A new and improved method to obtain the average spectral pixel responsivity and the quantum efficiency of Digital Single Lens Reflex (DSLR) cameras is outlined. Two semi-professional cameras, the Nikon D300 and the Canon 40D, are evaluated. The cameras red, green and blue pixel responsivities and quantum efficiency are retrieved by illuminating an integrating sphere with a wavelength tunable monochromator. 31 intensity calibrated monochromatic spectral lines from 4000 to 7000 A, with a bandpass of approximately 12 A, were used as a library to solve the main equations of observation for the cameras. Both cameras have peak sensitivity in the blue and minimum sensitivity in the red. The Canon 40D has blue and green channel sensitivity close to the Nikon D300. The Canon red channel has half the sensitivity of the Nikon camera.
This work compares the methods by Starkov (1994a) and Zhang & Paxton (2008), that calculate the size and location of the auroral ovals as a function of planetary Kp index. The ovals are mapped in position and time onto a solar illuminated surface model of the Earth. It displays both the night-and dayside together with the location of the twilight zone as Earth rotates under the ovals. The graphical display serves as a tool to forecast auroral activity based on the predicted value of the Kp index. The forecast is installed as a service at http://kho.unis.no/. The Zhang & Paxton (2008) ovals are wider in latitude than the Starkov (1994a) ovals. The nightside model ovals coincide fairly well in shape for low to normal auroral conditions. The equatorward border of the diffuse aurora is well defined by both methods on the nightside for Kp 7. The dayside needs further studies in order to conclude.
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 A with a bandpass of approximately 12 A 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/A. 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 A, respectively. The response was high for the blue colour channel with a clear cut-off at 4100 A for the UV part of the spectrum. The red channel response indicates low sensitivity above 6600 A. 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 A in wavelength.
The results of research into the optical phenomena produced by rocket exhaust products in the upper atmosphere are presented. The data were obtained during routine observations of auroras by all-sky cameras from 1975 to 1990 from the Kola peninsula and Arckchangelsk region. The observed rocket launches were carried out from the Plesetsk and White Sea launch sites during both nighttime and twilight periods. The observed phenomena can be divided into two main types: local phenomena with long development times and relatively short-lived large-scale ones. The characteristic properties of both types are determined, in the first instance, by the type of rocket engines used (solid or liquid propellant) and their operating mode. The most intense, large-scale and dynamic phenomena are caused by separation of rocket stages and shutoff of solid-fuel rocket engines.
Abstract. This report presents data and analysis of visual, photographic and auroral spectral data, obtained by the Russian astronomer J. Sykora from the Russian-Swedish expedition to Spitsbergen during the 1899-1900 winter season, which are historically significant for auroral studies. These data seem to be the first instrumental observations of auroral spectra in the Arctic and some of the emissions discovered have world priority. The second known photos in the world of aurora from the Arctic and undoubtedly the first ones for geomagnetic latitudes of about 75 • in the Spitsbergen Archipelago were obtained. The results of the expedition are discussed from a modern point of view and compared with our knowledge of the 21st century. A description of the equipment and methods that were used by Russian astronomers is presented. Both photographic and spectral devices using registration by photographic plates were used, along with special methods of their development and enhancement. Some statistical analysis was done on the basis of the expedition reports and diaries. This analysis shows that by using Sykora's data it was possible to discover the auroral oval or instantaneous auroral distribution over the polar region. Analysis of photographic samples and sketches of the aurora demonstrate typical auroral form outlines as they are described today. Spectral plates exposed for several hours to auroral lights revealed not only the main auroral emissions, which were well-known at that time, but several other unidentified weak emissions, which were rediscovered and interpreted years later.
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