Abstract

We have developed a multichannel spectrophotometric detector system using a 1024 element self-scanned silicon photodiode array, which is now in routine operation with the high-dispersion coudé spectrograph of the University of Texas McDonald Observatory 2.7-m telescope. We discuss operational considerations in the use of such arrays for high precision and low light level spectrophotometry. A detailed description of the system is presented. Performance of the detector as measured in the laboratory and on astronomical program objects is described, and it is shown that these arrays are highly effective detectors for high dispersion astronomical spectroscopy.

© 1978 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
    [CrossRef]
  2. L. A. Marschall, L. M. Hobbs, Astrophys. J. 173, 43 (1972).
    [CrossRef]
  3. T. H. Morgan, R. C. Baldwin, A. E. Potter, in Instrumentation in Astronomy II, Proceedings of Tucson, Arizona Conference (Society of Photo-Optical Instrumentation Engineers, 1974), p. 147.
    [CrossRef]
  4. R. G. Tull, in Proceedings of ESO/CERN Conference on Auxiliary Instrumentation for Large Telescopes, S. Laustsen, A. Reiz, Eds. (ESO/CERN, Geneva, 1972), p. 259.
  5. R. G. Tull, J. P. Choisser, E. H. Snow, Appl. Opt. 14, 1182 (1975).
    [CrossRef] [PubMed]
  6. R. G. Tull, in Digest of Topical Meeting on Imaging in Astronomy (Optical Society of America, Washington, D.C., 1975), paper FB9.
  7. R. G. Tull, in Proceedings IAU Colloquium 40, M. Duchesne, G. L. Lelievre, Eds. (Paris-Meudon Obs., France, 1976), paper 23-1.
  8. R. G. Tull, R. E. Nather, in Astronomical Observations with Television-Type Sensors, J. W. Glaspey, G. A. H. Walker, Eds. (U. British Columbia, Vancouver, 1973), p. 171.
  9. D. Dravins, Astrophys. Space Sci. Lib. 54, 97 (1975).
    [CrossRef]
  10. H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).
  11. R. C. Smithson, Solar Phys. 40, 241 (1975).
    [CrossRef]
  12. V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
    [CrossRef]
  13. B. Campbell, Ph.D. Thesis, U. Toronto (1976).
  14. W. C. Livingston, J. Harvey, J. Slaughter, D. Trumbo, Appl. Opt. 15, 40 (1976).
    [CrossRef] [PubMed]
  15. W. C. Livingston, in Ref. 7, paper 22-1.
  16. J. C. Geary, in Ref. 7, paper 28-1.
  17. G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.
  18. G. P. Weckler, IEEE J. Solid-State Circuits SC-2, 65 (1967).
    [CrossRef]
  19. R. R. Buss, S. C. Tanaka, G. P. Weckler, in Solid State Imaging, P. G. Jespers, F. Van de Wiele, M. H. White, Eds., NATO Advanced Study Institute Series, Noordhoff, Leyden (1976).
  20. R. C. Jones, Adv. Electron. Electron Phys. 11, 87 (1959).
    [CrossRef]
  21. R. S. Neiswander, G. S. Plews, Appl. Opt. 14, 2720 (1975).
    [CrossRef] [PubMed]
  22. E. H. Snow, Reticon Corp. private communication (1977).
  23. A. M. Title, Solar Phys. 35, 233 (1974).
    [CrossRef]
  24. A. T. Young, Rev. Sci. Instrum. 37, 1472 (1966).
    [CrossRef]
  25. P. Kelton, G. W. van Citters, in Ref. 7, paper 36-1.
  26. R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.
  27. D. J. Mullan, Astrophys. J. 192, 149 (1974).
    [CrossRef]
  28. S. P. Worden, Publ. Astron. Soc. Pac. 86, 595 (1974).
    [CrossRef]
  29. S. S. Vogt, Bull. Am. Astron. Soc. 8, 535 (1976).
  30. C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).
  31. G. Wallerstein, Publ. Astron. Soc. Pac. 70, 479 (1958).
    [CrossRef]
  32. D. S. Evans, B. W. Bopp, Observatory 94, 80 (1974).

1976 (3)

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

W. C. Livingston, J. Harvey, J. Slaughter, D. Trumbo, Appl. Opt. 15, 40 (1976).
[CrossRef] [PubMed]

S. S. Vogt, Bull. Am. Astron. Soc. 8, 535 (1976).

1975 (5)

R. S. Neiswander, G. S. Plews, Appl. Opt. 14, 2720 (1975).
[CrossRef] [PubMed]

R. G. Tull, J. P. Choisser, E. H. Snow, Appl. Opt. 14, 1182 (1975).
[CrossRef] [PubMed]

D. Dravins, Astrophys. Space Sci. Lib. 54, 97 (1975).
[CrossRef]

H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).

R. C. Smithson, Solar Phys. 40, 241 (1975).
[CrossRef]

1974 (4)

A. M. Title, Solar Phys. 35, 233 (1974).
[CrossRef]

D. J. Mullan, Astrophys. J. 192, 149 (1974).
[CrossRef]

S. P. Worden, Publ. Astron. Soc. Pac. 86, 595 (1974).
[CrossRef]

D. S. Evans, B. W. Bopp, Observatory 94, 80 (1974).

1972 (1)

L. A. Marschall, L. M. Hobbs, Astrophys. J. 173, 43 (1972).
[CrossRef]

1971 (1)

R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
[CrossRef]

1967 (1)

G. P. Weckler, IEEE J. Solid-State Circuits SC-2, 65 (1967).
[CrossRef]

1966 (1)

A. T. Young, Rev. Sci. Instrum. 37, 1472 (1966).
[CrossRef]

1959 (1)

R. C. Jones, Adv. Electron. Electron Phys. 11, 87 (1959).
[CrossRef]

1958 (1)

G. Wallerstein, Publ. Astron. Soc. Pac. 70, 479 (1958).
[CrossRef]

Baldwin, R. C.

T. H. Morgan, R. C. Baldwin, A. E. Potter, in Instrumentation in Astronomy II, Proceedings of Tucson, Arizona Conference (Society of Photo-Optical Instrumentation Engineers, 1974), p. 147.
[CrossRef]

Beer, R.

R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
[CrossRef]

Bopp, B. W.

D. S. Evans, B. W. Bopp, Observatory 94, 80 (1974).

Buchholz, V.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Buchholz, V. L.

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

Buss, R. R.

R. R. Buss, S. C. Tanaka, G. P. Weckler, in Solid State Imaging, P. G. Jespers, F. Van de Wiele, M. H. White, Eds., NATO Advanced Study Institute Series, Noordhoff, Leyden (1976).

Campbell, B.

B. Campbell, Ph.D. Thesis, U. Toronto (1976).

Choisser, J. P.

Condal, A.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Dravins, D.

D. Dravins, Astrophys. Space Sci. Lib. 54, 97 (1975).
[CrossRef]

Evans, D. S.

D. S. Evans, B. W. Bopp, Observatory 94, 80 (1974).

Fahlman, G. G.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Ford, H. C.

H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).

Geary, J. C.

J. C. Geary, in Ref. 7, paper 28-1.

Glaspey, J.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Glaspey, T. W.

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

Harvey, J.

Hobbs, L. M.

L. A. Marschall, L. M. Hobbs, Astrophys. J. 173, 43 (1972).
[CrossRef]

Isherwood, B. C.

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

Jenner, D. C.

H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).

Jones, R. C.

R. C. Jones, Adv. Electron. Electron Phys. 11, 87 (1959).
[CrossRef]

Kelton, P.

P. Kelton, G. W. van Citters, in Ref. 7, paper 36-1.

Lambert, D. L.

C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).

Lane-Wright, D.

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Livingston, W. C.

Marschall, L. A.

L. A. Marschall, L. M. Hobbs, Astrophys. J. 173, 43 (1972).
[CrossRef]

Mochnacki, S.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Morgan, T. H.

T. H. Morgan, R. C. Baldwin, A. E. Potter, in Instrumentation in Astronomy II, Proceedings of Tucson, Arizona Conference (Society of Photo-Optical Instrumentation Engineers, 1974), p. 147.
[CrossRef]

Mullan, D. J.

D. J. Mullan, Astrophys. J. 192, 149 (1974).
[CrossRef]

Nather, R. E.

R. G. Tull, R. E. Nather, in Astronomical Observations with Television-Type Sensors, J. W. Glaspey, G. A. H. Walker, Eds. (U. British Columbia, Vancouver, 1973), p. 171.

Neiswander, R. S.

Norton, R. H.

R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
[CrossRef]

Peterson, R. C.

C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).

Plews, G. S.

Potter, A. E.

T. H. Morgan, R. C. Baldwin, A. E. Potter, in Instrumentation in Astronomy II, Proceedings of Tucson, Arizona Conference (Society of Photo-Optical Instrumentation Engineers, 1974), p. 147.
[CrossRef]

Seaman, C. H.

R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
[CrossRef]

Slaughter, J.

Smithson, R. C.

R. C. Smithson, Solar Phys. 40, 241 (1975).
[CrossRef]

Sneden, C.

C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).

Snell, R.

R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.

Snow, E. H.

R. G. Tull, J. P. Choisser, E. H. Snow, Appl. Opt. 14, 1182 (1975).
[CrossRef] [PubMed]

E. H. Snow, Reticon Corp. private communication (1977).

Tanaka, S. C.

R. R. Buss, S. C. Tanaka, G. P. Weckler, in Solid State Imaging, P. G. Jespers, F. Van de Wiele, M. H. White, Eds., NATO Advanced Study Institute Series, Noordhoff, Leyden (1976).

Title, A. M.

A. M. Title, Solar Phys. 35, 233 (1974).
[CrossRef]

Tomkin, J.

C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).

Trumbo, D.

Tull, R. G.

R. G. Tull, J. P. Choisser, E. H. Snow, Appl. Opt. 14, 1182 (1975).
[CrossRef] [PubMed]

R. G. Tull, in Proceedings of ESO/CERN Conference on Auxiliary Instrumentation for Large Telescopes, S. Laustsen, A. Reiz, Eds. (ESO/CERN, Geneva, 1972), p. 259.

R. G. Tull, in Digest of Topical Meeting on Imaging in Astronomy (Optical Society of America, Washington, D.C., 1975), paper FB9.

R. G. Tull, in Proceedings IAU Colloquium 40, M. Duchesne, G. L. Lelievre, Eds. (Paris-Meudon Obs., France, 1976), paper 23-1.

R. G. Tull, R. E. Nather, in Astronomical Observations with Television-Type Sensors, J. W. Glaspey, G. A. H. Walker, Eds. (U. British Columbia, Vancouver, 1973), p. 171.

R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.

van Citters, G. W.

P. Kelton, G. W. van Citters, in Ref. 7, paper 36-1.

vanden Bout, P.

R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.

Vogt, S. S.

S. S. Vogt, Bull. Am. Astron. Soc. 8, 535 (1976).

R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.

Walker, G. A. H.

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

Wallerstein, G.

G. Wallerstein, Publ. Astron. Soc. Pac. 70, 479 (1958).
[CrossRef]

Weckler, G. P.

G. P. Weckler, IEEE J. Solid-State Circuits SC-2, 65 (1967).
[CrossRef]

R. R. Buss, S. C. Tanaka, G. P. Weckler, in Solid State Imaging, P. G. Jespers, F. Van de Wiele, M. H. White, Eds., NATO Advanced Study Institute Series, Noordhoff, Leyden (1976).

Wood, B.

H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).

Worden, S. P.

S. P. Worden, Publ. Astron. Soc. Pac. 86, 595 (1974).
[CrossRef]

Young, A. T.

A. T. Young, Rev. Sci. Instrum. 37, 1472 (1966).
[CrossRef]

Adv. Electron. Electron Phys. (2)

V. L. Buchholz, G. A. H. Walker, T. W. Glaspey, B. C. Isherwood, D. Lane-Wright, Adv. Electron. Electron Phys. 40B, 879 (1976).
[CrossRef]

R. C. Jones, Adv. Electron. Electron Phys. 11, 87 (1959).
[CrossRef]

Appl. Opt. (3)

Astrophys. J. (2)

L. A. Marschall, L. M. Hobbs, Astrophys. J. 173, 43 (1972).
[CrossRef]

D. J. Mullan, Astrophys. J. 192, 149 (1974).
[CrossRef]

Astrophys. Space Sci. Lib. (1)

D. Dravins, Astrophys. Space Sci. Lib. 54, 97 (1975).
[CrossRef]

Bull. Am. Astron. Soc. (2)

H. C. Ford, D. C. Jenner, B. Wood, Bull. Am. Astron. Soc. 7, 293 (1975).

S. S. Vogt, Bull. Am. Astron. Soc. 8, 535 (1976).

IEEE J. Solid-State Circuits (1)

G. P. Weckler, IEEE J. Solid-State Circuits SC-2, 65 (1967).
[CrossRef]

Observatory (1)

D. S. Evans, B. W. Bopp, Observatory 94, 80 (1974).

Publ. Astron. Soc. Pac. (2)

G. Wallerstein, Publ. Astron. Soc. Pac. 70, 479 (1958).
[CrossRef]

S. P. Worden, Publ. Astron. Soc. Pac. 86, 595 (1974).
[CrossRef]

Rev. Sci. Instrum. (2)

A. T. Young, Rev. Sci. Instrum. 37, 1472 (1966).
[CrossRef]

R. Beer, R. H. Norton, C. H. Seaman, Rev. Sci. Instrum. 42, 1393 (1971).
[CrossRef]

Solar Phys. (2)

A. M. Title, Solar Phys. 35, 233 (1974).
[CrossRef]

R. C. Smithson, Solar Phys. 40, 241 (1975).
[CrossRef]

Other (14)

T. H. Morgan, R. C. Baldwin, A. E. Potter, in Instrumentation in Astronomy II, Proceedings of Tucson, Arizona Conference (Society of Photo-Optical Instrumentation Engineers, 1974), p. 147.
[CrossRef]

R. G. Tull, in Proceedings of ESO/CERN Conference on Auxiliary Instrumentation for Large Telescopes, S. Laustsen, A. Reiz, Eds. (ESO/CERN, Geneva, 1972), p. 259.

R. G. Tull, in Digest of Topical Meeting on Imaging in Astronomy (Optical Society of America, Washington, D.C., 1975), paper FB9.

R. G. Tull, in Proceedings IAU Colloquium 40, M. Duchesne, G. L. Lelievre, Eds. (Paris-Meudon Obs., France, 1976), paper 23-1.

R. G. Tull, R. E. Nather, in Astronomical Observations with Television-Type Sensors, J. W. Glaspey, G. A. H. Walker, Eds. (U. British Columbia, Vancouver, 1973), p. 171.

R. R. Buss, S. C. Tanaka, G. P. Weckler, in Solid State Imaging, P. G. Jespers, F. Van de Wiele, M. H. White, Eds., NATO Advanced Study Institute Series, Noordhoff, Leyden (1976).

B. Campbell, Ph.D. Thesis, U. Toronto (1976).

W. C. Livingston, in Ref. 7, paper 22-1.

J. C. Geary, in Ref. 7, paper 28-1.

G. A. H. Walker, V. Buchholz, G. G. Fahlman, J. Glaspey, D. Lane-Wright, S. Mochnacki, A. Condal, in Ref. 7, paper 24-1.

E. H. Snow, Reticon Corp. private communication (1977).

P. Kelton, G. W. van Citters, in Ref. 7, paper 36-1.

R. Snell, R. G. Tull, P. vanden Bout, S. S. Vogt, in CNO Isotopes in Astrophysics,” Proceedings Special IAU Session, Grenoble, France, 30 August 1976, J. Audouze, Ed. (Reidel, Dordrecht, Holland, 1977), p. 85.

C. Sneden, D. L. Lambert, J. Tomkin, R. C. Peterson, Astrophys. J., in press (1977).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (20)

Fig. 1
Fig. 1

Quantum efficiency of the RL-1024 array and several conventional photocathodes.

Fig. 2
Fig. 2

Schematic of the RL- 1024B diode array showing the on-chip readout circuitry for multiplexing the diodes onto four video lines.

Fig. 3
Fig. 3

Expected signal-to-noise ratio from a Reticon array in direct mode at T = −130°C, as compared with that from a Digicon with S-20 photocathode. Readout noise of σ = 800 electrons has been assumed.

Fig. 4
Fig. 4

Detective quantum efficiency of a direct mode Reticon at −130°C compared with an S-20 Digicon. The solid point was derived from the 60-sec integration (lower spectrum) in Fig. 15 and the open point from the 5-sec integration (middle spectrum) in Fig. 15.

Fig. 5
Fig. 5

Output signal of a selected diode in the array (in the absence of light) as a function of time elapsed after a quick burst of five successive readouts (lasting 125 msec). This effect is a result of self-heating of the array by power dissipation during readout.

Fig. 6
Fig. 6

Measured wavelength response of the Reticon array relative to that at T = −30°C for various temperatures.

Fig. 7
Fig. 7

Optical layout of the coudé spectrograph of the 2.7-m telescope, showing the location of the Reticon and Digicon detectors at the Newtonian focus of the 183-cm spherical camera mirror. This is a view from directly above the spectrograph which is layed out on a horizontal plane.

Fig. 8
Fig. 8

Sectional schematic of the Reticon coldbox housing.

Fig. 9
Fig. 9

Block diagram of the electronic control system.

Fig. 10
Fig. 10

Schematic of the DISH electronics.

Fig. 11
Fig. 11

Waveforms associated with the DISH circuit of Fig. 10.

Fig. 12
Fig. 12

Output signal from the Reticon array vs relative input intensity (at a fixed integration time) as monitored with an RCA C31034A photomultiplier. Open circles represent the first attempt; solid squares represent the second attempt several hours later. The operating temperature was −140°C, and the system noise level is indicated by the horizontal dashed line (800 electrons rms). Each data point was computed from the mean over all 1024 diodes.

Fig. 13
Fig. 13

Pulse height spectrum of the output signal from a selected diode in the array in the presence of dark (zero signal) readouts. The abscissa represents output signal in A/D units plus an arbitrary zero offset. The fitted curve is a normal distribution showing the system noise to be essentially normally distributed with a standard deviation of 750 electrons. One A/D unit equals 1005 electrons.

Fig. 14
Fig. 14

Thermal leakage (dark current) of the diode array vs temperature. The discontinuity at −50°C and gentle upward curvature are probably not real, but due to changes in the cooling system during the 10-month interval over which these data were obtained. The point at T = −140°C represents the mean signal over all 1024 diodes after a 1-h integration on dark.

Fig. 15
Fig. 15

Speed comparison test of the Reticon vs the single channel RCA C31034A scanner at λ8500 Å on the solar spectrum. The upper spectrum is a 30-min observation with the scanner. The middle is a 5-sec Reticon exposure, and the lower spectrum is a 1-min Reticon exposure. The small plot to the left of each is the smoothed power spectrum of the data.

Fig. 16
Fig. 16

Interstellar 7Li absorption features in the spectra of Aur (top) and ζ Per (bottom). The expected position of the 7Li doublet is indicated by solid vertical lines and the 6Li doublet by dashed vertical lines. One-sigma error bars are indicated as obtained from the adjacent 200 channels of continuum.

Fig. 17
Fig. 17

Interstellar 12CH+ and 13CH+ absorption features in ζ Oph. The upper spectrum is a vertically expanded version of the lower spectrum. The expected position of the 13CH+ feature is indicated by a vertical solid line. This observation resulted in a [12CH+/13CH+] ratio of 90 (+35,−20) for the interstellar medium.

Fig. 18
Fig. 18

Zeeman analyzed spectra of three dwarf M stars. Only the right-hand circularly polarized member of each Zeeman pair is shown. The upper spectrum is AU Mic, the middle is BY Dra, and the lower is 61 Cyg B. Note the doubling of absorption lines in BY Dra (double-lined spectroscopic binary). The line near channel 880 in the lower spectrum is λ6173.343 FeI, a particularly sensitive normal Zeeman triplet.

Fig. 19
Fig. 19

Upper spectrum: TiO bandhead near λ8860 Å in α Her. Lower spectrum: 12CN and 13CN lines in HR 6791.

Fig 20
Fig 20

Upper spectrum: KI resonance lines at λ7664 Å and λ7699 Å in the irregular late-type variable VY CMa Middle spectrum: the same region in the spectrum of α Ori. Lower spectrum: the same spectral region but 12 sec of arc West of α Ori, showing the KI lines now in emission, indicative of a very extended gas shell around this supergiant star.

Equations (16)

Equations on this page are rendered with MathJax. Learn more.

DQE = ( S / N ) o 2 / ( S / N ) i 2 ,
( S / N ) Digicon 1 1.15 ( RQE D N p Δ T ) 1 / 2 ,
( S / N ) in = ( N p Δ T ) 1 / 2 ,
DQE Digicon 0.76 RQE D ,
( S / N ) Reticon = RQE R N p Δ T ( RQE R N p Δ T + 2 σ 2 + 2 N L Δ T ) 1 / 2 ,
DQE Reticon RQE R 1 + [ ( 2 σ 2 ) / ( RQE R N p Δ T ) ] .
NEC R = 1 q e ( kT C D ) 1 / 2 ,
NEC A = C υ q e [ 4 kTB ( k o g m ) ] 1 / 2 ,
S A i = ( Q i N p i + N L i ) Δ T A G j + FPS i ,
S B i = G j N L i Δ T B + FPS i , where Δ T B Δ T A .
D i = ( S A i S B i ) = [ Q i N p i Δ T A + N L i ( Δ T A Δ T B ) ] G j .
S i = ( N P i Δ T A ) / ( N C i Δ T C ) ,
NEC A ( rms charges ) = 100 + 2.6 × C υ ( pF ) .
β = ( NEC ) / B ,
speed , Reticon ( 5 - sec exposure ) speed , scanner = 180
speed , Reticon ( 60 - sec exposure ) speed , scanner 970 .

Metrics