Intra-Pixel Sensitivity Variation and Charge Transfer Inefficiency — Results of CCD Scans

Toyozumi, Hiroyuki; Ashley, M. C. B.

doi:10.1071/as05013

Cited by 28 publications

(22 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The origins of the asymmetric component is still not clear. With the clues given by the analysis methods in this paper, it may source from the asymmetric instrumental profile, the CTI effect (Toyozumi & Ashley 2005;Murphy et al 2012), the imperfect light injection and the envelop-background problem of the current LFCs (Milakovic et al 2017), or a mixture of all the sources above which are estimated to generate about several tens of cm s −1 uncertainties. To understand the origins of line skewness can help push down the RV precision below 1 m s −1 and keep stable for long-term scale.…”

Section: Discussionmentioning

confidence: 99%

Statistical modelling of an astro-comb for high-precision radial velocity observation

Zhao

Liu

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

The advent of the laser frequency comb as the wavelength calibration unit allows us to measure the radial velocity at cm s −1 precision level with high stability in long-term, which enable the possibility of the detection of Earth-twins around solar-like stars. Recent study shows that the laser frequency comb can also be used to measure and study the precision of the instrumental system including the variations of line profile and the systematic uncertainty and instrumental drift. In this paper, we present the stringent analysis of a laser frequency comb(LFC) system with 25GHz repetition frequency on a R∼50,000 spectrograph with the wavelength spanning from 5085Å to 7380Å. We report a novel fitting model optimized for the comb line profile, the constrained double Gaussian. The constraint condition is set as µ 1,2 − µ < √ 2ln2σ. We introduce Bayesian information criterion to test various models. Compared to the traditional Gaussian model, the CDG(Constrained Double Gaussians) model provides much better goodness of fit. We apply the CDG model to the observed comb data to demonstrate the improvement of RV precision with CDG model. We find that the improvement of CDG model is about 40%∼60% for wavelength calibration precision. We also consider the application to use the LFC and CDG model as a tool to characterize the line shape variation across the detector. The motivation of this work is to measure and understand the details of the comb lines including their asymmetry and behaviors under various conditions, which plays a significant role in the simultaneous calibration process and cross-correlation function method to determine the Doppler shift at high precision level.

show abstract

Section: Discussionmentioning

confidence: 99%

Statistical modelling of an astro-comb for high-precision radial velocity observation

Zhao

Liu

et al. 2018

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…The non-uniformity can be measured with a source of light focused in a spot smaller than the pixel size. 6 The geometrical size of the spot in the described apparatus setup is smaller than the pixel size, but the PSF causes the light to be spread over several pixels. The way to restrain the PSF is to put a circular aperture in the front of the lenses.…”

Section: Intra-pixel Measurementsmentioning

confidence: 99%

Laboratory measurements of the "Pi of the Sky" optical system

2009

View full text Add to dashboard Cite

The ultimate goal of the "Pi of the Sky" apparatus is observation of optical flashes of astronomical origin and other light sources variable on short timescales, down to tens of seconds. We search mainly for optical emissions of Gamma Ray Bursts, but also variable stars, novae, blazars, etc. This task requires a precise photometry -accurate measurement of the source's brightness (and it's variability). "Pi of the Sky" single cameras' field of view is about 20 • × 20 • . This causes a significant deformation of a point spread function (PSF), reducing quality of brightness measurement with standard photometric algorithms. To improve photometry, an attempt to investigate PSF based on real star images was made. However, results turned out to be inconclusive due to miscellaneous sky-observing effects. Therefore we decided to perform laboratory measurements, using a CCD camera and an artificial light source as a star simulator. This work shows preliminary results of this study -a set of high resolution PSF shapes, pixel response and pixel sensitivity functions. Finally, an idea how to simulate a real star image in the "Pi of the Sky" system is presented.

show abstract

“…Due to the steep and peaked shape of the PSF, the subpixel sensitivity distribution had to be considered. A model similar to the one described in Toyozumi & Ashley (2005) was used. Figure 6 (middle panel) shows the assumed sub-pixel sensitivity variation for several pixels.…”

Section: Instrumentmentioning

confidence: 99%

Brite‐Constellation: A status report

Kuschnig¹,

Weiss²,

team³

2012

Astron Nachr

View full text Add to dashboard Cite

The BRITE-Constellation, short for "BRIght Target Explorer" Constellation, is a group of six nanosatellites from Austria, Poland and Canada carrying thirty millimeter aperture optical telescopes with a CCD camera. The goal of the mission is to photometrically measure low-level oscillations and temperature variations of the brightest stars in the sky down to a visual magnitude of 4.0, with unprecedented precision and time coverage not achievable from ground in two colors. The improved three-axis pointing performance which is a critical element that makes this high precision photometry mission feasible is a recent development by the University of Toronto's Space Flight Laboratory. The University of Vienna and the FFG/ALR (Austria's space agency) are financing the development of two satellites. The Polish Academy of Sciences is funding two additional satellites as well as the Canadian Space Agency resulting in six components for the constellation.

show abstract

Intra-Pixel Sensitivity Variation and Charge Transfer Inefficiency — Results of CCD Scans

Cited by 28 publications

References 11 publications

Statistical modelling of an astro-comb for high-precision radial velocity observation

Statistical modelling of an astro-comb for high-precision radial velocity observation

Laboratory measurements of the "Pi of the Sky" optical system

Brite‐Constellation: A status report

Contact Info

Product

Resources

About