Abstract

A new differential variable-star photometry system has been designed, constructed, and tested at the Rothney Astrophysical Observatory of the University of Calgary. The system uses a single telescope, photometer, and detector and consists of gated pulse-counting electronics synchronized to a chopped secondary mirror. The mirror is driven to four positions, permitting rapid alternate detection of a variable star, comparison star, and two sky-background regions. Within certain constraints the system is insensitive to the effects of transparency, sky-brightness, and detector-sensitivity variations occurring on time scales longer than the system’s duty cycles. The system has proved effective under as much as three magnitudes of cloud and attendant sky-brightness variation.

© 1982 Optical Society of America

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References

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  1. J. S. Hall, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 41.
  2. D. J. Taylor, Publ. Astron. Soc. Pac. 92, 108 (1980).
    [CrossRef]
  3. H. K. Myrabo, Astron. Astrophys. 84, 297 (1980).
  4. B. Warner, R. E. Nather, Sky and Telescope 43, 82 (1972).
  5. E. H. Geyer, M. Hoffmann, Astron. Astrophys. 38, 359 (1975).
  6. A. D. Grauer, H. E. Bond, Publ. Astron. Soc. Pac. 93, 388 (1981).
    [CrossRef]
  7. T. B. McCord, Appl. Opt. 7, 475 (1968).
    [CrossRef] [PubMed]
  8. Th. Walraven, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 114.
  9. T. A. Clark, E. F. Milone, Bull. Am. Astron. Soc. 11, 32 (1979).
  10. T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
    [CrossRef]
  11. R. H. Hardie, in Astronomical Techniques, W. A. Hiltner, Ed. (U. Chicago, 1962), p. 187.
  12. E. F. Milone, in Non-Periodic Phenomena in Variable Stars, L. Detre, Ed. (Academic Press, Budapest, 1969), p. 457.

1981 (1)

A. D. Grauer, H. E. Bond, Publ. Astron. Soc. Pac. 93, 388 (1981).
[CrossRef]

1980 (2)

D. J. Taylor, Publ. Astron. Soc. Pac. 92, 108 (1980).
[CrossRef]

H. K. Myrabo, Astron. Astrophys. 84, 297 (1980).

1979 (1)

T. A. Clark, E. F. Milone, Bull. Am. Astron. Soc. 11, 32 (1979).

1977 (1)

T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
[CrossRef]

1975 (1)

E. H. Geyer, M. Hoffmann, Astron. Astrophys. 38, 359 (1975).

1972 (1)

B. Warner, R. E. Nather, Sky and Telescope 43, 82 (1972).

1968 (1)

Bond, H. E.

A. D. Grauer, H. E. Bond, Publ. Astron. Soc. Pac. 93, 388 (1981).
[CrossRef]

Chia, T. T.

T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
[CrossRef]

Clark, T. A.

T. A. Clark, E. F. Milone, Bull. Am. Astron. Soc. 11, 32 (1979).

Geyer, E. H.

E. H. Geyer, M. Hoffmann, Astron. Astrophys. 38, 359 (1975).

Grauer, A. D.

A. D. Grauer, H. E. Bond, Publ. Astron. Soc. Pac. 93, 388 (1981).
[CrossRef]

Hall, J. S.

J. S. Hall, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 41.

Hardie, R. H.

R. H. Hardie, in Astronomical Techniques, W. A. Hiltner, Ed. (U. Chicago, 1962), p. 187.

Hoffmann, M.

E. H. Geyer, M. Hoffmann, Astron. Astrophys. 38, 359 (1975).

McCord, T. B.

Milone, E. F.

T. A. Clark, E. F. Milone, Bull. Am. Astron. Soc. 11, 32 (1979).

T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
[CrossRef]

E. F. Milone, in Non-Periodic Phenomena in Variable Stars, L. Detre, Ed. (Academic Press, Budapest, 1969), p. 457.

Myrabo, H. K.

H. K. Myrabo, Astron. Astrophys. 84, 297 (1980).

Nather, R. E.

B. Warner, R. E. Nather, Sky and Telescope 43, 82 (1972).

Robb, R. M.

T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
[CrossRef]

Taylor, D. J.

D. J. Taylor, Publ. Astron. Soc. Pac. 92, 108 (1980).
[CrossRef]

Walraven, Th.

Th. Walraven, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 114.

Warner, B.

B. Warner, R. E. Nather, Sky and Telescope 43, 82 (1972).

Appl. Opt. (1)

Astron. Astrophys. (2)

E. H. Geyer, M. Hoffmann, Astron. Astrophys. 38, 359 (1975).

H. K. Myrabo, Astron. Astrophys. 84, 297 (1980).

Astrophys. Space Sci. (1)

T. T. Chia, E. F. Milone, R. M. Robb, Astrophys. Space Sci. 48, 3 (1977).
[CrossRef]

Bull. Am. Astron. Soc. (1)

T. A. Clark, E. F. Milone, Bull. Am. Astron. Soc. 11, 32 (1979).

Publ. Astron. Soc. Pac. (2)

D. J. Taylor, Publ. Astron. Soc. Pac. 92, 108 (1980).
[CrossRef]

A. D. Grauer, H. E. Bond, Publ. Astron. Soc. Pac. 93, 388 (1981).
[CrossRef]

Sky and Telescope (1)

B. Warner, R. E. Nather, Sky and Telescope 43, 82 (1972).

Other (4)

J. S. Hall, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 41.

Th. Walraven, in Astronomical Photoelectric Photometry, F. B. Wood, Ed. (American Association for the Advancement of Science, Washington, D.C., 1953), p. 114.

R. H. Hardie, in Astronomical Techniques, W. A. Hiltner, Ed. (U. Chicago, 1962), p. 187.

E. F. Milone, in Non-Periodic Phenomena in Variable Stars, L. Detre, Ed. (Academic Press, Budapest, 1969), p. 457.

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Figures (5)

Fig. 1
Fig. 1

Major components and subsystems of the RADS.

Fig. 2
Fig. 2

Flowchart of the data acquisition cycle. Although control is shared, start and stop commands at the keyboards initiate a cycle and cause a halt after output, respectively. No data are lost during readout, and the process may continue unattended at the discretion of the observer.

Fig. 3
Fig. 3

Pulse-counted observations at the star BD + 34° 4213 in an instrumental system similar to V of the UBV system. Filled squares represent uncorrected magnitudes in one channel; filled circles represent the ratio of sky-background corrected light of the star seen in channel A to that of the same star seen in channel C, converted to magnitudes. The abscissa is in numbers of mean-solar minutes.

Fig. 4
Fig. 4

Observations of the stars HR352 and HR356 separated by 18 min of arc on the plane of the sky. This separation is near our chopping limit. In this case, the filled circles represent the magnitude difference of sky-corrected light from each star.

Fig. 5
Fig. 5

Observations of the closer pair HR1764 and HR1765 separated by 4 min of arc. Legend as in Figs. 3 and 4.

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