4:15 PM - 4:30 PM
[PCG18-16] Removal of stray light generated by bandpass filters in visible light optics and focusing performance of optical systems
In asteroid and lunar exploration missions, high-resolution observation of the surface in visible light is important to study the surface environment of the target celestial body.
In general visible light optical systems, bandpass filters are often used to selectively transmit only specific wavelengths, but stray light due to reflection occurs between the lens and filter, or between the filter and detector. Stray light is the unnecessary scattering of light inside the optical system, and the quality of the image is degraded when stray light enters the detector.
As a solution to this problem, a method of using two bandpass filters with each tilted in different directions has been proposed to shift stray light components out of the optical path without degrading the focusing performance of the optical system (Enya et al. 2021).
In this study, we added the installation mechanism of two bandpass filters to the prototype telescope, which has the similar performance as that of the optical navigation camera system (ONC) onboard the Hayabusa2 spacecraft, and actually introduced a parallel light source to eliminate stray light and evaluate the focusing performance of the optical system.
In this prototype, since the parameters such as the angle of the filter, the angle of incidence of the light, and the placement of the filter can be changed , the relationship between the parameters and the position and brightness of stray light was derived by analyzing CCD images obtained under various conditions, and the optimal solution for stray light removal was determined.
In addition, we evaluated the focusing performance of the optical system when a bandpass filter was installed under the introduced optimum conditions.
In general visible light optical systems, bandpass filters are often used to selectively transmit only specific wavelengths, but stray light due to reflection occurs between the lens and filter, or between the filter and detector. Stray light is the unnecessary scattering of light inside the optical system, and the quality of the image is degraded when stray light enters the detector.
As a solution to this problem, a method of using two bandpass filters with each tilted in different directions has been proposed to shift stray light components out of the optical path without degrading the focusing performance of the optical system (Enya et al. 2021).
In this study, we added the installation mechanism of two bandpass filters to the prototype telescope, which has the similar performance as that of the optical navigation camera system (ONC) onboard the Hayabusa2 spacecraft, and actually introduced a parallel light source to eliminate stray light and evaluate the focusing performance of the optical system.
In this prototype, since the parameters such as the angle of the filter, the angle of incidence of the light, and the placement of the filter can be changed , the relationship between the parameters and the position and brightness of stray light was derived by analyzing CCD images obtained under various conditions, and the optimal solution for stray light removal was determined.
In addition, we evaluated the focusing performance of the optical system when a bandpass filter was installed under the introduced optimum conditions.