James Webb Space Telescope: Preference Observatory

Impression texture: The Rho-Oviucci molecular cloud in the constellation Ophiuchus is the closest star-forming region to Earth at a distance of 390 light-years. Here are sun-like stars with oceanic disks of gas and dust in which planets form. The image was captured by the Webb Infrared Space Telescope at wavelengths ranging from 1.8 to 4.7 micrometers. The observatory is considered the most powerful of its kind, and since mid-2022 it has been exploring space from small planets in the solar system to distant galaxies and the first stars.
© NASA, ESA, CSA, STScI, K. Pontoppidan, A. Pagan

A small problem: The Webb telescope can determine the quality of its primary mirror itself using wavefront measurements. It’s almost as excellent as it is on Earth – despite shocks during takeoff and cooling in space of about 250 degrees Celsius. Only in C3 at the bottom right does the wavefront deviate slightly from the optimum (white dot). This is the result of a small meteorite impact. The three narrow, bar-shaped regions containing no measurement data are, so to speak, shadows of the secondary mirror carriers.
©bdw Illustration: Karl Marx; Source: J. Rigby et al., Publications of the Astronomical Society of the Pacific, Volume 135, Article 048001 (2023)

It looks worse than it is: the effects of a small meteorite hitting the mirror portion of the Webb telescope. The image does not show holes, but rather wavefront measurements. The black bar is not a crack, but the shadow of a supporting pillar.
© NASA

Infrared splendor: Details of the Orion Nebula in the constellation of the same name, 1,350 light-years away. Here, high-energy ultraviolet radiation from the Trapezium star cluster (top left) interacts with dense molecular clouds and slowly melts them. This affects a wide range of chemical reactions. This can be observed, for example, in a young star system called d203–506. It contains a protoplanetary disk around the red dwarf star (inset). There, astronomers led by Olivier Bernier of the Center National de la Recherche Scientifique (CNRS) in Toulouse, France, detected a methyl cation (CH3+) in space for the first time. It plays an important role in the formation of more complex carbon molecules. The Webb Telescope captured the image at infrared wavelengths between 1.6 and 4.8 micrometers.
©ESA/Webb, NASA, CSA, M. Zamani, PDRs4ALL ERS Team