Physics of auroral phenomena : proceedings of the 33rd Annual seminar, Apatity, 02 - 05 March, 2010 / [ed.: A.G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 206 с. : ил.
“Physics o fAuroral Phenomena”, Proc. XXXIIIAnnual Seminar, Apatity, pp. 41 - 45, 2011 © Kola Science Centre, Russian Academy of Science, 2011 Polar Geophysical Institute THE STELLACAMII AS AN ALL-SKY IMAGER DURING THE SCIFER 2 ROCKET CAMPAIGN F. S i g e m e s E . L u n d b e rg 2, A. Skjaeveland l, J. M. Holmes M. Dyrland N. Peters D. A Lorentzen K. Oksavik M. M e lla 3, K. L y n c h 3, Y. O g aw a 4, M. R. Lessard 5, and P. M. K in tn e r2 1. University Centre in Svalbard (UNIS), N-9171, Longyearbyen, Norway 2. Cornell University, Ithaca, New York, USA 3. Dartmouth College, Hanover, New Hampshire, USA 4. National Institute o f Polar Research, Tokyo, Japan 5. University o f New Hampshire - Durham, USA Abstract. Due to the rise of the moon and sun during the SCIFER 2 (Sounding of the Cusp Ion Fountain Energization Region) rocket campaign over Svalbard in mid January 2008, it was necessary to come up with a solution to monitor the sky and aurora without using intensified camera systems. The reason is that intensifiers become damaged if they are illuminated directly by the moon or from scattered light from the sun. It was decided to test a simple and commercially available solution based on a fisheye lens and a video camera used by the astronomical community. The camera successfully detected satellites, stars and weak dayside aurora. Stars were used to find the camera orientation and to evaluate the lens performance. Finally, an animation is compiled to identify the target aurora and locate the source area of ion outflow sampled by the rocket. 1. Short background The test was carried out at the new optical laboratory for auroral research at Breinosa (78.15° N, 16.04° E) close to Longyearbyen, Svalbard. The site named the Kjell Henriksen Observatory (KHO) was used as scientific command centre for the SCIFER 2 rocket campaign in early January, 2008. More than 15 optical instruments from several institutions around the world supported the campaign. A mosaic o f ground based data of the dayside aurora was presented in real time to the primary investigator o f the campaign. The campaign started on 2 January with a launch window from 05 to 11 UT. The time slot for the whole campaign was chosen centered around the new moon at 7 January. The last day of the campaign was planned to be 15 January. Due to bad weather, low solar activity and numerous other reasons the rocket was not launched. It was then decided to try 5 more days. At this stage the intensified all-sky video camera turned off automatically, since the moon was above the horizon. And even worse, scattered light from the rising sun became more and more evident. Our scanning photometers also turned off when the sun reached and elevation of 10 degrees below the horizon. As a result, the optical support to the campaign was limited to the period 05 - 09 UT. Under these conditions something had to be done in order for us not to be totally blinded by the moon and the sun. We decided to quickly assemble with available components an all-sky camera without the use o f an intensifier. The sensitivity and resolution of the obtained images were of sufficient quality to monitor the dayside aurora in near real time. Finally, the Black Brant XII rocket was launched on 18 January from Andoya Rocket Range in northern Norway at 07:30 UT. The rocket successfully studied ion outflow in the cleft region of the magnetosphere associated with dayside aurora over Svalbard [Kintner et a l, 1996]. A description of the camera together with its performance and results are reported below. Satellites are identified and stars are used to find the attitude or alignment of the camera during the launch o f the rocket. The rocket’s on board GPS data record has been used to calculate the view angles and to produce an animation as seen by the camera during the flight. The target aurora is clearly identified. 2. Parts and components The sensor head is a video camera named StellaCam II purchased from the company Adirondack Video Astronomy and a circular CS-mount fisheye lens from Fujinon. See Fig. 1. The camera also known as the WATEC 120N uses a Zi" CCD chip from SONY (ICX-418ALL) that claims to operate under a minimum illumination of 0.00002 lux with a F/1.4 lens as front optics. The output is a real time frame accumulated video CCIR (PAL) signal that is stored to disk every second by a PC frame grabber. Each frame is 320 by 240 pixels at 8 bit gray scale resolution. A remote control box is used to manually set parameters such as gain, gamma correction, and number of frames to accumulate to improve the signal to noise. In our case, the gain controller was turned to half o f its range (8-3 8dB), the gamma correction to 1.0, and the frame accumulation was set to 32. This results in a repetition / update rate of about 1 second for each stored frame. 41
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