HET615 - Major Project: Observational Astronomy
Unit Instructor: Dr Pamela Gay Format of the Unit: More details will be provided in Week 1, but the basic components of this Major Project unit will be:- A major project, chosen and approved by the project supervisor and unit instructor in or before Week 1 of Semester.
- A scientific justification, to be completed by the end of Week 3. Students must write a 3 page scientific justification of their project, clearly outlining the project aims, objectives and expected outcomes, as well as a detailed timetable of the project for the course of the semester. The purpose of the outline is to clearly establish that students are clear on exactly what they need to do for their project and understand the science behind it. This is broadly similar to "Observing Proposals" that research astronomers submit to apply for telescope time.
- Newsgroups will be used for general discussions of techniques and problems encountered, as well as for Project Diary postings, whereby students are expected to make brief weekly postings of what they accomplished, learned or tested that week. These submissions will not be marked but are a compulsory part of the major project. Students must submit Project Diary postings in at least 10 of the available weeks throughout the semester, otherwise they may receive a fail grade on their final project report.
- The major project report must be submitted at the end of semester (Week 12). The project report should be about 20 pages or as negotiated with the project supervisor as different types of projects may vary in length substantially.
- A final Poster to be submitted by the end of Week 13, in the style of a non-specialist conference poster. The poster should provide a general overall summary of the project, made up of a maximum of 4 pages (including images), written so as to be able to be understood by any SAO student.
Project 1: Radio Trends: Optically Identifying 20cm sources (Some Data Observed) Supervisor: Pamela Gay Outline:
Astronomers use radio sources to identify areas where they hope to find young stars, galaxies with star formation, and galaxies with active galactic nuclei. In this project, students will compare the radio and optical morphology of an instructor provided selection of six objects; half near the galactic pole and half near the galactic equator. Radio data will be downloaded from the New VLA Sky Survey (NVSS) database and (where possible) the Faint Image Radio Survey at Twenty centimeters (FIRST). Students will then optically identify each radio source using their own equipment. Final projects should discuss:
- how radio sources are optically identified, and what concerns must be addressed,
- the source of optical and radio emission in the projects objects, and how this effects the objects' apparent morphologies in each waveband, and
- the advantages and disadvantages of searching for specific objects in optical data versus radio data.
Students need a telescope with a FoV of at least 6 minutes, with good pointing (an arcminute, repeatably), and the ability to reach 14th magnitude with good signal in less than 1 minute. An aperture of at least 8" is required. Students will need to know or be able to determine the platescale (arcsec/pix) of their images. An astronomical CCD (not a consumer digital camera) is also required. Students must have their equipment inhand, setup, and tested before taking on this project!
Project 2: Radio Trends: Optically Identifying 20cm sources (Data Provided) Supervisor: Pamela Gay Outline:
Astronomers use radio sources to identify areas where they hope to find young stars, galaxies with star formation, and galaxies with active galactic nuclei. In this project, students will compare the morphology the brightest 20 radio sources within 30 degrees of the North Galactic Pole with the brightest 20 radio sources within +/- 10 degrees of the Galactic Equator. Students will use the New VLA Sky Survey (NVSS) to determine their object lists and use optical data from the Digital Sky Survey to visually identify the source of the radio emission. Final projects should discuss:
- How radio sources are optically identified and what concerns must be addressed,
- The source of optical and radio emission in the project's objects, and how this effects the objects' apparent morphologies in each waveband, and
- The differences in bright radio source populations in the two regions.
Project 3: The right optics for the job: comparing telescopes Supervisor:Pamela Gay Outline:
Looking around the astronomical community, one finds telescopes in all shapes and sizes, with instruments mounted at a large variety of focal points. Each configuration has specific advantages and disadvantages. In this project, students are asked to compare four distinct telescope designs of their choice, discussing the instrument possibilities (specta/imaging) for each design and typical optical advantages and disadvantages. Students are expected to provide historical and/or modern examples of how each design has been used to make significant discoveries. Final projects should discuss/include:
- Definitions of coma, astigmatism, field distortion, spherical aberration and chromatic aberration, as well as Coude?, Cassegrain, and prime focus.
- Accurate, properly scaled, light-ray diagrams for each design discussed,
- Discussion of ideal uses/instrumentation for each, accounting for FoV, f/ratio, optical aberrations, etc, and
- Professional examples of each design, why it was chosen, and how it succeeded.
Students may need software for drawing their diagrams. While CAD software is recommended, any vector drawing software (like Adobe Illustrator) can be made to work. Hand drawn scanned diagrams will also be fine. Students must have their software installed and be familiar with its use before taking on this project!
Project 4: Instrumental Options: Catching the right wave Supervisor:Pamela Gay Outline:
In our modern digital age astronomical observations are made with digital sensors and receivers using computers in partnership with old-fashioned lenses, horns and grisms/prisms. Exactly what technology should be used varies with the wavelength being observed for a variety of reasons, ranging from the energy sensitivities of various materials and the needed thermal cooling and noise isolation. in this project students will be expected to compare four different instrumentation technologies of their choice, discussing the wavelength sensitivities, spatial/spectral resolutions, and configuration options. Selected instrumentation should include at least one example used for spectroscopy, and two different passbands (e.g. radio, far IR, Near-IR/Optical/UV, far-UV, gamma-ray, or x-ray). To receive high marks students should discuss the historical development of the instrument, professional example(s) and their (its) discoveries, and what telescope/focus is needed to compliment the instrument. Possible choices include, but are not limited to: Fabry-Perot Spectral Imaging detectors, CCDs, CMOS detectors, X-ray imaging with coded masks, high-speed multi-channel photo-multipliers, Fourier Transform Spectrographs, multi-slit fiber-fed spectrographs, and Cherenkov imaging.
Project 5: Astroimaging vs Astrophotography (observing) Supervisor:Pamela Gay Outline:
Even in today's era of cheap digital cameras and dropping CCD prices, many astronomers continue to reach for film and glass plates. In this project, students will compare CCD and film images taken of the same objects with the same final exposure time and same telescope. Students are expected to observe one Landolt standard field and obtain a deep image of one "pretty" field containing nebulosity or a high-contrast large galaxy. (Landolt standards are standard star fields compiled by Arno Landolt over many years, and are typically known as "E region" or SA fields.) Final projects should discuss/include:
- Differences in linearity, sensitivity, resolution, and dynamic range in film and CCD images,
- Differences in setup complexity (e.g. sensitizing film, cooling CCD, etc),
- Differences in reduction/analysis complexity, and
- When it is best to use either of these imaging methods.
Students need a telescope, CCD, and manual camera with proper adaptors. Students must have their equipment inhand, setup, and tested before taking on this project!
Project 6: Filtering the Sky (observing) Supervisor:Pamela Gay Outline:
Filters are used in many astrophotographic applications such as the observation of the Sun, planets, stellar classification or nebulae etc... Filters form two basic types. The first is a broad band filter usually made from a transparent material with the addition of dyes and the second is a very narrow band filter made from thin layers of vacuum deposited material called an interference filter. In this project, students will demonstrate how filters are used to get specific information on objects by making their own observations using 2 or more filters. Final projects should discuss/include:
- The different types of filters used, their construction, and examples of their use,
- Why the field observed was selected,
- Why the filters used were selected,
- The science derived from the filtered images.
Students need filters, a telescope, and a CCD or manual camera with proper adaptors. Appropriate data reduction software is also required for CCD observations. Students must have their equipment inhand, setup, and tested before taking on this project!
Project 7: Photometry: Sorting stars and galaxies Supervisor:Pamela Gay Outline:
The human eye does not always produce consistent results. For this reason, and because of the magnificent volume of data available, it is necessary to create software to automatically distinguish stars form galaxies in optical surveys. For this project, students will be using photometry software of their choice to find out the FWHM, ellipticity, and position angles of objects in Sloan Digital Sky Survey data. Using this information, they will write software (C, C++ or FORTRAN or another language as appropriate) to sort galaxies from stars. Final projects should discuss:
- How the profiles of stars and galaxies differ,
- What real effects cause galaxies and stars to be mis-classified,
- What optical problems/distortions must be considered before believing results,
- How well the software worked against an open cluster and a Zwicky cluster.
Students will need photometry software and a software compiler. IRAF, MIRA, MaximDL or CCDsoft will work best, although other software programs can also produce good results. A GNU compiler is recommended, but not required. Students must have their software installed and be familiar with its use before taking on this project! Also note that this project is quite difficult!!
Project 8: Variable Star Observations: Mode Sorting (observing) Supervisor:Pamela Gay Outline:
Pulsating variables, such as RR Lyrae stars, vary in brightness with specific modes. Most RR Lyrae stars have one pulsation mode, and when observed have consistently repeating light curves with little scatter. Some RR Lyraes and many delta Scuti stars, however, have complicated periods, demonstrating either modulation of the primary mode (e.g. the Blazhko effect) or multiple modes beating against each other. In this project, students will observe an RR Lyrae or delti Scuti star with either type of these complicated periods, and then solve for the periods. Final projects should discuss/include:
- A definition of the type of multi-periodicity being observed and its possible cause,
- Differential photometry, and
- The technique used to de-scramble the periods.
Students need a telescope + CCD with the ability to reach 14th magnitude with good signal in less than 1 minute. Students will need to be able to do differential photometry. Students must have their equipment inhand, setup, and tested before taking on this project!
Project 9: Variable Stars - Data Mined Supervisor: Pamela Gay Aim:
To explore and understand different variable stars Overview:
Using data from the AAVSO's International Database, determine the period stability and evolution of at least 5 different intrinsic variable stars of the same type (ex. Mira, RR Lyrae, delta Scuti). Selected stars must have data covering a minimum of 10 years or 50 cycles, which ever is longer. To receive high marks, students must discuss their stars observed behavior in the context of what is expected from a literature review.
Project 10: Own Project If you wish to propose your own project you must first negotiate it with the unit instructor, Dr Pamela Gay. Note that your project topic cannot be approved unless the unit instructor agrees with it and we can find a suitable project supervisor.