Publication details for Dr Richard WilsonOsborn, James, Wilson, Richard W., Dhillon, V. S., Avila, Remy & Love, Gordon D. (2011). Conjugate-plane photometry: reducing scintillation in ground-based photometry. Monthly Notices of the Royal Astronomical Society 411(2): 1223-1230.
- Publication type: Journal Article
- ISSN/ISBN: 0035-8711, 1365-2966
- DOI: 10.1111/j.1365-2966.2010.17759.x
- Keywords: Atmospheric effects, Techniques, Photometric.
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
High-precision fast photometry from ground-based observatories is a challenge due to intensity fluctuations (scintillation) produced by the Earth's atmosphere. Here we describe a method to reduce the effects of scintillation by a combination of pupil reconjugation and calibration using a comparison star. Because scintillation is produced by high-altitude turbulence, the range of angles over which the scintillation is correlated is small and therefore simple correction by a comparison star is normally impossible. We propose reconjugating the telescope pupil to a high dominant layer of turbulence, then apodizing it before calibration with a comparison star. We find by simulation that given a simple atmosphere with a single high-altitude turbulent layer and a strong surface layer, a reduction in the intensity variance by a factor of ∼30 is possible. Given a more realistic atmosphere as measured by Scintillation Detection and Ranging (SCIDAR) at San Pedro Mártir, we find that on a night with a strong high-altitude layer we can expect the median variance to be reduced by a factor of ∼11. By reducing the scintillation noise we will be able to detect much smaller changes in brightness. If we assume a 2-m telescope and an exposure time of 30 s, a reduction in the scintillation noise from 0.78 to 0.21 mmag is possible, which will enable the routine detection of, for example, the secondary transits of extrasolar planets from the ground.