Related Experiment Video
Updated: Jun 16, 2026
05:46
Correction of Presbyopia by Monocular Bi-Aspheric Ablation Profile
Published on: September 20, 2024
Third order aberrations in cassegrain-type telescopes and coma correction in servo-stabilized images
Applied Optics
|January 23, 2010
Summary
Servo-control of telescope secondary mirrors corrects pointing errors but can cause aberrations. This study presents a configuration that eliminates coma in space telescope images by using aspheric mirror corrections, detailing residual aberrations.
Area of Science:
- Optical engineering
- Space optics
- Telescope aberrations
Background:
- Space vehicle telescopes require precise pointing.
- Servo-control of secondary mirrors can correct pointing errors.
- Mirror asphericity introduces aberrations into stabilized images.
Purpose of the Study:
- To present a telescope configuration that corrects pointing errors without introducing coma.
- To calculate required aspheric mirror corrections.
- To determine residual aberrations and summarize aberration constants for Cassegrain telescopes.
Main Methods:
- Servo-control system analysis for secondary mirror adjustment.
- Aspheric mirror design and optical modeling.
- Aberration calculation using third-order optics.
Main Results:
- A specific configuration eliminates coma for centered images of off-axis points.
- Calculations provide required aspheric corrections for mirrors.
- Residual aberrations are quantified for the proposed configuration.
Conclusions:
- Servo-control with aspheric mirror corrections can achieve coma-free imaging in space telescopes.
- The presented configuration offers a method to mitigate aberrations caused by pointing correction.
- Understanding aberration constants is crucial for designing advanced Cassegrain telescopes.
Related Concept Videos
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:26Phase Contrast and Differential Interference Contrast Microscopy
Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
01:26Influence of Earth's Curvature and Atmospheric Refraction on Leveling
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
01:15Distance Corrections
To achieve precise distance measurements, especially in surveying and construction, certain corrections must be applied to account for potential sources of error like the standardization errors, temperature variations, and slope adjustments.Standardization error emerges when measurement equipment undergoes changes, such as wear, repairs, or weather impacts. To address this, surveyors compare the equipment’s readings to a standard. This process identifies any deviation that might lead to...