TY - JOUR
T1 - A 20 m wide-field diffraction-limited telescope
T2 - 20 m, wide field UVOIR telescope
AU - Eads, Ryker W.
AU - Angel, J. Roger P.
N1 - Funding Information:
Data accessibility. This article does not contain any additional data. Authors’ contributions. R.W.E. developed the optical design presented in this paper. J.R.P.A. conceived and designed the study and drafted the manuscript. Both authors read and approved the manuscript. Competing interests. We declare we have no competing interests. Funding. Both authors are funded by the University of Arizona.
Publisher Copyright:
© 2020 The Authors.
PY - 2021/1/11
Y1 - 2021/1/11
N2 - A 20 m space telescope is described with an unvignetted 1° field of view- A hundred times larger in area than fields of existing space telescopes. Its diffraction-limited images are a hundred times sharper than from wide-field ground-based telescopes and extend over much if not all the field, 40 arcmin diameter at 500 nm wavelength, for example. The optical system yielding a 1°, 1.36 m diameter image at f/3.9 has relatively small central obscuration, 9% by area on axis, and is fully baffled. Several carousel-mounted instruments can each access directly the full image. The initial instrument complement includes a 400 gigapixel silicon imager with 2 µm pixels (0.005 arcsec), and a 60 gigapixel HgCdTe imager with 5 µm pixels (0.012 arcsec). A multi-object spectrograph with 10 000 fibres will allow spectroscopy with 0.02 arcsec resolution. Direct imaging and spectroscopy of exoplanets can take advantage of the un-aberrated, on-axis image (5 nm RMS wavefront error). While this telescope could be built for operation in free space, a site accessible to a human outpost at the Moon's south pole would be advantageous, for assembly and repairs. The lunar site would allow also for the installation of new instruments to keep up with evolving scientific priorities and advancing technology. Cooling to less than 100E K would be achieved with a surrounding cylindrical thermal shield. This article is part of a discussion meeting issue 'Astronomy from the Moon: The next decades'.
AB - A 20 m space telescope is described with an unvignetted 1° field of view- A hundred times larger in area than fields of existing space telescopes. Its diffraction-limited images are a hundred times sharper than from wide-field ground-based telescopes and extend over much if not all the field, 40 arcmin diameter at 500 nm wavelength, for example. The optical system yielding a 1°, 1.36 m diameter image at f/3.9 has relatively small central obscuration, 9% by area on axis, and is fully baffled. Several carousel-mounted instruments can each access directly the full image. The initial instrument complement includes a 400 gigapixel silicon imager with 2 µm pixels (0.005 arcsec), and a 60 gigapixel HgCdTe imager with 5 µm pixels (0.012 arcsec). A multi-object spectrograph with 10 000 fibres will allow spectroscopy with 0.02 arcsec resolution. Direct imaging and spectroscopy of exoplanets can take advantage of the un-aberrated, on-axis image (5 nm RMS wavefront error). While this telescope could be built for operation in free space, a site accessible to a human outpost at the Moon's south pole would be advantageous, for assembly and repairs. The lunar site would allow also for the installation of new instruments to keep up with evolving scientific priorities and advancing technology. Cooling to less than 100E K would be achieved with a surrounding cylindrical thermal shield. This article is part of a discussion meeting issue 'Astronomy from the Moon: The next decades'.
KW - UVOIR
KW - diffraction-limited
KW - four-mirror
KW - moon-based
KW - space telescope
KW - wide field
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U2 - 10.1098/rsta.2020.0141rsta20200141
DO - 10.1098/rsta.2020.0141rsta20200141
M3 - Article
C2 - 33222639
AN - SCOPUS:85096630599
VL - 379
JO - Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
JF - Philosophical transactions. Series A, Mathematical, physical, and engineering sciences
SN - 0962-8428
IS - 2188
M1 - 20200141
ER -