Astrophysics Laboratory

Observational Astronomy

 

Lecturer: Santiago González-Gaitán

Duration: 22nd September to 20th October

Classes: Mondays 5-7pm and Tuesdays 2-5pm.


Material to be covered

1) Basics of astronomical targets: planets, moons, stars, nebulae, galaxies

2) Astronomical observations: coordinate systems, time systems, magnitudes, photometry, colors

2) Planning observations: ephemerides, planetariums, observing proposals

3) Telescopes and cameras, photometry, spectrography, exposure times

4) CCD noise, image analysis and data reduction: bias, darks, flats, hot pixels, cosmic rays

5) Data analysis, statistics and visualization

6) Scientific writing, literature

 

Hands-on and data analysis: scientific projects

In this course we will develop a scientific project to be elaborated in small groups in which we will go through the different scientific steps of an observational astronomer: writing an observing proposal, planning and performing observations with a telescope, reducing and analyzing the data, writing a research report or paper. 

This semester we will use data already taken with the FORS instrument at the Very Large Telescope in Paranal, Chile. 

 

Evaluation

Observing Proposal: 25%

Data products (images, figures, codes): 15%

Final short paper: 40%

Final presentation: 20%

 

Software:

The following free software is required. You should install them beforehand.

- python3: astropy, astroplan, photutils

- astrometry.net

- ds9

- stellarium

 

Useful material:

·      Visibility tools:

                        https://observability.date/

                        http://catserver.ing.iac.es/staralt/

·      Exposure time calculator:

            Generic: https://www.mirametrics.com/sn_calculator_mvn.php

            ESO: https://www.eso.org/observing/etc/

·      Field of view calculator:

           https://www.skyatnightmagazine.com/astronomy-field-view-calculator/

·      Databases of astronomical sources:

            NED: https://ned.ipac.caltech.edu/

            CDS: https://cdsportal.u-strasbg.fr/

·      VLT/FORS2 Telescope and instrument info:

            https://www.eso.org/sci/facilities/paranal/instruments/fors/overview.html

            Overheads: https://www.eso.org/sci/facilities/paranal/cfp/cfp102/overheads.html

·      Light pollution:

            https://www.lightpollutionmap.info/#zoom=4&lat=5759860&lon=1619364&layers=B0FFFFFTFFFFF

·      Moon brightness:

            http://www.gemini.edu/sciops/telescopes-and-sites/observing-condition-constraints/optical-sky-background


Scientific Projects

The course is based on the elaboration of a scientific project that should be carried out in groups of maximum three students. Below a list of possible projects and a simple description are presented. It is expected that the students will research on the chosen topic and prepare a) an observing proposal, b) reduce and analyze VLT/FORS2 data, and d) write a scientific report in paper format of the full project.

 

Additionally, independent of the chosen topic, every group should make a composite color image of the studied object.

 

The following is a list of possible projects:

1) Stellar cluster

            Scientific questions:   

                        What is a stellar cluster? What is its age? What is the turnoff point?

            Skills: 

                        Basic: bias, dark, flat subtraction; standard star

                        Stellar photometry of each star

                        Catalog matching and membership search

                        Plot the stars in a Hertzsprung-Russell diagram

                        Fitting of isochrones

            Possible Targets:

                        Open clusters: Jewel Box, NGC-2362

                        Globular clusters: 47Tuc, M12

 


2) Galaxy

            Scientific questions:   

                        How is the luminosity and color of a galaxy distributed and why? What are the properties of a galaxy?

            Skills: 

                        Basic: bias, dark, flat subtraction; standard star

                        Isophotal photometry

                        Measure luminosity profile and integrated luminosity of a galaxy

                        Obtain Sérsic profile

                        Fitting of stellar populations

            Possible Targets:

                        M61, NGC-1398, M87, NGC-1404, NGC-7098, NGC-5426/NGC-5427, NGC-3981, M77, M83, NGC-7424, NGC-4981, NGC-1448

 

ESO Data:

https://archive.eso.org/eso/eso_archive_main.html

https://baltasar.tecnico.ulisboa.pt/~sgonzalez/LabAst577_2020


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