Modern Advances in Optical, Millimeter and Submillimeter Astronomy

Dear Colleagues,

For multi-band astronomical observations, especially in optical bands, atmospheric optical turbulence can affect the imaging quality and resolution of ground-based telescopes. The atmosphere as an inhomogeneous medium will cause a fluctuation in the atmospheric refractive index due to the fluctuations in meteorological elements such as temperature, wind, etc., forming optical turbulence along the path of propagation of light. The fluctuation in atmospheric refractive index caused by turbulence leads to the wavefront distortion of light, destroys the coherence of light, causes the blur of optical image, reduces the imaging resolution of the target, and affects the tracking and positioning accuracies, which confine large aperture telescope for astronomical and space observations. Moreover, for laser communication, the irradiance scintillations introduced by atmospheric turbulence will cause the jitter of the received power and the deterioration of the bit error rate of laser communication. The speckle effect of laser caused by phase distortion will cause the decrease in tracking accuracy and the fiber coupling efficiency of PAT (pointing, capturing, tracking) unit. The atmospheric polarization disturbance will decrease the mixing efficiency of coherent laser communication system, and the deflection effect of atmosphere will affect the alignment accuracy of the PAT unit and other parameters. All of these can seriously affect the transmission and communication of laser signals, and become the technical bottleneck restricting the development and application of high-speed satellite–ground laser communication.

With the development of astronomical high-resolution methods and techniques, especially adaptive optics which can correct the effect of atmospheric turbulence in real time, the image quality and resolution of telescopes are greatly improved. The real-time mastery of the parameters of atmospheric optical turbulence become of key importance for the adaptive optical (AO) telescopes. The design of the adaptive optical systems requires the stratified information of atmospheric optical turbulence parameters from near the ground to an altitude of 30 kilometers, with higher vertical resolution and response time. Also, the Earth’s atmosphere strongly influences radio astronomy observations at the millimeter and submillimeter wave levels. As in the optical range, the study of the current state of the astro-climate in the millimeter and submillimeter range is of great interest in the world. We invite colleagues to present their work based on many years of efforts to find sites with good atmospheric transparency at the millimeter and submillimeter wave levels, developing methods and tools to measure and evaluate atmospheric opacity.

This Special Issue aims at presenting the latest results in optical, millimeter and submillimeter astronomy. In particular, issues and results of astro-climatic studies are discussed as applied to projects of large optical and millimeter telescopes. The latest achievements in the field of atmospheric modeling, the use of modern mesoscale models in order to improve the resolution and accuracy of estimating the content of water vapor, optical turbulence, atmospheric transparency and cloudiness are considered. We welcome broad, visionary contributions of short research reports as well as a collection of reviews of accomplishments. We are excited to invite researchers to submit their contributions to this Special Issue. Relevant topics include but are not limited to the following:

• Atmospheric optics;
• Optical turbulence;
• Influence of solar activity;
• Millimeter astronomy;
• Astro-climate;
• Adaptive optics;
• Laser communication;
• Optical neural network.

Dr. Xuan Qian
Dr. Artem Shikhovtsev
Dr. Yongqiang Yao
Dr. Pavel Kovadlo
Guest Editors

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• atmospheric optics
• turbulence
• adaptive optics
• site testing
• astro-climate
• astronomical sensors
• optical astronomy
• millimeter astronomy
• influence of solar activity
• laser communication