The construction of the next generation of extremely large telescopes is underway: the Giant Magellan Telescope (GMT), ESO’s Extremely Large Telescope (ELT), and the Thirty Meter Telescope (TMT) are becoming reality and involve contributing teams from all over the world. Scaling telescope constructions to these dimensions introduces some challenges that lots of researchers and engineers are working on. This special section of JATIS is intended to provide a centralized reference on the ELTs' development. We would like to encourage collaborative papers as much as possible. So we are encouraging combined papers to show a comparison between at least two of the next big telescopes. Topics of discussion include but are not limited to: 

• Metrology and alignment. 
• Phasing of mirrors. For example. phasing test beds. 
• Telescope and subsystem performance modeling and measurement.
  • Vibration
    • How do you manage the vibration? 
    • Also linked to utilities: coolant, glycol, compressor, etc.
  • Thermal, heat dissipation 
  • Modeling of dome seeing 
  • Adaptive Optics for ELTs: How much do we model? What is the expected performance?
• AIV papers (technical commissioning).
• Operation plan: similitudes and differences.
  • Science commissioning 
  • Transition
• Preventive maintenance to keep the observatory to specifications from the beginning. Issues with complexity.
• SE processes and tools.
  • Requirements management
  • SE performances: Technical Performance Matrix indicators (TPM)

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.

The starshade has emerged as a viable technology for the observation and characterization of exoplanets. Since the inception of the starshade, the field has developed rapidly, and the advances are widely spread in the literature and hard to find. This special section of JATIS is intended to provide a centralized contemporary reference for this exciting and capable technology.

The topics of interest for this special section are as follows:

• Error budgeting
• Starshade-based missions (at all scales)
• Performance modeling
• Other science enabled by starshades, specifically non-exoplanet missions
• Data processing, the reduction of starshade images to science data
• Optical modeling
• Optics of starshades
• Testing and verification of starshades
• Mission planning
• Image postprocessing
• Instrument design for use with a starshade
• Petal edge and face scattering
• Scaling rules
• Testing and verification
• Design (apodization) optimization of the starshade
• Formation sensing, maintenance and operations

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. 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.

The guest editors are also seeking for comprehensive review papers in the areas listed above. Authors interested in submitting a review paper to this special section should contact the guest editors with a brief proposal of the paper.