U.S. patent application number 10/438127 was filed with the patent office on 2004-11-25 for automatic telescope.
Invention is credited to McWilliams, Rick.
Application Number | 20040233521 10/438127 |
Document ID | / |
Family ID | 33449732 |
Filed Date | 2004-11-25 |
United States Patent
Application |
20040233521 |
Kind Code |
A1 |
McWilliams, Rick |
November 25, 2004 |
Automatic telescope
Abstract
An automatic telescope (10) capable of determining an
orientation without requiring input from a user or any external
source. The telescope (10) preferably includes a database (22) to
store astronomical information, a processor (24) to control a drive
mechanism (18), a vision device (30) to sense bright stars, and a
motion sensor (32) to generate a motion signal. When the vision
device (30) is slewed from alignment with a first bright star to a
second bright star, the motion signal is preferably representative
of a measured angle between the first and second bright stars. This
process is preferably repeated for several bright stars to generate
several measured angles. The processor (24) can then use the
measured angles to identify the bright stars and determine the
orientation of the telescope (10).
Inventors: |
McWilliams, Rick; (Ventura,
CA) |
Correspondence
Address: |
THOMAS B. LUEBBERING
HOVEY WILLIAMS LLP
Suite 400
2405 Grand
Kansas City
MO
64108
US
|
Family ID: |
33449732 |
Appl. No.: |
10/438127 |
Filed: |
May 14, 2003 |
Current U.S.
Class: |
359/399 |
Current CPC
Class: |
Y10S 359/90 20130101;
G02B 23/00 20130101; G02B 23/16 20130101 |
Class at
Publication: |
359/399 |
International
Class: |
G02B 023/00 |
Claims
Having thus described a preferred embodiment of the invention, what
is claimed as new and desired to be protected by Letters Patent
includes the following:
1. An automatic telescope operable to determine an orientation, the
telescope comprising: a vision device operable to sense bright
stars; a base operable to support the vision device; a cradle
attached to the base and operable to movably support the vision
device with respect to the base; a drive mechanism operable to move
the cradle with respect to the base; and a processor operable to
control the drive mechanism in order to determine the orientation
of the vision device using a vision signal from the vision
device.
2. The telescope as set forth in claim 1, wherein the vision device
is a CCD camera operable to generate a vision signal representative
of the bright stars.
3. The telescope as set forth in claim 1, further including a
database operable to contain information relating to a plurality of
known stars.
4. The telescope as set forth in claim 3, wherein the processor is
further operable to determine the orientation of the telescope by
comparing measured angles between the bright stars with the
information stored in the database.
5. The telescope as set forth in claim 3, wherein each bright star
is sensed by analyzing the vision signal received from the vision
device.
6. The telescope as set forth in claim 3, further including a
motion sensor operable to detect the measured angles between the
bright stars as the vision device is slewed from alignment with one
of the bright stars to another of the bright stars.
7. The telescope as set forth in claim 1, further including a
motion sensor operable to sense motion of the telescope.
8. The telescope as set forth in claim 7, wherein the motion sensor
is operable to sense motion along a first and second axis of
motion.
9. The telescope as set forth in claim 7, wherein the processor is
further operable detect the measured angles using a motion signal
from the motion sensor as the vision device is slewed from
alignment with one of the bright stars to another of the bright
stars.
10. The telescope as set forth in claim 1, wherein the processor is
further operable to control the drive mechanism in order to align
the telescope with a specified star.
11. A method of determining a telescope's orientation, the method
comprising the steps of: sensing a first bright star using a vision
device; sensing a second bright star using the vision device;
detecting a first measured angle between the first bright star and
the second bright star; sensing a third bright star using the
vision device; detecting a second measured angle between the second
bright star and the third bright star; comparing the measured
angles with central angles stored in a database, thereby
identifying the bright stars; and determining the orientation of
the telescope by analyzing known locations of the bright stars.
12. The method as set forth in claim 11, further comprising
detecting a third measured angle between the third bright star and
the first bright star.
13. The method as set forth in claim 11, wherein at least four
bright stars and six measured angles are used to determine the
orientation of the telescope.
14. The method as set forth in claim 11, further including the step
of receiving an identity of a specified star.
15. The method as set forth in claim 14, further including the step
of retrieving the specified star's location from the database.
16. The method as set forth in claim 15, further including the step
of comparing the location of the specified star with the
orientation of the telescope in order to align the telescope with
the specified star.
17. The method as set forth in claim 16, further including the step
of aligning the telescope with the specified star.
18. The method as set forth in claim 17, further including the step
of using signals received from the vision device to substantially
center the specified star within the telescope's field of view.
19. The method as set forth in claim 11, wherein the measured
angles are measured by monitoring motion as the telescope is slewed
between the bright stars.
20. A method of displaying a specified star through a telescope,
the method comprising the steps of: sensing a first bright star
using a vision device; aligning the telescope with the first bright
star; sensing a second bright star using the vision device;
monitoring motion as the telescope is slewed from alignment with
the first bright star to the second bright star; detecting a first
measured angle between the first bright star and the second bright
star; sensing a third bright star using the vision device; aligning
the telescope with the second bright star; monitoring motion as the
telescope is slewed from alignment with the second bright star to
the third bright star; detecting a second measured angle between
the second bright star and the third bright star; monitoring motion
as the telescope is slewed from alignment with the third bright
star to the first bright star; aligning the telescope with the
first bright star; detecting a third measured angle between the
third bright star and the first bright star; comparing the measured
angles with central angles stored in a database, thereby
identifying the bright stars; determining the orientation of the
telescope by analyzing known locations of the bright stars;
receiving indication of a specified star; retrieving the specified
star's location from the database; and aligning the telescope with
the specified star.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to telescopes. More
particularly, the present invention relates to an automatic
telescope that can align itself in order to view a specified
star.
[0003] 2. Description of Prior Art
[0004] Many telescopes are capable of finding and tracking stars
and other celestial bodies. However, these telescopes must be
initially oriented and re-oriented each time they are moved.
Therefore, users are typically required to provide such telescopes
with orientation information, such as an altitude angle and an
azimuth angle. Unfortunately, many users are not familiar with or
do not want to be bothered with providing such information.
[0005] Additionally, such telescopes typically only have small
hard-to-use interfaces, such as handheld remote controls. While
these remote controls are adequate for some purposes, they can be
difficult to use, further increasing the inconvenience of providing
orientation information.
[0006] Accordingly, there is a need for an improved automatic
telescope that overcomes the limitations of the prior art.
SUMMARY OF THE INVENTION
[0007] The present invention overcomes the above-identified
problems and provides a distinct advance in the art of telescopes.
More particularly, the present invention provides an automatic
telescope capable of determining an orientation without requiring
input from a user or an external source. Additionally, the
telescope may automatically align itself with virtually any star,
planet, or other celestial object specified by the user. The
telescope broadly comprises an optical telescopic tube for
magnifying distant objects, a base for supporting the tube, a
cradle for securing the tube to the base, a drive mechanism for
moving the tube with respect to the base, and a control unit to
control the drive mechanism.
[0008] The control unit preferably includes a database to store
astronomical information and a processor to align the tube with the
specified star using the drive mechanism. The database preferably
includes information about stars, planets, and other celestial
objects, such as nebulae. The information preferably includes
location information and details relating to each celestial object,
such as position, size, magnitude, type of object, and
identification information.
[0009] The control unit also preferably includes a vision device to
electronically sense bright stars and a motion sensor to sense
motion of the tube of the telescope. The vision device is
preferably securely aligned with the tube and may be secured to the
tube or the cradle. The vision device preferably generates a vision
signal representative of an image in the vision device's field of
view. Therefore, when the tube and the vision device are pointed at
a first bright star, the vision signal is representative of the
first bright star.
[0010] Similarly, the motion sensor is preferably securely aligned
with the tube and may be secured to the tube or the cradle. The
motion sensor preferably generates a motion signal representative
of changes in altitude and azimuth angles of the tube. Therefore,
as the tube is slewed from alignment with the first bright star to
a second bright star, the motion signal is preferably
representative of that motion comprising the changes in the
altitude and azimuth angles between the first bright star and the
second bright star. The changes in the altitude and azimuth angles
constitute a measured angle between the first bright star and the
second bright star.
[0011] In use, a user initializes the telescope by turning on the
telescope, pressing one of a plurality of buttons of the control
unit, or simply supplying power. Upon initialization, the processor
directs the drive mechanism to scan the sky until the vision device
senses the first bright star. The first bright star is then
substantially centered within the vision device's field of view and
the motion signal is initialized.
[0012] It is important to note that, as used here, the first bright
star does not relate to any specific star. The first bright star
only implies that the first bright star is actually sensed first,
upon initialization. As such, the first bright star may actually be
a different star each time the telescope is initialized.
Furthermore, the first bright star may actually be a planet or
another celestial object that is brighter than surrounding space.
The same principal applies to the second bright star and any other
bright stars sensed by the telescope.
[0013] After initializing the motion signal, the processor directs
the drive mechanism to scan the sky in search of the second bright
star. Once the vision device has sensed the second bright star, the
processor fine tunes the drive mechanism to substantially center
the second bright star in the vision device's field of view. The
processor then copies the measured angle from the motion signal.
This process is preferably repeated until several measured angles
provide a unique solution, from which the orientation of the
telescope may be determined.
[0014] For example, the processor compares the measured angles with
a matrix stored in the database to determine the orientation of the
telescope. Specifically, when the processor matches the measured
angles with a portion of the matrix, the bright stars associated
with the measured angles have been identified. Once the bright
stars are identified, the processor can use the location
information of the bright stars to determine the orientation of the
telescope. It is important to note that the user has not been
required to provide any information to the telescope, such as
location, orientation, or date.
[0015] Once the orientation is known, the processor may then find
virtually any star or other celestial object specified by a user.
For example, the user preferably identifies a specified star using
buttons of the control unit. The processor searches the database to
find location information for the specified star. The processor
then instructs the drive mechanism to align the tube with the
specified star. The processor may use the vision signal to fine
tune the drive mechanism in order to substantially center the
specified star within the tube's field of view.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] A preferred embodiment of the present invention is described
in detail below with reference to the attached drawing figures,
wherein:
[0017] FIG. 1 is a perspective view of a preferred embodiment of an
automatic telescope of the present invention;
[0018] FIG. 2 is a block diagram of a control unit of the
telescope;
[0019] FIG. 3 is a portion of a matrix comprising central angles
between known stars that may be used by and stored in the control
unit;
[0020] FIG. 4 is flow chart showing a preferred orientation
determination procedure used by the telescope; and
[0021] FIG. 5 is flow chart showing a preferred star tracking
procedure used by the telescope.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
[0022] Referring to FIG. 1, the preferred automatic telescope 10
constructed in accordance with a preferred embodiment of the
present invention is illustrated as a stand-alone system capable of
determining an orientation of the telescope 10 without requiring
input from a user. Additionally, the telescope 10 may automatically
align itself with virtually any star or other celestial object
specified by the user. As such, the telescope 10 of the present
invention preferably incorporates capabilities shown in
"AUTO-ALIGNMENT TRACKING TELESCOPE MOUNT", U.S. Pat. No. 6,369,942,
hereby incorporated into the present application by reference. The
telescope 10 broadly comprises an optical telescopic tube 12 for
magnifying distant objects, a base 14 for supporting the tube 12, a
cradle 16 for securing the tube 12 to the base 14, a drive
mechanism 18 for moving the tube 12 with respect to the base 14,
and a control unit 20 to control the drive mechanism 18.
[0023] The tube 12 is preferably conventional with manual focus and
zoom functions. Alternatively, the tube 12 may incorporate
automatic focus and/or automatic zoom functions controlled by the
control unit 20. Furthermore, the tube 12 may incorporate other
electrical components, such as those discussed below and associated
with the control unit 20.
[0024] The base 14 is preferably a conventional tri-pod, but may be
a base-plate designed to be mounted to a support surface. The
cradle 16 may comprise a conventional yoke mounting assembly or
another support assembly that allows the tube 12 to move with
respect to the base 14. The drive mechanism 18 preferably comprises
a plurality of stepper motors to govern an altitude angle and an
azimuth angle of the tube 12 with respect to the base 14.
[0025] Referring to FIG. 2, the control unit 20 preferably includes
a database 22 to store astronomical information and a processor 24
to align the tube 12 with a specified star using the drive
mechanism 18. The database 22 preferably includes information about
stars and other celestial objects, such as nebulae. The information
preferably comprises relational location information, such that
each celestial object's location is described in relation to other
celestial bodies. Alternatively, the location information may
include an orbital path for each celestial object with respect to
some reference point, such as the earth, the moon, or the sun. The
information preferably also includes details relating to each
celestial object, such as position, size, magnitude, type of
object, and identification information for each object.
[0026] The control unit 20 also preferably includes a vision device
30 to electronically sense bright stars and a motion sensor 32 to
sense motion of the tube 12 of the telescope 10. The vision device
30 is preferably securely aligned with the tube 12 and may be
secured to the tube 12 or the cradle 16. In fact, the vision device
30 and the tube 12 preferably share substantially identical fields
of view. However, while the vision device 30 must move with the
tube 12, the vision device 30 may be oriented at an angle to the
tube 12. For example, the vision device 30 may be oriented at up to
ninety degrees with respect to the tube 12. Such a modification may
provide the vision sensor 30 with a less obstructed field of
view.
[0027] In either case, the vision device 30 preferably comprises a
charge-coupled device (CCD) camera, but may comprise some other
optical sensor. The vision device 26 preferably generates a vision
signal representative of an image in the vision device's field of
view. Thus, when the tube 12 and the vision device 30 are aligned
and pointed at a first bright star the vision signal is
representative of the first bright star.
[0028] Similarly, the motion sensor 32 is preferably securely
aligned with the tube 12 and may be secured to the tube 12 or the
cradle 16. The motion sensor 32 preferably comprises two motion
encoders, one encoder to sense changes in an altitude angle and one
encoder to sense changes in an azimuth angle of the tube 12. The
motion sensor 32 preferably generates a motion signal
representative of changes in the altitude and azimuth angles.
Therefore, when the tube 12 is slewed from alignment with the first
bright star to a second bright star, the motion signal is
preferably representative of a measured angle between the first and
second bright stars comprising the altitude and azimuth angles
between the first and second bright stars.
[0029] It is important to note that, as used here, the first bright
star does not relate to any specific unique star. The first bright
star only implies that the first bright star is actually sensed
first, upon initialization. As such, the first bright star may
actually be a different star each time the telescope 10 is
initialized. In addition, the first bright star may actually be a
planet or another object that is brighter than surrounding space.
The same principal applies to other bright stars sensed by the
telescope 10.
[0030] The processor 24 uses measured angles, such as that
described above, to calculate the orientation of the telescope 10.
To this end, referring to FIG. 3, the database 22 preferably
contains a matrix of central angles between all known stars. For
example, a first known star has a first central angle with respect
to a second known star, a second central angle with respect to a
third known star, and a third central angle with respect to a
fourth known star. In addition, the second known star also has a
fifth central angle with respect to the third known star, a sixth
central angle with respect to the fourth known star, and so on.
Specifically, for n bright stars, there are preferably
(n.sup.2-n)/2 central angles stored in the matrix. Alternatively,
the matrix may store vertex angles between the known stars. For
efficiency, the angles stored in the matrix are preferably limited
to those having a magnitude greater than two degrees.
[0031] It should be obvious that, since the goal of the present
invention is to determine the orientation of the telescope 10, the
processor 24 is expected to determine which known star corresponds
to the first bright star. Additionally, if the measured angle
between the first and second bright stars exactly and uniquely
matches one of the central angles in the database 22, the processor
24 still must determine which bright star corresponds to which
known star.
[0032] In order to accomplish this, the processor 24 preferably
compares several measured angles with the central angles stored in
the matrix of the database 22. When the processor 24 finds
sufficient matches between the measured angles and the central
angles, with sufficient certainty as will be discussed in greater
detail below, then the processor 24 has effectively identified the
bright stars using the bright stars' relationship to one another.
Once the bright stars are identified, the processor 24 can use the
location information of the bright stars to determine the
orientation of the telescope 10.
[0033] For example, a set measured angles between several bright
stars is compared to the central angles in the matrix. Any measured
angles that nearly match the central angels result in a non-zero
objective function score, which will be discussed in greater detail
below, and are used to determine the orientation of the telescope
10.
[0034] For amateur astronomy purposes, we can assume that the stars
are fixed, with respect to each other and the earth. This
assumption greatly simplifies the matrix, allowing the matrix to
store fixed values for the central angles, as shown in FIG. 3.
However, for more advanced purposes, the matrix may be date
dependant. For example, the matrix may comprise relational
functions using the date as a variable, thereby compensating for
relative movement between the stars, the planets, and the earth.
The telescope 10 may, include a real time clock, receive the date
from the user, or determine the date from positions of the bright
stars or planets.
[0035] The processor 24 automatically compensates for relative
movement of objects used as bright stars, even if the matrix does
not account for relative movement. For example, it can be assumed
that there will be some degree of error between the measured angles
and the central angles stored in the database 22. Thus, as the
processor 24 attempts to match the measured angles to the central
angles, the processor 24 assigns an objective function score to
each potential match. As discussed above, any measured angles that
nearly match the central angles result in the non-zero objective
function score. For instance, if the measured angle exactly matches
one of the central angles, then the objective function score for
that match is one. Alternatively, if the measured angle varies from
a closest central angle by one or more degrees, then the objective
function score for that match is zero and that match is effectively
ignored. For matches with errors between zero and one degrees, the
objective function score for those matches varies linearly between
one and zero. In this manner, each central angle in the matrix is
preferably compared with the each measured angle to determine the
objective function score for each measured angle. Then, the
objective function score may be determined for the set of measured
angles. Accuracy may be further refined by multiplying the
objective function score for each measured angle by the objective
function score for the set of measured angles. Such refinement
emphasizes close matches, while highlighting questionable
matches.
[0036] Planets are often very bright, and therefore may be sensed
as the bright stars. However, the planets typically have much more
relative movement, with respect to the earth, than do most stars.
Thus, when planets are used as bright stars, the matrix preferably
compensates for this relative movement and is date dependent.
Alternatively, the planets may simply be ignored when determining
the location and orientation. For example, measured angles
involving planets are not likely to sufficiently match any of the
central angles in the matrix, if the matrix is not date dependent.
Thus, measured angles involving planets are likely to vary by more
than one degree from the central angles, resulting in the objective
function score for any potential match being zero and those matches
being ignored by the processor 24. This is especially apparent when
one realizes that the processor 24 is comparing the measured angles
between several bright stars.
[0037] The control unit 20 also preferably includes a handheld
remote control 34 that includes a display and a plurality of
buttons allowing the user to interact with the telescope 10. The
remote control 34 preferably communicates with the control unit 20
over a wired connection, but may communicate over a wireless
connection.
[0038] While the present invention has been described above, it is
understood that substitutions can be made. For example, depending
on the quality of the vision device 30, the tube 12 may not be
required. In this case, the user may view the display or another
screen which displays the image from the vision device 30.
Alternatively, the user may align the tube 12 with the bright
stars, thereby minimizing the need for the vision device 30 and the
drive mechanism 18. The telescope 10 may not even require the tube
12 or the vision device 30 to actually move, in order to determine
the orientation of the telescope 10. For example, the vision device
30 may simply take a wide-angle snap-shot of the sky and sense
several bright stars from the snap-shot. In this case, the measured
angles may be inferred by spacing of bright stars in the snap-shot.
Additionally, the drive mechanism 18 may use other types of motors
and may include gears and other components commonly found in
typical drive mechanisms. Furthermore, the database 22 may only
include information about selected celestial bodies, such as
constellations. These and other minor modifications are within the
scope of the present invention.
[0039] In use, the user initializes the telescope 10 by turning on
the telescope 10, pressing one of the buttons on the remote control
34, or simply supplying power. Upon initialization, the processor
24 directs the drive mechanism 18 to scan they sky until the vision
device 30 senses the first bright star.
[0040] The processor 24 preferably senses the first bright star by
analyzing the vision signal. For example, the processor 24 analyzes
the vision signal to find spots in the sky that are significantly
brighter than other light emitting or reflecting bodies. These
bright spots are assumed to be and used as bright stars. For
example, the vision device 30 may provide a wide-angle view of the
sky, from which the processor 24 may sense several bright stars. In
this case, the processor selects one of the bright stars as the
first bright star.
[0041] Alternatively, the drive mechanism 18 may scan the sky by
varying the altitude angle, the azimuth angle, or both. For
example, the drive mechanism 18 may use one of a plurality of
predefined search methods, or a random search method, to sense the
bright stars. One predefined search method comprises pivoting the
tube 12 through 360 degrees of azimuth angle, incrementing the
altitude angle slightly, and then repeating this process. The
random search method preferably comprises changing the altitude
azimuth angles substantially randomly until the first bright star
is sensed.
[0042] In either case, once the vision device 30 has sensed the
first bright star, the processor 24 fine tunes the drive mechanism
18 to substantially center the first bright star within the vision
device's 30 field of view. Once the processor 24 centers the first
bright star within the vision device's 30 field of view, the
processor 24 initializes the motion signal. Then, the processor 24
directs the drive mechanism 18 to once again scan the sky in search
of the second bright star. Once the vision device 30 has found the
second bright star, the processor 24 fine tunes the drive mechanism
18 to substantially center the second bright star in the vision
device's 30 field of view and temporarily stores the measured angle
copied from the motion signal. This process is preferably repeated
for several bright stars until the measured angles between the
bright stars provide a unique solution, from which the orientation
may be determined. While it may be possible to determine the unique
solution with as few as two bright stars, it is anticipated that
more bright stars and several measured angles will typically be
required. In fact, the telescope preferably senses four bright
stars and uses six measured angles between the four bright stars to
determine the orientation of the telescope 10.
[0043] Once the orientation of the telescope 10 is known, the
processor 24 may then find virtually any star or other celestial
object specified by the user. For example, the user preferably
identifies the specified star using the remote control 34, by
selecting the specified star from a list or entering the specified
star's name. The processor 24 searches the database 22 to find
location information for the specified star. The processor 24 then
instructs the drive mechanism 18 to align the tube 12 with the
specified star. The processor 24 may use the vision signal to fine
tune the drive mechanism 18 in order to substantially center the
specified star within the tube's 12 field of view.
[0044] The flow charts of FIGS. 4-5 show the functionality and
operation of a preferred implementation of the present invention in
more detail. In this regard, some of the blocks of the flow charts
may represent a module segment or portion of code of a program of
the present invention which comprises one or more executable
instructions for implementing the specified logical function or
functions. In some alternative implementations, the functions noted
in the various blocks may occur out of the order depicted. For
example, two blocks shown in succession may in fact be executed
substantially concurrently, or the blocks may sometimes be executed
in the reverse order depending upon the functionality involved.
[0045] Referring to FIG. 4, the user initializes the telescope 10,
as depicted in step 4a. The telescope 10 senses the first bright
star and initializes the motion signal, as depicted in step 4b.
Then, the telescope 10 senses the second bright star and copies the
measured angle from the motion signal, as depicted in step 4c.
Then, the telescope 10 senses another bright star and copies
another measured angle from the motion signal, as depicted in step
4d. When the processor 24 has at least two measured angles, the
processor 24 compares the measured angles with the central angles
in the matrix of the database 22 using the objective function
score, as depicted in step 4e. If the processor 24 does not find
the unique solution, the telescope 10 repeats steps 4d-e. If the
processor 24 finds the unique solution, then the processor 24 has
identified the bright stars and may determine the orientation of
the telescope 10 using the information stored in the database 22,
as depicted in step 4f.
[0046] Referring to FIG. 5, once the orientation of the telescope
10 is known, the user may enter the specified star using the remote
control 34, as depicted in step 5a. The processor 24 retrieves
location information for the specified star from the database 22,
as depicted in step 5b. Then, the processor 24 instructs the drive
mechanism 18 to align the tube 12 with the specified star, as
depicted in step 5c. The processor 24 may fine tune the drive
mechanism 18 to substantially center the specified star within the
tube's 12 field of view using the vision device 30, as depicted in
step 5d. At this point, the user may view the specified star
through the tube 12.
* * * * *