Guider with a secondary prism carrier

Abstract

The invention relates to an Off-Axis guider, with a secondary prism carrier (3) with a secondary prism (7), which is adapted to the main body (1), as is the case with the primary prism carrier (2) with a primary prism (5). A camera sensor (9) is adapted to the secondary' prism carrier (3). The guide has a slide rail (12) and a primary prism carrier height adjustment shaft (14), which is adjusted by an adjustment arm (16), as well as a focusing mechanism attached to the secondary prism / mirror carrier (3). The invention achieves optimal light capture, is small in size, easy to install and adjust and achieves microfocusing electronically without the need for manual focusing by the user or his physical presence.

Description

[0001] DESCRIPTION

[0002] GUIDER WITH A SECONDARY PRISM CARRIER

[0003] FIELD OF ART

[0004] The invention relates to the field of physics and more specifically to the field of instruments. More specifically, it relates to the field of optics and more specifically to the field of optical elements, systems and instruments. Even more specifically , it relates to the field of telescopes, optical sights and optical sighting or aiming devices, which have prisms or mirrors. Specifically, it relates to an advanced guider with a secondary prism / mirror carrier, which has an integrated camera, a focusing mechanism and a primary prism / mirror height adjuster.

[0005] BACKGROUND OF THE INVENTION

[0006] The guider with a secondary prism carrier disclosed in the present invention has not been disclosed in the prior art.

[0007] Astrophotography is a type of photography that deals with capturing images of the night sky, including stars, planets, the Moon, galaxies, and other celestial objects. Astrophotographers use specialized equipment, such as special cooled cameras with large sensors, telescopes, and equatorial mounts to capture the beauty of the starry sky.

[0008] Astrophotography also requires special techniques, such as long exposures, tracking, and guiding to collect more light from stars and reduce noise. Astrophotography photographs can depict the sky in ways that are not visible to the naked eye.

[0009] The need to take long exposures to capture faint objects necessitates the use of equatorial mounts, which compensate for the Earth’s rotation and keep the subject stationary in the center of the field.

[0010] However, because object tracking cannot usually have the necessary accuracy, it is necessary to add guiding devices, which in cooperation with a second camera (guide camera) allow to track one or more stars from the field and send corrective movements towards the equatorial mount. There are two basic types of telescope guiding devices: guiding telescopes (guidescopes) and Off-Axis guiders (OAGs). Each type, however, has its own disadvantages.

[0011] Guidescopes are small telescopes mounted on top of the main telescope, connected to a second camera (guide camera). Using software, the movement of the stars in the field to be photographed is observed, in order to send the necessary corrective movements to the equatorial mount.

[0012] However, guidescopes have some disadvantages. The first problem is the differential flexure as guiding requires very small movements, of a few micrometers. It Is therefore extremely difficult to ensure absolute support of the guiding telescope on the main one at this level of accuracy. Even small, imperceptible movements of the guiding telescope relative to the main one degrade the quality of the guiding.

[0013] In addition, guiding telescopes have reduced resolution. For reasons of size, weight and cost, they carry lower quality optics and a shorter focal length than the main telescope. This limits their ability to perceive the motion of stars with the necessary accuracy.

[0014] Unlike guiding telescopes, the Off-Axis guiders (OAGs) are placed between the main camera and the telescope's focuser. They work by deflecting a portion of the light collected by the telescope, using a prism or mirror, and directing it towards a separate, guide camera. The guide camera tracks the movement of the stars and, by means of appropriate software, sends the necessary commands for corrections to the equatorial mount.

[0015] Although Off-Axis guiders have two main advantages over guiding telescopes, as they do not present a differential flexure, since light does not have to pass through two separate telescopes, and they maintain high resolution, since the light they receive comes directly from the main telescope, they still present some drawbacks.

[0016] First, it can be extremely complicated to set them up, even for experienced users. This is because the user must ensure that the path of light to the main camera and to the guide camera is of the same length. The light focusing in each telescope is different, making perfect alignment a challenge. Although in theory Off-Axis guiders (OAGs) are a technically superior option, with increased adjustment capabilities, in practice they present significant limitations, both in their handling and in their configuration. This has the result that achieving the desired result requires delicate manipulations and continuous repetitions, even by experienced users. Their most important disadvantages are summarized below. Initially, users must adjust the Off-Axis guiders before placing them in the astrophotography system. In addition, after first focusing the main telescope, they must manually adjust the height of the guide camera inside the Off-Axis guider support head, in a range and adjustment values that usually vary between 21 and 131 micrometers (pm). This makes it understandable how difficult it is to correctly make this adjustment with the necessary precision, manually. Furthermore, the external dimensions of the guide cameras put on the market are affected by the dimensions of their electronic parts and have a diameter of at least 36mm to 62mm. Therefore, the guide cameras can be placed at a minimum distance and this limits the use and operation of the Off-Axi s guiders in many astrophotography systems.

[0017] Another significant disadvantage is that there are also limitations as far as the dimensions of the prism or mirror are concerned. It cannot be large so that it does not obstruct the light reaching the main camera. These limitations in relation to the distance of the main camera and the size of its sensor create problems of non-uniform and complete illumination of the guiding camera sensor. In addition, the position of the guiding camera in its carrier is usually secured by using side screws. Their uneven pressure on the walls of the guiding camera can cause it to bend and affect its perpendicularity in relation to the optical path, causing eccentricity and other optical aberrations to the stars, which affect the quality of guiding. At the same time, placing the guide camera on the head of the Off-Axis guiders may under certain conditions allow unwanted light to enter the astrophotography system, damaging the astrophotography session.

[0018] Furthermore, most astrophotographers use monochrome cameras, due to their greater sensitivity. To produce colour images, special filters are used, which are added to a filter wheel and alternated during the night, so that the combination of shots gives a colour result. However, the different length of light that each filter allows to reach the main camera also affects its focusing distance. Particularly in telescopes with long focal lengths, this requires the refocusing of the guide camera. This is a prohibitive factor for the correct operation of the Off-Axis guider, especially in remote use observatories, where the physical presence of the user is not possible. Moreover, interrupting astrophotography to refocus the Off-Axis guider often results in a waste of valuable time. Taking into account that most of the above arrangements must be carried out at night, in complete darkness and often in adverse weather conditions, it is understandable how much the degree of difficulty of using these specific solutions increases.

[0019] It is thus an object of the present invention to advantageously address the aforementioned disadvantages and shortcomings of the prior art by proposing a guider with a secondary prism / mirror carrier, which has an integrated camera, a focusing mechanism and a primary prism / mirror height adjuster.

[0020] A further object of the present invention is to provide a guider, where the integration of the camera sensor within the device allows the height of the guide camera to be limited, compared to traditional Off-Axis guiders. A further object of the present invention is to provide a guider with a secondary prism carrier, where the direct contact of the camera sensor with the secondary prism ensures uniform and complete illumination, solving problems of star eccentricity and optical aberrations. At the same time, a closed system is created, where the integration of the camera sensor blocks the entry of unwanted light, improving the quality of guiding. A further object of the invention is to provide a guider with a secondary prism carrier, where the user can adjust the height of the primary prism, without disconnecting the device from the astrophotography sy stem.

[0021] A further object of the invention is to present a guider with a secondary prism carrier, where the device enables automatic corrective focus adjustments when changing filters.

[0022] Another advantage that the invention offers to users is that they can make all the necessary adjustments, via software, without physical presence or intervention in the system. An additional advantage of the present invention is also that the ability to adjust the height of the primary prism ensures optimal light reception, without shading the main camera sensor.

[0023] An additional feature of the guider with a secondary prism / mirror carrier is that it has locking positions for the secondary prism / mirror, camera sensor and focusing mechanism.

[0024] These and other objects, features and advantages of the invention will become apparent in the following detailed description

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will become apparent to those skilled in the art with reference to the accompanying drawings in which it is illustrated in an indicative non-limiting manner.

[0027] Figure I shows in a detailed three-dimensional view the device of the invention and its individual components.

[0028] Figure 2 is a perspective view of the device of the invention, where the rolling guide on the main body, as well as the stepper motor and the camera sensor are visible.

[0029] Figure 3 shows in a three-dimensional view the assembled device of the invention, where the adjustment knob for adjusting the primary prism carrier via the primary prism carrier height adjustment shaft is visible.

[0030] Figure 4 shows the path of light w'hen using an Off-Axis guider.

[0031] DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0032] Referring now to the accompanying drawings, we will describe an indicative mode of operation and adjustment of the guider with a secondary prism / mirror carrier of the invention.

[0033] The guider with a secondary prism / mirror carrier consists of a main body (1), Fig. 1, to which both a primary prism / mirror carrier (2) and a secondary prism / mirror carrier (3) are attached. The primary prism carrier (2) has a locking position (4) for applying a primary prism (5) thereto. Correspondingly, the secondary prism carrier (3) has a corresponding locking position (6) for applying a secondary prism (7) thereto, On the secondary prism carrier (3) there are at least two camera sensor locking and tilt adjustment positions (8), to which the camera sensor (9) fits, Fig. 2, Both the primary prism carrier (2) and the secondary prism carrier (3) have attachment positions (10), (11) respectively, on a slide rail (12), which fits on the main body (1), Furthermore, the primary prism carrier (2) has an attachment position (13) for attaching a primary prism carrier height adjustment shaft (14), Fig. 3, which similarly fits on the main body ( 1). The secondary prism carrier (3) also fits on the same primary prism carrier height adjustment shaft (14) via an attachment position (15), The height adjustment of the primary prism carrier (2) is done via an adjustment arm (16) that locks the primary prism carrier height adjustment shaft (14) in a locking position (17) on the main body (1).

[0034] The secondary prism carrier (3) has an attachment position on the focusing mechanism (18) and may connect to a stepper motor (19), which is remotely controlled like the camera sensor (9), via an integrated circuit (20). In this way, the integrated camera can be focused using software, with high precision, of a few micrometers, but also automatically based on predefined parameters that have been set in the astrophotography software.

[0035] To date, the distance y2, Fig, 4, where an off-axis guider is placed, from the main camera, so that there is the necessary space for the insertion of a filter wheel changes the distance β1 and consequently the height β 2 of the guide camera. The length a depends on the telescope's corrective element and in most telescopes it is 55mm. The length a must always be equal to the sum of β1 and β2 . The combination of camera and filter wheel usually has a su m of 32mm. Υ2 is greater than 32mm and therefore the height of the guide camera β2 has a specific range that it can take which must be less than 23mm. The external dimensions of the guide cameras available on the market are influenced by the dimensions of their electronic parts and have a diameter of at least 36mm to 62mm. Therefore, the guide cameras have a minimum distance β1 where they can be placed and this distance limits the use and operation of Off-Axis guiders in many astrophotography systems.

[0036] The operating principle of the device of the invention is that by using the secondary prism carrier (3) and inserting a secondary prism (7) or even a mirror, the light is deflected a second time and enables a camera sensor (9) to be integrated in parallel with the device. This solves the problem of the guide cameras' size and allows the camera sensor (9) to come closer to the light path. Thus, limiting the guide camera height β2 and therefore the light path, gives greater flexibility in the placement of the Off-Axis guiders on the astrophotography equipment but also in the adjustment of the height yl of the primary prism (2).

[0037] At the same time, by using the camera sensor locking and tilt adjustment positions (8), direct contact of the camera sensor (9) with the secondary prism (3) and its vertical position in the light path are ensured, solving problems of non-uniform and total illumination of the guide camera sensor, the eccentricity of stars and other optical aberrations.

[0038] Furthermore, by integrating the camera sensor (9) within the device, the system becomes closed and the entry of unwanted light is prevented.

[0039] Through the attachment position on the focusing mechanism (18) of the secondary prism carrier (3), the possibility of connection with a stepper motor (19) is given and through the attachment position (11) with the slide rail (12) and the attachment position (15) with the primary prism carrier height adjustment axis (14), and movement of the secondary prism carrier (3) on a vertical axis and microfocusing can be carried out electronically, without the need for manual focusing by the user or his physical presence. Stepper motors of this type have high precision and can, with the use of appropriate software, focus with absolute precision. Corrective focusing when changing filters may also be achieved automatically. Through the secondary prism carrier (3) the user may make all the necessary adjustments using software, whenever and as many times as needed, without the need for his physical presence or intervention on the system.

[0040] At the same time, through the adjustment arm (16), the user can rotate the primary prism carrier height adjustment shaft (14) and change the height of the primary prism carrier (2), and therefore the distance yl of the primary prism (5) from the light path, in order to achieve optimal light reception from the primary prism (5), without causing shadowing on the main camera sensor (21). The adjustment arm (16) in conjunction with the primary prism carrier height adjustment shaft (14) allow the user to do this without having to disconnect the device from the astrophotography system, which has not been possible to date with any Off-Axis guider to make all the necessary adjustments using software, whenever and as many times as necessary, without the need for his physical presence or intervention on the system.

[0041] It should be noted at this point that the description of the invention was made with reference to indicative, and not limited, examples of application. Consequently, any change or modification with regard to the shape, dimensions, morphology, construction and assembly components, provided that they do not constitute a new inventive step and do not contribute to the technical development of what is already known, are considered to be included in the aims and objectives of the present invention.

Claims

CLAIMS1. A guider with a secondary prism carrier, consisting of a main body (1), a primary prism / mirror carrier (2) atached to the main body (1 ), with a locking position (4) for the primary prism (5), characterized in that it carries a secondary prism / mirror carrier (3) attached to the main body (1 ), with a locking position (6) for a secondary prism (7), a camera sensor (9) attached to the secondary prism carrier (3), with at least two locking and tilt adjustment positions (8), a slide rail (12) attached to the main body (1), with attachment positions (10) and ( 11) for the primary prism / mirror (2) and secondary prism / mirror (3) carriers respectively, a primary prism carrier height adjustment shaft (14) attached to the main body (1), with an attachment position (13) on the primary prism / mirror carrier (2) and an attachment position (15) on the secondary prism / mirror carrier (3), an adjustment aim (16) for the primary prism carrier height adjustment shaft ( 14) and a focusing mechanism attached to the secondary prism / mirror carrier (3),2. A guider with a secondary prism carrier, according to claim 1 , characterized in that the focusing mechanism 16 is atached to the secondary prism / mirror carrier (3) via a attachment position (18).

3. A guider with a secondary prism carrier, according to claim I, characterized in that the secondary prism carrier (3) is connected to a stepper motor (19) and an integrated circuit (20) for remote control of the camera sensor (9) and the stepper motor (19).

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