https://polaris.astro.physik.uni-potsdam.de/wiki/ Wed, 08 Apr 2026 03:24:50 +0000 FeedCreator 1.8 https://polaris.astro.physik.uni-potsdam.de/wiki/lib/exe/fetch.php?media=wiki:logo.png https://polaris.astro.physik.uni-potsdam.de/wiki/ https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:doodle&rev=1752087146&do=diff The last seminar of the current semester anonymous@undisclosed.example.com (Anonymous) Wed, 09 Jul 2025 18:52:26 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:gdl&rev=1466040662&do=diff GDL (IDL) for beginners The programming language GDL -- a free variant of IDL -- uses library functions that were specially designed for the analysis of astrophysical data and includes routines to read and write FITS files. The interpreter is started in the console with:$i>2^{15}-1=32767$ anonymous@undisclosed.example.com (Anonymous) Thu, 16 Jun 2016 01:31:02 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:index&rev=1716458072&do=diff The laboratory courses Two lab courses are offered for the bachelor's and master's degree programs. Please pay attention to the admission requirements for the different laboratory courses. In the following sections the laboratory courses and their target groups are presented: anonymous@undisclosed.example.com (Anonymous) Thu, 23 May 2024 09:54:32 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:ism&rev=1504798754&do=diff D1 - Interstellar absorption spectroscopy Task A UV spectrum of Delta Orionis (a nearby star) is given, showing several interstellar absorption lines of different ions and molecules. These lines arise from interstellar gas clouds between the emitting star and the earth. Using computer programs, the properties of these lines are examined and the column density of the contributing ions and molecules are calculated. With the column densities the element abundances and further physical properties… anonymous@undisclosed.example.com (Anonymous) Thu, 07 Sep 2017 15:39:14 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:massenverlust&rev=1504798778&do=diff D2 - Estimating the mass loss rate of OB stars Task Massive, hot stars (spectral types O and B) emit parts of their radiation in the Radio band. Wright & Barlow (1975) developed a simple model to calculate free-free-emission of stellar winds (see the script of the stellar atmospheres lecture!). At least of three OB stars (e.g. HD66811 ($\zeta$$\dot{M}$$v_{\infty}$$v_{\infty}$$1150-1980\,\unicode{x212B}$$1850-3350\,\unicode{x212B}$$1548.188\,\unicode{x212B}$$1550.762\,\unicode{x212B}$$v_{\infty… anonymous@undisclosed.example.com (Anonymous) Thu, 07 Sep 2017 15:39:38 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:namenskonvention&rev=1774878048&do=diff Name conventions This article documents the conventions for file and directory names on columba, the computer used for data reduction in the astronomical laboratory courses. Working directory In your home directory you will find the directory data_reduction anonymous@undisclosed.example.com (Anonymous) Mon, 30 Mar 2026 13:40:48 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:nist&rev=1550490861&do=diff NIST The National Institute of Standards and Technology (NIST) hosts a data base of spectroscopic transitions for a variety of elements and their ions. This data base is an excellent tool for identifying spectral lines in stellar spectra. This article is a short introduction on how to use this web page.$f_{ik}$$10^{-3}$$f_{ik}$$5000\,\unicode{x212B}$$6000\,\unicode{x212B}$ anonymous@undisclosed.example.com (Anonymous) Mon, 18 Feb 2019 11:54:21 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:organisation_bachelor&rev=1744288673&do=diff Organizational matters - Summer Semester 2025 This article documents all agreements, arrangements, talks, etc. within the scope of the astronomical laboratory course. Talk program This is the current program: Datum/Date Vortrag/Talk Vortragender/Speaker anonymous@undisclosed.example.com (Anonymous) Thu, 10 Apr 2025 12:37:53 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:organisation_master&rev=1744288637&do=diff Organizational Matters - Summer Semester 2025 This article documents all agreements, arrangements, talks, etc. within the scope of the astrophysical laboratory course. Talk program For a comprehensive overview of how to prepare talks in a scientific context, see: anonymous@undisclosed.example.com (Anonymous) Thu, 10 Apr 2025 12:37:17 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:photometrie_python&rev=1774596030&do=diff N2 - Photometry of open star clusters Remark: This article describes the modern data reduction and data analysis for the N2 experiment using an almost fully automated Python script for the reduction of flatfields and dark frames as well as the stacking and alignment of the star cluster images. The classical version, where the displacements are measured by hand and manually entered into a routine, is described in the article $(B-V)_{0} = (B-V) - E_{(B-V)}$$V_{0} = V - A_{V}$$E_{(B-V)}$$(B-V)$$(B… anonymous@undisclosed.example.com (Anonymous) Fri, 27 Mar 2026 07:20:30 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:photometrie&rev=1695106360&do=diff N2 - Photometry of open star clusters (GDL) Remark: This article describes the modern data reduction of N2 with help of an half automatic GDL pipeline. In comparison to the classical version (only in German so far), the offsets between the exposures (flatfields, darkframes, and the individual exposures in the different filters) are calculated by the script.$x_b$$\Delta x_v = x_{v} - x_{b}$$N \times M$$N - \Delta x_{v}$$\Delta x_i$$\Delta y_i$$(B-V)_{0} = (B-V) - E_{(B-V)}$$V_{0} = V - A_{V}$$… anonymous@undisclosed.example.com (Anonymous) Tue, 19 Sep 2023 06:52:40 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:protocol&rev=1632237706&do=diff How to write a lab course report Here we give a few advises regarding the writing of a report within the scope of the astrophysical lab course. We aim to give an overview over what should be included in those reports and which guidelines need to be followed. Those largely are similar to the requirements of future scientific writings like theses and journal papers. anonymous@undisclosed.example.com (Anonymous) Tue, 21 Sep 2021 15:21:46 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:reservation&rev=1773696843&do=diff Reservation of observations Reservation of night observations at the OST * Please log in with your username and password * Afterwards you will be able to see the booking form and a calendar, showing the occupancy * In the Name field please state the name of your group and the scheduled observations (e.g. anonymous@undisclosed.example.com (Anonymous) Mon, 16 Mar 2026 21:34:03 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sonnenrandverdunklung&rev=1467072804&do=diff Creation of a radial brightness profile The program ds9 can be used to create a radial brightness profile. In the following two possibilities will be described: Projection tool * Open the FITS file * Click on projection tool in Region > Shape > Projection anonymous@undisclosed.example.com (Anonymous) Tue, 28 Jun 2016 00:13:24 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sonnenrotation&rev=1689974651&do=diff S1 - Solar Rotation Task Calculate the rotational period of the sun from the Doppler shift of solar spectral lines at the eastern and western rim of the sun, respectively. Observation The observation will be performed with the solar telescope in the $\lambda_0\,[\mathrm{nm}]$ anonymous@undisclosed.example.com (Anonymous) Fri, 21 Jul 2023 21:24:11 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sonnenspektroskopie&rev=1689974897&do=diff S2 - Estimating the magnetic field strength in a sunspot Task Estimate the magnetic field strength in a sunspot, using the Zeeman splitting of spectral lines. Observation The observation will be performed with the solar telescope in the “Einsteinturm$\Delta \lambda$$B[\mathrm{T}] = \frac{4\pi m_\mathrm{e} c}{e} \cdot \frac{\Delta \lambda}{g\lambda_0^2} = 2.142\cdot 10^7\cdot\frac{\Delta \lambda[\mathrm{nm}]}{g\lambda_0^2[\mathrm{nm}^2]} = 2.142\cdot 10^4\cdot\frac{\Delta \lambda[\mathrm{pm}… anonymous@undisclosed.example.com (Anonymous) Fri, 21 Jul 2023 21:28:17 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sternspektren_baches&rev=1773649866&do=diff N1 - Stellar spectra of different spectral types (BACHES) The aim of this observation is to obtain an overview of different spectral types. Thus, we will give you the coordinates and the apparent magnitude of four stars of different spectral types that are well visible during the night of your observation.$R = \frac{\Delta \lambda}{\lambda}$ anonymous@undisclosed.example.com (Anonymous) Mon, 16 Mar 2026 08:31:06 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sternspektren&rev=1733828449&do=diff N1 - Stellar spectra of different spectral types (DADOS) These instructions are currently being revised as part of the move to enhanced evaluation software. However, the manual is currently complete. It can be used without further ado to evaluate the data. Just don't be surprised if you see anonymous@undisclosed.example.com (Anonymous) Tue, 10 Dec 2024 11:00:49 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:sunspot-temp&rev=1467072925&do=diff Estimating the temperature The temperature of a solar spot or a facula can be estimated from an intensity profile. Theory The Stefan-Boltzmann law gives a correlation between emitted radiative power P of a black body, the emitting area A, and its absolute temperature T:\begin{equation*} P = \sigma \cdot A \cdot T^4 \end{equation*}$P_1$$P_2$\begin{equation*} \frac{P_1}{P_2}=\frac{T_1^4}{T_2^4} \end{equation*} anonymous@undisclosed.example.com (Anonymous) Tue, 28 Jun 2016 00:15:25 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:versuche_bachelor&rev=1773645195&do=diff Astronomical laboratory course: observations Observations in the bachelor laboratory course: Every lab group usually has to complete seven observations. Since the fundamentals of the observations will be discussed in the seminar, the participants usually will start with a couple of observations using the eyepiece. It crucially depend on the observational conditions, if a specific observations can be carried out. During each observation a observational protocol needs to be filled out. A form can… anonymous@undisclosed.example.com (Anonymous) Mon, 16 Mar 2026 07:13:15 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:versuche_master&rev=1726639996&do=diff Astrophysical laboratory course: Observations Observations within the scope of lab course for master students: Depending on the weather conditions, the experiments S1, S2, N1, and N2 are scheduled. Both the observations and the data reduction of S1 and S2 are done together. For each night observation (N1 and N2) a protocol is required, see the prepared form: anonymous@undisclosed.example.com (Anonymous) Wed, 18 Sep 2024 06:13:16 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:wrstern&rev=1728461391&do=diff D3 - Spectral analysis of a Wolf-Rayet star Task Determine the temperature $T_*$, radius $R_*$, luminosity $L$, mass loss rate $\dot{M}$, the mass fraction of hydrogen $X_{\mathrm{H}}$, and the stellar wind's terminal velocity $v_{\infty}$ of the Wolf-Rayet star BAT99 58 (Brey 47) in the Large Magellanic Cloud (LMC) by comparison with synthetic spectra calculated with the PoWR stellar atmosphere code.$T_* > 10\,\mathrm{kK}$$R_{\mathrm{t}}$$1150-1980\,\unicode{x212B}$$1850-3350\,\unicode{x212B}… anonymous@undisclosed.example.com (Anonymous) Wed, 09 Oct 2024 08:09:51 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:zugang&rev=1774351174&do=diff Access to the Laboratory Computer There are two ways to analyse the data collected during the lab course: 1. Perform the analysis directly on the computer columba at the university (by prior arrangement). 2. Log in to this computer remotely from another system (e.g. from home) and perform the analysis there. anonymous@undisclosed.example.com (Anonymous) Tue, 24 Mar 2026 11:19:34 +0000 https://polaris.astro.physik.uni-potsdam.de/wiki/doku.php?id=en:praktikum:zugangsvoraussetzung&rev=1774738105&do=diff Overview of Admission Requirements Credit Recognition for Lab Courses The astrophysics lab courses consist of two core components, which can be credited to different modules depending on the degree programme. For bachelor's students we offer the Astronomical Lab Course anonymous@undisclosed.example.com (Anonymous) Sat, 28 Mar 2026 22:48:25 +0000