Telescope Alignment Method Using a Modified Stochastic Parallel Gradient Descent Algorithm

• DOI: 10.3390/photonics11110993
• Publication Date: 2024-10-22T08:10:14Z
• Authors: Min Li; Xin Liu; Junbo Zhang; Hao Xian
• Keywords: Adam SPGD algorithm; multi-field alignment; wavefront sensorless method; Applied optics. Photonics; telescope alignment; high precision; TA1501-1820

To satisfy the demands of high image quality and resolutions, telescope alignment is indispensable. In this paper, a wavefront sensorless method based on a modified stochastic parallel gradient descent algorithm (SPGD) called the adaptive moment estimation SPGD (Adam SPGD) algorithm is proposed. Simulations are carried out using a four-mirror telescope, whose aperture is 6 m and fields of view are Φ2°. Three misalignments are shown as examples. Positions of the secondary mirror and third mirror are employed to compensate aberrations. The results show that merit functions and energy distributions of corrected images match with the designed ones. The mean RMS of residual wavefront errors is smaller than λ/14 (λ = 0.5 μm), indicating that the misalignments are well compensated. The results verify the effectiveness of our method.