The following Python modules are used in AsPyLib (v1.2.2):

- Pyfits

- Numpy

- Scipy

- Matplotlib

- Parallel Python

- vo.table

Calculating median values for large amounts of data (such as for stacking CCD images) in reasonable times can be difficult. In AsPyLib we use a very efficient piece of C code written by N.Devillard (based on the Wirth method). See here for more information.

The code to perform the Bspline interpolation, used in AsPyLib for most geometrical transforms (translation, rotation, scaling) but also for photometry, is taken from P.Thevenaz.

The original code can be found at this link, with all the explanations on how to use it.

Some useful papers about Bsplines (the .pdf can be found with Google):

- P. Thévenaz, T. Blu, M. Unser, "Interpolation Revisited", IEEE Transactions on Medical Imaging, vol. 19, no. 7, pp. 739-758, July 2000.
- R. Seta, K. Okubo, N. Tagawa, "Digital image interpolation method using higher-order interpolating polynomials with compact finite-difference", proceedings of 2009 APSIPA annual summit and conference, Sapporo, Japan, Oct 4-7, 2009, pp406-409.
- J. Pan, "Image interpolation using spline curves", see here
- M. Unser, A. Aldroubi, M. Eden, "Fast B-spline transforms for continuous image representation and interpolation", IEEE trans. on pattern analysis and machine intelligence, vol.13, no.3, pp 277-285 (1991).

In the first paper ("Interpolation revisited") a performance comparison between many possible algorithms is presented. The cubic Bspline interpolation turns out to be very accurate. This paper also explains quite clearly that the Bspline functions are not interpolating kernels but are used as a basis for image representation. The Bspline interpolation kernels are given in the paper from M.Unser.

Some important papers about aperture photometry:

- S.B. Howell, "Two-dimensional aperture photometry: Signal-to-noise ratio of point source observations and optimal data-extraction techniques", PASP, vol.101, pp616-622 (1989).
- H. Kjeldsen, S. Frandsen, "High-precision time-resolved CCD photometry", PASP, vol.104, pp 413-434 (1992).
- P. Ryan, "Scintillation reduction method for photometric measurements", PASP, vol.110, pp 1235-1248 (1998).

The Howell paper is quite famous, and describes the principle of aperture photometry. However the noise analysis may be a bit simple. The second paper ("High-precision...") gives a more in-depth analysis of all sources of noise and perturbations.

The paper from Ryan explains in detail what is scintillation noise and how it scales with wavelength, telescope aperture, etc.

- E. Bertin, S. Arnouts, "Sextractor: software for source extraction", Astron. Astrophys. Suppl. Ser., vol.117, pp 393-404 (1996).
- E. Bertin, "Automatic astrometric and photometric calibration with SCAMP", see link here
- J. Irwin, M. Irwin, S. Aigrain, S. Hodgkin, L. Hebb, E. Moraux, "The Monitor project: data processing and lightcurve production", link on Arxiv (14 Dec 2006).
- N. Kaiser, G. Wilson, G. Luppino, H. Dahle, "A photometric study of the supercluster MS0302 with the UH8K CCD camera: image processing and object catalogs", link on arXiv (16 Jul 1999).
- D.L. Pollacco et al., "The WASP project and the SuperWASP cameras", link on arXiv (22 Aug 2006).
- Y. Damerdji, A. Klotz, M. Boer, "The Tarot suspected variable star catalog", The Astronomical Jourmal, vol.133, pp 1470-1477 (2007).

An interesting algorithm for astrometric reduction is described in the Kaiser paper. In particular, an efficient method is given to quickly find the scaling and rotation laws to match an image with a star catalog.

- J. Meeus, "Calculs astronomiques à l'usage des amateurs", Société Astronomique de France, Paris, 1986.
- A.U. Landolt, K.L. Blondeau, "The calculation of heliocentric corrections", PASP, vol.84, pp 784-809 (1972).

The principles of fitting a periodic lightcurve with Fourier series are explained (in French) at this link that describes the CourbRot software.

The link to CourbRot.exe is broken since a long time (2010) but the following link should work: click here.

AsPyLib library

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Dauban Survey

- MAIN PAGE
- Setup description
- Catalog of discoveries
- Corrections for known variables
- ARCHIVE
- Old setup (Jan 2012-Aug 2012)
- RR Lyr 2012 campaign
- Asteroids and fast variables
- Observation of artificial satellites
- LINKS
- Observatoire Chante-Perdrix Dauban (IAU A77)

Other things done with AsPyLib