Observational astrophysics

Physics, First Cycle
Educational Physics
3 year
Hours per week – 1. semester:

Enrollment in academic year.

Content (Syllabus outline)

Coordinate systems (alt-azimuthal, equatorial, ecliptic, galactic), their transformations, including coordinate precession.
Modern telescopes: primary, Newton, Cassegrain, Nasmyth, Coude focus, use of optical fibers. Rayleigh condition for a lens and mirror. Reflectivity of materials in optical, UV and IR light. Techniques of mirror making and telescope mounts, cases of Schmidt, LSST, and Lamost.
Aberrations: spherical aberration and parabolic mirror, coma, astigmatism, field curvature, image distortion. Point diagrams for various Cassegrain types (Ritchey-Chretien, classical,...). Diffraction errors.
Digital detectors: quantum efficiency, linearity, dynamic range, image digitalization and analysis. CCD detector: basic principle (Si, Ga-As type), Poisson noise, dark current, read-out noise, S/N equation, calibrations with flat field and bias exposures. Thick and thinned devices, deep-depletion devices, low-light-level CCDs and their S/N equation, photon counting mode. Basic comparison of CCD and CMOS.
Photometry: photometric systems, color index, color correction, correction of atmospheric extinction, bolometric correction, properties and correction of interstellar reddening and extinction, their spatial distribution.
Spectroscopy in visual domain: Boller&Chivens spectroscope, interference condition. Point size as a function of CCD pixel size, camera and collimator quality, slit-width and grating magnification. Resolving power as a function of size and density of the grating, wavelength, slit width and telescope size. Comparison of reflective and transmissive grating, comparison with prism. Long-slit mode, slitless mode, use of optical fibers, echelle spectrograph. Basics of reduction of spectroscopic observations.
Stellar spectra: intensity and width of spectral lines, occurence of absorption edges, observable quantities in single and double-star spectra, basic relations for the Roche model. Telluric absorption and emission lines, polar lights, zodiacal light.
Non-stellar sources: types of nebulae (absorption, reflection, emission, H II regions, planetary, supernova remnants), mechanisms of absorption and radiation, size of the Stromgren sphere, semi-forbidden and forbidden lines in planetary nebulae, examples of nebular spectra, emission cores of spectral lines in stars, stellar winds and P Cygni line profiles. Active galactic nuclei, superluminal motion and gravitational lensing.
Observations in non-visual light: transparency of Earth atmosphere, radio and X-ray telescopes.


W.M. Smart: Spherical Astronomy, Cambridge Univ. Press, 1965 (3 poglavja/chapters).
The Astronomical Almanac, London Stationery office Publ. Centre, 2013.
Hale Bradt: Astronomy Methods, Cambridge Univ. Press, 2004.
Frank Shu: The Physical Universe, Univ. Science Books, 1982.
Lawrence H. Aller: Atoms, Stars and Nebulae, Harvard Univ. Press, 1971 (poglavja/chapters 1-7).
David F. Gray: The observation and analysis of stellar photospheres, Cambridge Univ. Press, 1992 (izbrana poglavja, selected chapters).
T. Zwitter in U. Munari: An introduction to analysis of Boller & Chivens spectra with IRAF, Asiago Monografie vol. 1, 1999.
Pierre Lena: Observational Astrophysics, Springer, 1988.

Objectives and competences

Mastering of theory and practical results of astronomical observations, with an emphasis on spectroscopic observations. Practical use various tools and interpretation of astrophysical literature.

Intended learning outcomes

Knowledge and understanding: Understanding of astrophysical interpretation of astronomical observations.

Application: Use of knowledge of physics to interpret astrophysical phenomena.

Reflection: Obtaining experience to follow current scientific developments and news related to the Universe.

Transferable skills: Digidal data manipulation, building of numerical simulations, use of large data-manipulation packages, understanding and practical use of original scientific literature, use of databases.

Learning and teaching methods

Lectures, numerical exercises, astro-lab reports.


Written exam, presentation of astro-lab reports
Oral exam
grading: 5 (fail), 6-10 (pass) (according to the Statute of UL)

Lecturer's references

Doc. dr. Janez Kos
1. Kos, J., Zwitter, T. 2013, Astrophysical Journal, 774, 72, »Properties of Diffuse Interstellar Bands at Different Physical Conditions of the Interstellar Medium«
2. Kos, J. ,et al. 2013, Astrophysical Journal, 778, 86, »Diffuse Interstellar Band at 8620 A in RAVE: A New Method for Detecting the Diffuse Interstellar Band in Spectra of Cool Stars«
3. Kos, J., et al. 2014, Science, 345, 791, »Pseudo-three-dimensional maps of the diffuse interstellar band at 862 nm«
4. Kos, J., et al. 2017, Monthly Notices of the Royal Astronomical Society, 464, 1259, »The GALAH survey: the data reduction pipeline«
5. Kos, J. 2017, Monthly Notices of the Royal Astronomical Society, 468, 4255, »Spatial structure of several diffuse interstellar band carriers«
6. Kos, J., et al., 2018, Monthly Notices of the Royal Astronomical Society, 473, 4612, »The GALAH survey: chemical tagging of stellar clusters and new members in the Pleiades«
7. Kos, J., et al. 2018, Monthly Notices of the Royal Astronomical Society, 480, 5242, »The GALAH survey and Gaia DR2: (non-)existence of five sparse high-latitude open clusters«
8. Kos, J., et al. 2018, Monthly Notices of the Royal Astronomical Society, 480, 5475, »Holistic spectroscopy: complete reconstruction of a wide-field, multiobject spectroscopic image using a photonic comb«