1Institute of Space Systems, University of Stuttgart, Pfaffenwaldring 29,
70569 Stuttgart, Germany
2Universitätssternwarte Oldenburg, Institute of Physics and
Department of Medical Physics and Acoustics, Carl von Ossietzky University,
26129 Oldenburg, Germany
3European Space Agency, ESA/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk
4Chair of Astronautics, Technical Univ. Munich, Boltzmannstraße 15,
85748 Garching, Germany
5International Meteor Organisation, Abenstalstr. 13b, 84072 Seysdorf,
Received: 18 Aug 2016 – Discussion started: 24 Oct 2016
Abstract. In this paper, we analyse the technical biases of two intensified video cameras, ICC7 and ICC9, of the double-station meteor camera system CILBO (Canary Island Long-Baseline Observatory). This is done to thoroughly understand the effects of the camera systems on the scientific data analysis. We expect a number of errors or biases that come from the system: instrumental errors, algorithmic errors and statistical errors. We analyse different observational properties, in particular the detected meteor magnitudes, apparent velocities, estimated goodness-of-fit of the astrometric measurements with respect to a great circle and the distortion of the camera.
Revised: 30 Jan 2017 – Accepted: 01 Feb 2017 – Published: 27 Feb 2017
We find that, due to a loss of sensitivity towards the edges, the cameras detect only about 55 % of the meteors it could detect if it had a constant sensitivity. This detection efficiency is a function of the apparent meteor velocity.
We analyse the optical distortion of the system and the
goodness-of-fit of individual meteor position measurements relative to a fitted great circle. The astrometric error is dominated by uncertainties in the measurement of the meteor attributed to blooming, distortion of the meteor image and the development of a wake for some meteors. The distortion of the video images can be neglected.
We compare the results of the two identical camera systems and find systematic differences. For example, the peak magnitude distribution for ICC9 is shifted by about 0.2–0.4 mag towards fainter magnitudes. This can be explained by the different pointing directions of the cameras. Since both cameras monitor the same volume in the atmosphere roughly between the two islands of Tenerife and La Palma, one camera (ICC7) points towards the west, the other one (ICC9) to the east. In particular, in the morning hours the apex source is close to the field-of-view of ICC9. Thus, these meteors appear slower, increasing the dwell time on a pixel. This is favourable for the detection of a meteor of a given magnitude.
Albin, T., Koschny, D., Molau, S., Srama, R., and Poppe, B.: Analysis of the technical biases of meteor video cameras used in the CILBO system, Geosci. Instrum. Method. Data Syst., 6, 125-140, doi:10.5194/gi-6-125-2017, 2017.