by shu«er J Variab,e
The invention consists essentially of a camera and a resistor 27 is adjusted so that a meteor with a predeter-
photomultiplier pointed in the direction of the area in mined light intensity will cause photomultiplier 25 to
the sky to be photographed. When a meteor is in this produce a signal large enough to actuate relay 21.
area the resulting increase in light intensity causes the Photomultiplier 24 is then pointed so that it covers the
photomultiplier to produce an increased electrical selected area in the sky. Inasmuch as there is no meteor
signal. Means are provided which are responsive to this in the area selected to be photographed, the contacts
increased signal for opening the shutter of the camera.
 4Q 20 are open as shown, the shutter 13 is closed and
When the electrical signal decreases back to its normal blocks light rays 30 and the capacitor 24 is charged to
value, the shutter closes. Hence, the film in the camera 45 volts. At the instant a meteor moves into the
is exposed only while a meteor is in the selected area of selected area the light rays 30 from this area causes
the sky. The means for opening the shutter includes a photomultiplier 25 to produce a signal with a mag-
relay which has the electrical signal from the photomul-
 45 nitude sufficient to actuate relay 21 to close contacts
tiplier applied to its coil. When the electrical signal in- 20. This applies the 45 volt charge on capacitor 24 to
creases to a predetermined value the contacts of the rotary solenoid 17 causing shutter 13 to open im-
relay close and apply a voltage to a rotary solenoid. mediately. The light rays 30 then pass through the cor-
This solenoid has its shaft coupled to the shutter of the rector lens 14 and are reflected back onto the film on
camera to open the shutter while voltage is applied to 50 focal surface 16 forming an image of the meteor on the
the solenoid. Capacitor means are provided to apply a flim. When the meteor moves out of the selected area,
large current to the solenoid at the instant the contacts photomultiplier 25 does not produce a signal large
of the relay close to overcome the inertia of the shutter enough to hold the contacts 20 of relay 21 closed,
thereby making the shutter open faster. Hence, contacts 20 open, shaft 19 of rotary solenoid 17
BRIEF DESCRIPTION OF THE DRAWING " m*tes back to its ^ginal position closing shutter 13.
and a capacitor 24 again charges to 45 volts. Con-
The sole FIGURE in the drawing is a schematic dia- sequently the film in the camera is exposed only when a
gram of the embodiment of the invention selected for meteor is in the area of the sky being photographed,
illustration. The advantage of this invention is that it provides a
DFTAII ED DESCRIPTION OF THE INVENTION 6° Simple> inexPensive means for photographing meteorsDETAILED DESCRIPTION F THE IN VENI ION
 jf) whjch ^ film jg exposed on|y when there {s a meteor
Turning now to the embodiment of the invention in the area in the sky being photographed,
selected for illustration in the drawing, the number 11 It is to be understood that the form of the invention
designates a camera. Camera 11 includes a diffraction herewith shown and described is to be taken as a
grating 12, a shutter 13, a corrector lens 14, a primary preferred embodiment. Various changes may be made
mirror 15 and a focal surface 16. A rotary solenoid 17 without departing from the spirit or scope of the inven-
is attached to camera 11 by any suitable means 18. The tion as defined in the subjoined claims. For example, an
3,712,195
internal iris-type shutter could be used instead of a
blade-rotary solenoid shutter. Different fields of view
(20°, 30°, 40°); different apertures (3% inches, 5
inches, 6 inches, 8 inches); and different color filters on
the photomultiplier tube could be used.
What is claimed as new and desired to be secured by
Letters Patent of the United States is:
1. Apparatus for photographing meteors in a selected
area of the sky comprising: means for producing an
electrical signal proportional to the intensity of light
emanating from said selected area of the sky; means for
photographing said selected area of the sky while ac-
tivated including a shutter, a rotary solenoid attached
to the shutter for rotating the shutter whenever power
is applied to the rotary solenoid, a power source, a
relay having its coil connected to said means for
producing an electrical signal and having its contacts
connected between said power supply and said rotary
solenoid, and capacitor means connected between the
junction of said contacts and said power supply so that
it is charged while said contacts are open whereby
whenever the intensity of said light exceeds said
predetermined value said contacts close applying a
large surge of current to said rotary solenoid to cause it
to rapidly operate said shutter; and means responsive to
said electrical signal for activating said photographing
means while the amplitude of said electrical signal ex-
ceeds a predetermined value whereby said photogra-
phing means photographs said selected area of the sky
only at times meteors are likely to be passing through
said selected area.
2. Apparatus according to claim 1 including a varia-
.
 5 ble resistor connected between said power supply and
said capacitor means for regulating the voltage applied
across said rotary solenoid while said contacts are
closed.
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Apparatus for photographing meteors

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