Optical: systems and elements – Compound lens system – Telescope
Reexamination Certificate
2000-05-08
2001-11-27
Nguyen, Thong (Department: 2872)
Optical: systems and elements
Compound lens system
Telescope
C359S366000, C359S857000
Reexamination Certificate
active
06323996
ABSTRACT:
BACKGROUND
In a typical prior art application, a Newtonian reflector telescope includes a tube having an open outer end and a closed inner end. A concave primary mirror is carried against or near the closed inner end, and reflects a cone-shaped light pattern back toward the open end. A secondary mirror is supported within the tube near the open end, and is oriented at a 45 degree angle. The secondary mirror reflects the light generally perpendicular to the tube, and into an eyepiece carried on the outside of the tube. A typical eyepiece has a rack-and-pinion adjustment, and resembles a microscope.
The primary mirror has a focal length, i.e. a length between the primary mirror and the point or plane of focus, e.g. at the eyepiece. The focal ratio is the focal length divided by the diameter of the primary mirror.
A number of problems are associated with such reflector telescopes. A first problem is of a commercial nature, in that the tube and primary mirror of a first manufacturer are often incompatible with the focuser and eyepiece of a second manufacturer. Given a tube and primary mirror having a particular focal length and focal ratio, an eyepiece and associated focusing device (or camera or similar optical device) must be selected which is adapted for bringing into focus a fixed range of distances; e.g. 1000′ to infinity. It is a characteristic of the market place that where the tube and primary mirror is made by a given manufacturer, the recommended eyepiece and associated focusing device will be so adapted. However, where a second manufacturer's devices (eyepiece, camera, etc.) are used with the tube and primary mirror of a first manufacturer, it is often the case that the device is unusable, due to incompatibility with focal characteristics of the primary mirror. As a result, it is often the case that a tube and primary mirror made by a first manufacturer must be fitted with a focuser and eyepiece made by that manufacturer. In this manner, many manufacturers tend to prevent the use of other manufacturers' equipment with their equipment.
A second problem results from the use of reflector telescopes. Depending on the focusing conditions, a focuser tube may extend from the eyepiece into the main tube of the telescope to an excessive degree. This results in occlusion of the view, in that some light entering the main tube is prevented from contacting the primary mirror because it is blocked by the focusing tube. With known reflector telescopes, this condition will result when the eyepiece is focused to one extreme.
A third problem results from the use of reflector telescopes. Since most reflector telescopes are designed for astronomical use, they are only able to focus at the most distant terrestrial objects. The reason for this inadequacy is that, given the focal length, the eyepiece and associated focuser are constructed for focusing at astronomically distant objects. Nevertheless, reflector telescopes are not inherently unable to be used for viewing extremely close objects. However, in the prior art, no successful strategy for focusing a single telescope from as little as 10 feet to infinite distance has been developed.
For the foregoing reasons, there is a need for a reflector telescope that will allow operation of any given telescope tube assembly and primary mirror with any given focuser and eyepiece assembly. The reflector telescope must operate with the focuser tube substantially out of the main telescope tube, while still allowing the eyepiece to be focused. Additionally, the reflector telescope should be adapted for sharp focus over a substantially greater range of distance than conventional reflector telescopes, and in particular should be adapted for focus on extremely close objects.
SUMMARY
The present invention is directed to an apparatus that satisfies the above needs. A reflector telescope with an adjustable secondary mirror assembly can be adjusted to allow operation of any given telescope tube assembly and primary mirror with any given focuser and eyepiece assembly used in the secondary mirror assembly. The distance between the at least one secondary mirror assemblies and the primary mirror assembly is adjustable, thereby allowing the focuser tube of each secondary mirror assembly to be kept substantially out of the telescope tube assembly, while still allowing the eyepiece associated with the secondary mirror assembly to be focused. Additionally, movement of the secondary mirror assemblies of the instant reflector telescope results in sharp focus over a substantially greater range of distance than conventional reflector telescopes, and in particular allows focus on extremely close objects.
The reflector telescope with an adjustable secondary mirror assembly of the present invention provides some or all of the following structures.
(A) A telescope tube assembly includes a plurality of frame tube or rod elements defining a passage between them.
(B) A primary mirror assembly, carried at an inner end of the telescope tube assembly, includes a primary mirror carried within a cylindrical tube enclosure. In a preferred embodiment, the primary mirror defines first and second reflective surfaces. A primary mirror mover permits movement of the primary mirror between a first position wherein the first reflective surface is moved into an optical path defined within the telescope tube assembly to a second position wherein the second reflective surface is moved into the optical path defined within the telescope tube assembly.
(C) A first, or inner, secondary mirror assembly includes a cylindrical tube enclosure having an outside surface carrying a plurality of cylindrical bearings, each cylindrical bearing sliding on an associated frame tube element of the telescope tube assembly. A secondary mirror is carried within the cylindrical passage of the telescope tube assembly by a secondary mirror support carried by a cylindrical tube enclosure. The cylindrical bearings allow the first secondary mirror assembly to be moved along the telescope tube assembly in a manner that allows selection of the distance between the primary mirror and the first secondary mirror.
(D) Optionally, a second, or outer, secondary mirror assembly includes substantially the same elements as the first secondary mirror assembly, and slides on the plurality of frame tube or rod elements of the telescope tube assembly between the first secondary mirror assembly and an outer end of the telescope tube assembly.
It is therefore a primary advantage of the present invention to provide a novel reflector telescope having adjustment means for varying the distance between the secondary mirror and the primary mirror, thereby allowing the use of a variety of different pieces of optical equipment associated with the secondary mirror, by adjusting the distance between the primary and secondary mirror to suit the piece of optical equipment selected.
Another advantage of the present invention is to provide a novel reflector telescope having adjustment means for varying the distance between the secondary mirror and the primary mirror, thereby allowing the secondary mirror and associated optical equipment (e.g. the eyepiece) to be adjusted to a location (typically closer to the outer end of the telescope frame assembly) that is not the standard location for astronomical viewing with the optical equipment, but which allows sharp focus on objects much closer to the telescope that would otherwise be possible.
Another advantage of the present invention is to provide a novel reflector telescope having adjustment means for varying the distance between the secondary mirror and the primary mirror in a manner which cooperates synergistically with a primary mirror having more than one reflective surface, particularly where each reflective surface has a different focal length.
A still further advantage of the present invention is to provide a novel reflector telescope having adjustment means for varying the distance between the secondary mirror and the primary mirror, thereby allowing the secondary mirror and assoc
Black Lowe & Graham
Nguyen Thong
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