Abstract

A method to sensitivity calibrate Digital Single Lens Reflective (DSLR) cameras is outlined. A low intensity calibrated light source tunable in wavelength is described. 31 monochromatic lines from 4000 to 7000 Å with a bandpass of ~12 Å were used to find the spectral responses for the D70 and the D200 cameras manufactured by Nikon. The source radiance ranged from about 300 to 1.6k R/Å. The cameras were operated in manual mode with 4 seconds exposure time at ISO 1600, which are typical settings required for night time photography of the aurora. For the Nikon D200 camera, the blue, green and red spectral responsivities peak at 4600, 5300 and 5900 Å, respectively. The response was high for the blue colour channel with a clear cut-off at 4100 Å for the UV part of the spectrum. The red channel response indicates low sensitivity above 6600 Å. The D70 shows similar spectral responsivity, except that it peaks in the green colour channel and it is more sensitive to both UV and NIR radiation. Both cameras are capable of detecting night - and dayside auroral at 4 second exposure time. For optimal auroral imaging capability, the green and red spectral responsivities need to be shifted up by about 300 and 400 Å in wavelength.

© 2008 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. N. Partamies, M. Syrjäsuo, and E. Donovan, "Using colour in auroral imaging," Can. J. Phys. 85, 101-109 (2007).
    [CrossRef]
  2. J. W. Chamberlain, Physics of the Aurora and Airglow, (Academic Press, New York and London, 1961).
  3. D. Baker and G. Romick, "The Rayleigh: interpretation of the unit in terms of column emission rate or apparent radiance expressed in SI units," Appl. Opt. 15, 1966 - 1968 (1976).
    [CrossRef] [PubMed]
  4. F. Sigernes, J. M. Holmes, M. Dyrland, D. A. Lorentzen, S. Chernous, T. Svenøe, J. Moen, and C. S. Deehr, "Absolute calibration of optical devices with a small field of view," J. Opt. Technol. 74, 669-674 (2007).
    [CrossRef]
  5. G. W. Chang, and Y. C. Chen, "Spectral responsivity estimator for color vision systems: filter selection and noise effect," Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci. 25, 115 - 126 (2001).
  6. C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
    [CrossRef]
  7. M. H. Rees, Physics and chemistry of the upper atmosphere, (Cambridge University Press, 1989).
    [CrossRef]

2007

2001

G. W. Chang, and Y. C. Chen, "Spectral responsivity estimator for color vision systems: filter selection and noise effect," Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci. 25, 115 - 126 (2001).

1980

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

1976

Baker, D.

Chang, G. W.

G. W. Chang, and Y. C. Chen, "Spectral responsivity estimator for color vision systems: filter selection and noise effect," Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci. 25, 115 - 126 (2001).

Chen, Y. C.

G. W. Chang, and Y. C. Chen, "Spectral responsivity estimator for color vision systems: filter selection and noise effect," Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci. 25, 115 - 126 (2001).

Chernous, S.

Deehr, C. S.

F. Sigernes, J. M. Holmes, M. Dyrland, D. A. Lorentzen, S. Chernous, T. Svenøe, J. Moen, and C. S. Deehr, "Absolute calibration of optical devices with a small field of view," J. Opt. Technol. 74, 669-674 (2007).
[CrossRef]

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Donovan, E.

N. Partamies, M. Syrjäsuo, and E. Donovan, "Using colour in auroral imaging," Can. J. Phys. 85, 101-109 (2007).
[CrossRef]

Duncan, C.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Dyrland, M.

Egeland, A.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Gilmer, J.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Henriksen, K.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Holmes, J. M.

Lorentzen, D. A.

Moen, J.

Partamies, N.

N. Partamies, M. Syrjäsuo, and E. Donovan, "Using colour in auroral imaging," Can. J. Phys. 85, 101-109 (2007).
[CrossRef]

Romick, G.

Sandholt, P. E.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Sigernes, F.

Sivjee, G. G.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Smith, R.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Svenøe, T.

Sweeney, P.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

Syrjäsuo, M.

N. Partamies, M. Syrjäsuo, and E. Donovan, "Using colour in auroral imaging," Can. J. Phys. 85, 101-109 (2007).
[CrossRef]

Appl. Opt.

Can. J. Phys.

N. Partamies, M. Syrjäsuo, and E. Donovan, "Using colour in auroral imaging," Can. J. Phys. 85, 101-109 (2007).
[CrossRef]

J. Geophys. Res.

C. S. Deehr, G. G. Sivjee, A. Egeland, K. Henriksen, P. E. Sandholt, R. Smith, P. Sweeney, C. Duncan, and J. Gilmer, "Ground-based observations of F Region Aurora associated with the Magnetospheric Cusp," J. Geophys. Res. 85, 2185 - 2192 (1980).
[CrossRef]

J. Opt. Technol.

Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci.

G. W. Chang, and Y. C. Chen, "Spectral responsivity estimator for color vision systems: filter selection and noise effect," Proc. Natl. Sci. Counc. Repub. China Part A: Appl. Sci. 25, 115 - 126 (2001).

Other

J. W. Chamberlain, Physics of the Aurora and Airglow, (Academic Press, New York and London, 1961).

M. H. Rees, Physics and chemistry of the upper atmosphere, (Cambridge University Press, 1989).
[CrossRef]

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 (8)

Fig. 1.
Fig. 1.

Experimental setup in the optical laboratory at UNIS. (1) fiber bundle from Leica 150 W Tungsten Halogen lamp, (2) camera mount, (3) order sorting filter wheel, (4) HR320 monochromator, (5) exit slit holder, (6) baffle, (7) fiber bundle to FICS spectrograph, (8) Lambertian screen, (9) FICS spectrograph, (10) steel mount rod.

Fig. 2.
Fig. 2.

Optical diagram. (1) lamp input fiber bundle, (2) f-matching lens, (3) order sorting filter wheel, (4) entrance slit, (5) flat mirror, (6) concave mirror (collector), (7) reflective grating, (8) focusing mirror, (9) flat mirror, (10) exit slit, (11) Lambertian diffuse re-emitting surface, (12) DSLR camera, (13) input fiber bundle to FICS spectrograph.

Fig. 3.
Fig. 3.

Source functions. C i (λ) is the set of observations that consists of 31 spectra from the monochromator (HR320) illuminating the diffuse screen (Lambertian surface SRT-99-180).

Fig. 4.
Fig. 4.

Block diagram of data handling. α(k) i is the total raw counts of the decomposed k-colour plane from observation i. β (k) is the corresponding total dark counts.

Fig. 5.
Fig. 5.

Raw data. Panel (A) shows raw counts from the Nikon D70 camera for each color channel. The palette in the upper left corner is the processed JPEG images from the camera for each observation. Panel (B) shows the corresponding results from the Nikon D200 camera.

Fig. 6.
Fig. 6.

The spectral responsivity. Panel (A) shows the spectral responsivity of the Nikon D70 camera for each color channel. Panel (B) shows the corresponding results from the Nikon D200 camera.

Fig. 7.
Fig. 7.

Samples of night- and dayside spectra of the aurora from the Kjell Henriksen Observatory (KHO) on Svalbard, Norway. Both spectra are obtained by the Auroral Spectrograph (ASG) owned by the National Institute of Polar Research in Japan (NIPR). The spectral range is 4172 to 7334 Å with a medium spectral resolution of ~25 Å. The exposure time is 1 second for both samples. The dayside spectrum (blue curve) is taken 18th of January 2008 at 07:29:41 UT. The night side spectrum (red curve) is from 3rd of February 2008 at 21:46:47 UT. All of the known atomic- and molecular bands of the aurora are marked as a function of wavelength according to [2]. The right y-axis shows the intensity in R/Å. The colored dash - dotted and dotted lines show the spectral responsitivities of the Nikon D200 and the D70, respectively.

Fig. 8.
Fig. 8.

The main colours of the aurora. The illustration is based on a photograph taken by a Fujifilm S2 Pro camera from the SVALSAT satellite station close to Longyearbyen, Norway, at 16:04:48 UT 8th of November, 2002. The exposure time was 30 seconds and the sensitivity was set to ISO 1600.

Tables (1)

Tables Icon

Table 1. The Nikon D70 and D200 total counts for each colour channel in %. The counts are calculated for both night- and dayside aurora.

Equations (5)

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

1 R ( 1 4 π ) × 10 6 # photons cm 2 sec 1 sr 1 ,
u i ( k ) = C i ( λ ) · S ( k ) ( λ ) d λ , [ C T S ]
u i ( k ) = C ̂ i T · S ̂ ( k ) .
u ̂ ( k ) = C · S ̂ ( k ) ,
C = [ C 1 C 2 C 3 C 31 ] T .

Metrics