Curved Secondary Mirror Support for Telescope Vibration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing telescope designs with a tripod structure for secondary mirror support suffer from significant deformations that affect the relative angular position of primary and secondary mirrors, leading to instability and precision issues, especially under external vibrations like those from helicopter rotors.
Innovation Solution
A secondary mirror support with three feet connected to the primary mirror outside its central zone, an outer ring, and inclined legs with non-zero curvature, reducing the amplitude of deformations and increasing the frequency of natural modes of vibration to prevent detrimental vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a tripod structure is used to support the secondary mirror, then the device complexity is reduced, but the stability of the mirror angular position deteriorates due to deformations
Solution Approach 1:
The patent applies curvature to the legs of the support structure, transforming them from straight elements to curved elements with specific radii of curvature. This curvature is designed to compensate for deformations under gravitational load, maintaining the angular position stability of the mirrors while preserving the tripod structure's simplicity.
Solution Approach 2:
The patent modifies the geometric parameters of the support structure, specifically the curvature radius of the legs and the angles they form with the optical axis. By optimizing these parameters, the structure achieves reduced deformations and improved stability without increasing complexity.
2Manufacturing precision
If the support structure is made rigid to reduce deformations, then the manufacturing precision increases, but the dynamic deformations under vibration increase due to higher natural frequencies
Solution Approach 1:
The curved geometry of the legs provides structural rigidity to reduce manufacturing and assembly tolerances, while the specific curvature radii are chosen to optimize the natural frequencies of the structure, balancing rigidity with vibration resistance.
Solution Approach 2:
The patent designs the support structure with specific geometric parameters that raise the natural frequencies of the system above the dominant vibration frequencies of the helicopter rotor, thereby minimizing resonance and dynamic deformations during operation.
3Ease of manufacture
If the legs are made straight and simple, then the ease of manufacture increases, but the amplitude of deformations increases under gravitational and vibrational loads
Solution Approach 1:
The legs are manufactured with a specific curved geometry defined by radii of curvature, which provides enhanced structural strength and deformation resistance compared to straight legs, while remaining manufacturable using standard fabrication processes.
Solution Approach 2:
The patent specifies precise geometric parameters for the curved legs, including curvature radii and angular orientations, which optimize the strength-to-manufacturing-complexity ratio, allowing the legs to resist deformations effectively while remaining practical to manufacture.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a support (3) for rigidly maintaining a secondary mirror of a telescope forward of a central zone of a primary mirror of the telescope, said support comprising an outer ring (30) intended to be connected to the secondary mirror and at least three legs (35a) which each connect the outer ring to a foot (34a) of the support. Each leg has a non-zero curvature that is oriented such that a concave segment of the leg faces away from the central zone of the primary mirror when the telescope is assembled. Such a curvature reduces variations in the inclination of the primary and secondary mirrors, which inclination variations are produced by dynamic deformation of the support and in opposite directions for the two mirrors.