Advances in astronomy and astrophysics are frequently driven by observations which are technologically limited by the sensitivity of the observing system. Since the beginning of the era of telescopic observation, there has been a drive for ever more sensitive and capable systems. In the modern era, these observatories can be located both on the ground or in space. These kinds of pioneering systems must be significantly more sensitive or capable than the previous generation. As each successor system becomes larger, more sensitive, more complex than its predecessor it also usually becomes more expensive and riskier to develop. Therefore, advancement of the field is ever more dependent on optimal use of financial, scheduling, and human resources. Such optimum development, design, manufacture, and operation of these kinds of systems begins with using relevant lessons learned and avoiding previous pitfalls and errors. Many of the lessons are in the minds of the developers and users and not usually written down. In the rare cases where they are documented, these lessons are scattered throughout the literature. This special section is calling for papers for lessons learned from past, present, and future ground- and space-based, electro-optical and gravitational wave-based observatories. The aim is to create a resource to be used by the astronomical community as it plans the next great generation of observatories.

Examples of the areas of interest for this special section are:

• Early mission studies
• Mission and observatory concept development
• Siting-geographical location for Earth-based systems, orbits for space-based
• Public and community engagement
• Diversity, equity, and inclusion
• Technology development
• Systems architecture development
• Manufacturing readiness
• Descope planning
• Management
• Integrated modeling
• System design
• Requirement flow down
• Identifying and managing reserves; technical performance, cost, schedule
• Risk management
• Manufacture
• Interfaces
• System assembly, integration, and test
• Verification and validation
• Calibration
• Operations including interface to observers
• Observation planning and scheduling
• Maintainability, servicing, and logistics
• Disposal and decommissioning
• Teaming
• Other topics (please contact the guest editors)

To submit a manuscript for consideration in the special section, please prepare the manuscript according to the journal guidelines and submit the paper via the online submission system. Once the special section is opened online, each paper will be published as soon as the copyedited and typeset proofs are approved by the author. A cover letter indicating that the submission is intended for this special section should be included with the paper. Manuscripts published in the Proceedings of SPIE are welcome for submission to this special section after proper revision to meet the standards of a journal publication. Regular submissions will be peer-reviewed in accordance with the journal's established policies and procedures.