Abstract

We describe an off-axis design for a 6.5-m astronomical telescope optimized for low scattered light and low emissivity. This is part of a new concept for an instrument that we call the New Planetary Telescope. We show how the geometric optical performance can equal that of an on-axis conventional telescope while the diffractive performance fundamentally surpasses conventional telescopes because of the absence of pupil obstruction. The decentered concept also allows wide-field and versatile instrumentation configurations that are not possible with more-conventional designs.

© 2000 Optical Society of America

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  1. J. R. Kuhn, S. L. Hawley, “Some astronomical performance advantages of off-axis telescopes,” Publ. Astron. Soc. Pac. 111, 601–620 (1999).
    [CrossRef]
  2. J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).
  3. G. Moretto, J. R. Kuhn, “Off-axis systems for 4-m-class telescopes,” Appl. Opt. 37, 3539–3546 (1998).
    [CrossRef]
  4. M. Paul, “Systemes Correcteurs pour Reflecteurs Astronomique,” Rev. Opt. Theor. Instrum. 15(5) , 169–202 (1935).
  5. D. J. Schroeder, Astronomical Optics (Academic, San Diego, Calif., 1987), Chap. 4, p. 55.
  6. M. Iye, K. Kodiara, “Primary mirror support system for the SUBARU telescope,” in Advanced Technology Optical Telescopes V, L. M. Stepp, ed., Proc. SPIE2199, 762–772 (1994).
    [CrossRef]
  7. J. Lubliner, J. Nelson, “Stressed mirror polishing. 1: Technique for producing nonaxisymmetric mirrors,” Appl. Opt. 19, 2332–2340 (1980).
    [CrossRef] [PubMed]

1999 (1)

J. R. Kuhn, S. L. Hawley, “Some astronomical performance advantages of off-axis telescopes,” Publ. Astron. Soc. Pac. 111, 601–620 (1999).
[CrossRef]

1998 (1)

1980 (1)

1935 (1)

M. Paul, “Systemes Correcteurs pour Reflecteurs Astronomique,” Rev. Opt. Theor. Instrum. 15(5) , 169–202 (1935).

Coulter, R.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Ftaclas, C.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Graves, B.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Hawley, S. L.

J. R. Kuhn, S. L. Hawley, “Some astronomical performance advantages of off-axis telescopes,” Publ. Astron. Soc. Pac. 111, 601–620 (1999).
[CrossRef]

Hull, C.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Iye, M.

M. Iye, K. Kodiara, “Primary mirror support system for the SUBARU telescope,” in Advanced Technology Optical Telescopes V, L. M. Stepp, ed., Proc. SPIE2199, 762–772 (1994).
[CrossRef]

Jewitt, D.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Joseph, R.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Kodiara, K.

M. Iye, K. Kodiara, “Primary mirror support system for the SUBARU telescope,” in Advanced Technology Optical Telescopes V, L. M. Stepp, ed., Proc. SPIE2199, 762–772 (1994).
[CrossRef]

Kuhn, J. R.

J. R. Kuhn, S. L. Hawley, “Some astronomical performance advantages of off-axis telescopes,” Publ. Astron. Soc. Pac. 111, 601–620 (1999).
[CrossRef]

G. Moretto, J. R. Kuhn, “Off-axis systems for 4-m-class telescopes,” Appl. Opt. 37, 3539–3546 (1998).
[CrossRef]

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Lubliner, J.

Mickey, D.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Moretto, G.

G. Moretto, J. R. Kuhn, “Off-axis systems for 4-m-class telescopes,” Appl. Opt. 37, 3539–3546 (1998).
[CrossRef]

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Neill, D.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Nelson, J.

Northcott, M.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Owen, T.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Paul, M.

M. Paul, “Systemes Correcteurs pour Reflecteurs Astronomique,” Rev. Opt. Theor. Instrum. 15(5) , 169–202 (1935).

Roddier, C.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Roddier, F.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Schroeder, D. J.

D. J. Schroeder, Astronomical Optics (Academic, San Diego, Calif., 1987), Chap. 4, p. 55.

Siegmund, W.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Tokunaga, A.

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

Appl. Opt. (2)

Publ. Astron. Soc. Pac. (1)

J. R. Kuhn, S. L. Hawley, “Some astronomical performance advantages of off-axis telescopes,” Publ. Astron. Soc. Pac. 111, 601–620 (1999).
[CrossRef]

Rev. Opt. Theor. Instrum. (1)

M. Paul, “Systemes Correcteurs pour Reflecteurs Astronomique,” Rev. Opt. Theor. Instrum. 15(5) , 169–202 (1935).

Other (3)

D. J. Schroeder, Astronomical Optics (Academic, San Diego, Calif., 1987), Chap. 4, p. 55.

M. Iye, K. Kodiara, “Primary mirror support system for the SUBARU telescope,” in Advanced Technology Optical Telescopes V, L. M. Stepp, ed., Proc. SPIE2199, 762–772 (1994).
[CrossRef]

J. R. Kuhn, A. Tokunaga, R. Joseph, R. Coulter, C. Ftaclas, B. Graves, C. Hull, D. Jewitt, D. Mickey, G. Moretto, D. Neill, M. Northcott, C. Roddier, F. Roddier, W. Siegmund, T. Owen, A New Planetary Telescope (Institute for Astronomy, University of Hawaii, Manoa, Hawaii, 1999).

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Figures (14)

Fig. 1
Fig. 1

Representative bright star image obtained with a conventional 4-m aperture obscured astronomical telescope (Cerro Tobolo Interamerican Observatory Blanco 4 m). Part of the sky is hidden from our point of view by scattered light. The display range shows 3 orders of magnitude and is logarithmic.

Fig. 2
Fig. 2

Scattered-light PSF contributions for a conventional 6.5-m telescope at (A) 1 µm and (B) 4 µm. The solid curve shows the unobscured (NPT) aperture (edge) diffraction. The dotted curve shows the bidirectional reflectance distribution function (BRDF) from mirror roughness scattering assuming a mirror as smooth as the Hubble Space Telescope primary. The dashed curve shows the BRDF from a 2-cm-wide secondary mirror support spider and the dash–dot curve shows the atmospheric BRDF for an atmosphere characterized by a 15-cm Fried parameter.

Fig. 3
Fig. 3

Narrow-field baseline optical mode for the NPT. M1V is the vertex of the primary parent mirror. This configuration does not have circular symmetry but preserves bilateral symmetry.

Fig. 4
Fig. 4

Wide-field baseline optical mode for the NPT with (A) a 6% obscured design and (B) a fully unobstructued design. M1V is the vertex of the primary parent mirror. These configurations do not have circular symmetry but preserve bilateral symmetry.

Fig. 5
Fig. 5

NPT narrow-field mode. Optical performance (OP) shows the parent mirror (M1) vertex. OA is the parent M1 optical axis. Note that the primary mirror M1 and the secondary M2 are not tilted mirrors but are a decentered piece of the concentric Gregorian system. The left panel shows details of the prime focus, secondary mirror, and focal plane.

Fig. 6
Fig. 6

Narrow-field-mode geometric performance constrained by a flat FOV. (A) The PSF computed on the edge of a 2 arc min × 2 arc min FOV. (B) EED for spots on axis and on the edge of a 2 arc min × 2 arc min FOV where the shadow region shows d80. The performance inside this FOV is presented in Fig. 8.

Fig. 7
Fig. 7

Narrow-field mode with a curved FOV. (A) The PSF computed on the edge of a 2 arc min × 2 arc min FOV. (B) EED for spots on axis and on the edge of a 2 arc min × 2 arc min FOV. The shadow region shows d80.

Fig. 8
Fig. 8

Narrow-field-mode optical performance inside of 2 arc min × 2 arc min and extended without optimization to a 4 arc min × 4 arc min FOV. The two curves are for the design with flat FOV constraint and a curved (R FOV = 632.9 mm) FOV. DL, diffraction limit.

Fig. 9
Fig. 9

Schematic of the 14-m f/1 wide-field-mode NPT telescope. Bottom: Optical layout for the simplest wide-field-mode layout. Top: The obscuration (OBS) produced by the M2 over M1 (M2/M1), M3 over M1 (M3/M1), and focal plane (FP) over M3 (FP/MP). M1-POA is the primary parent mirror optical axis. EPD, entrance pupil diameter.

Fig. 10
Fig. 10

NPT wide-field mode from the 14-m f/1 parent primary mirror optical performance. (A) The PSF computed on the edge of a 2-deg FOV. (B) EED on axis and on the edge of a 2-deg FOV. EE, encircled energy.

Fig. 11
Fig. 11

Schematic of the 15-m f/1 wide-field-mode NPT telescope.

Fig. 12
Fig. 12

NPT wide-field mode from the 15-m f/1 parent primary mirror optical performance. (A) The PSF computed on the edge of a 2-deg FOV. (B) EED on axis and on the edge of a 2-deg FOV.

Fig. 13
Fig. 13

Relative position of the wide-field and the narrow-field modes. Both are from a 14-m f/1 parent mirror operating modes of the NPT. The M2-GREG/INST is a typical instrument volume used by the cryogenic IR secondary.

Fig. 14
Fig. 14

Relative position of the wide-field and the narrow-field modes. Both are from a 15-m f/1 parent mirror operating modes of the NPT. In this case in which the primary mirror is tilted at 3.8 deg, when changing the operation modes, we need to move only in and out the secondary mirror (M2 WIDE) to the wide-field mode. The M2-GREG/INST volume, M3 wide, and focal plane (FP) are fixed.

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