active optics analog-to-digital converter angular diameter angular resolution aperture synthesis apparent magnitude astronomical object astronomical seeing boeing computer deformable mirror digital-to-analog converter fourier optics guide star hubble space telescope image resolution image stabilization laser laser guide star lenslet light lucky imaging luminosity mesosphere microcontroller mirror mount nasa operational amplifier optical coherence tomography optics orbit pid controller pixel retina satellite shack-hartmann sodium solar system speckle imaging star stepper motor swedish solar telescope technology telescope thermosphere turbulence very large telescope wavefront wavefront sensor