10762 - Astronomical Optics

Learning outcomes

Provide the student with a basic knowledge of geometrical and wave optics, with specific application to astronomical instrumentation and observations. Provide the student with the capability of evaluating the performances of simple optical systems.

Course contents

Recommended prerequisites: a working knowledge of basic physics (mechanics, waves, electromagnetism) and mathematics (differential and integral calculus, linear algebra, complex numbers, trigonometry).

The course carries a total of 7 ECTS credits, of which 5 are devoted to lectures and 2 to laboratory activities. The lectures are organised into three distinct but complementary modules.

1. Lecture contents

Module 1 – Geometrical optics

Nature of light and introduction to electromagnetic radiation; fundamental phenomena (reflection, refraction, absorption, dispersion); atmospheric effects on astronomical observations (atmospheric refraction, absorption); prisms and plane-parallel plates; mirrors and thin lenses; the eye as an optical system; optical aberrations (chromatic, spherical, astigmatism, coma, distortion).

Module 2 – Wave optics

Polarisation of light; Huygens–Fresnel principle; interference; diffraction; diffraction grating; optical Fourier transform and spatial filtering; resolving power of optical instruments, point spread function (PSF), sampling.

Module 3 – Optics applied to astronomy

Analytical treatment of atmospheric turbulence; optical configurations in astronomical telescopes; overview of modern telescopes (optical, X-ray and radio); ground-based and space telescopes.

2. Laboratory activities

The laboratory component comprises three hands-on experiments carried out in small groups:

• Measurement of converging, diverging and coupled lenses
• Michelson interferometer and analysis of interference fringes
• Image formation and optical Fourier transform

3. Experimental demonstrations

The course includes two demonstration sessions with active student participation, covering the following topics:

• Polarisation of light and Malus's law (data acquisition and analysis)
• Use of a diffraction grating and spectrograph
• Visualisation of atmospheric turbulence and its effects on the PSF

4. Visit to the Cassini telescope at Loiano

Subject to availability, the course may include a visit to the Cassini telescope at the Loiano Observatory, with daytime solar observation and evening use of the 1.5-metre telescope for professional-level astronomical observations. Should an on-site visit not be feasible, an online link-up with the Observatory may be arranged instead. Details and scheduling will be communicated during the course.

 

Readings/Bibliography

Material required for exam preparation

All material needed to prepare for the course and the exam is available on the University's Virtuale platform. The material includes:

• Lecture slides covering the theoretical content presented in class;
• Jupyter Notebooks with Python code examples, guided exercises and hands-on applications of key concepts (polarisation, interference, diffraction);
• Detailed instructions for the proposed laboratory activities.

The material is organised by thematic units, aligned with the modules of the syllabus, and is updated regularly throughout the course.

Recommended texts for further study

No textbook purchase is required. However, students wishing to deepen their understanding of the topics covered may consult:

• Eugene Hecht, Optics, Addison-Wesley – a comprehensive and authoritative reference on optics.
• Mencuccini, Silvestrini, Fisica – Elettromagnetismo e Ottica, Casa Editrice Ambrosiana.
• Mazzoldi, Nigro, Voci, Fisica Vol. II, EdiSES, 2019.
• Mazzoldi, Paolo, Fisica Vol. II, EdiSES, 2021.

Note for non-attending students: access to the Virtuale platform is strongly recommended, as it also contains any updates and announcements from the instructor.

Teaching methods

The course comprises lectures, laboratory activities, experimental demonstrations and an observing visit to the Cassini telescope at Loiano.

1. Lectures (in person)

The lectures introduce and develop the core theoretical topics, supported by practical examples and simulations.

2. Laboratory activities (in person)

The laboratory sessions are carried out in small groups in order to foster peer collaboration, develop theoretical and practical problem-solving skills, and put into practice the concepts covered in class.

Given the nature of the activities and the teaching methods adopted, attendance of this course requires all students to complete safety training modules 1 and 2 in e-learning mode and to attend module 3 of specific training on health and safety in study environments. Information on dates and attendance arrangements for module 3 can be found in the relevant section of the degree programme website.

3. Demonstrations

During the demonstration sessions, led by the instructors, students are actively involved in observing and interpreting physical phenomena. These sessions promote critical thinking, hypothesis formulation and collaborative problem-solving.

4. Visit to the Cassini telescope at Loiano

The course includes a visit to the Cassini telescope at the Loiano Observatory. The experience comprises daytime solar observation and evening use of the 1.5-metre telescope for professional-level astronomical observations.

Assessment methods

The assessment consists of an individual oral examination designed to evaluate, in an integrated manner, theoretical knowledge, practical skills and transversal competences, in line with the learning objectives of the course. The examination is divided into two consecutive parts. The grade may be rejected a maximum of two times.

1. Individual presentation on laboratory work (25% of the final grade)

Each student prepares a short oral presentation (maximum 5 minutes, supported by slides in PPT/PDF format) on a topic of their own choice related to one of the three laboratory experiments carried out during the course. The topic is individual: each member of a laboratory group must choose a different aspect of the experiment, so as to ensure independent and non-overlapping preparation.

The presentation must include a component of critical analysis — for example, a discussion of error sources, a comparison between expected and measured results, or a reflection on the methodological choices made. At the end of the presentation, the instructor will ask brief follow-up questions (2–3 minutes) to verify the student's understanding of the underlying physical principles and the authenticity of the work presented.

The presentation must be uploaded to the Virtuale platform at least one week before the scheduled date of the oral examination. Timely submission of the presentation is a prerequisite for admission to the oral exam.

2. Theory questions (75% of the final grade, 25% each)

The student then answers three open-ended questions on the theoretical content covered in the three modules of the course. Each question lasts approximately ten minutes. The four components of the examination (presentation plus three theory questions) contribute equally to the final grade (25% each). The exam is conducted by the two course instructors in parallel, each examining a subset of students individually.

Final grade

The final grade is expressed on a scale of thirty. The grading criteria are as follows:

• 18–19: Very limited knowledge; understanding only with guidance from the instructor; purely descriptive laboratory presentation with no critical analysis; imprecise but acceptable use of language.
• 20–24: Partial knowledge; analysis limited to routine tasks; correct laboratory presentation but with underdeveloped reflection; generally correct use of language.
• 25–29: Solid and well-articulated knowledge; independent analysis; well-motivated laboratory presentation with good critical discussion; appropriate use of disciplinary terminology.
• 30–30L: Thorough and in-depth preparation; excellent ability to draw connections and construct arguments; original and well-structured laboratory presentation with in-depth critical analysis; precise and effective use of language.

Attendance

Attendance at lectures is strongly recommended, while attendance at laboratory sessions is mandatory. In the case of justified impediments (e.g. working students), flexible arrangements may be agreed with the instructors. Students in this situation are advised to contact the instructors well in advance to allow adequate reorganisation of activities.

Use of generative Artificial Intelligence (AI)

With regard to the assessment, limited, declared and non-substantial use of AI for support activities (e.g. summarising or rephrasing) is permitted during the preparation of the laboratory presentation. Substantial use of AI to generate the content of the presentation is not allowed. The student's actual individual contribution will be verified through follow-up questions during the oral examination.

Students with specific learning disabilities (SLD) or disabilities

Students with SLD or temporary or permanent disabilities are advised to contact the relevant University office in good time at https://site.unibo.it/studenti-con-disabilita-e-dsa/it. The office will propose any appropriate accommodations to the students concerned; these must be submitted for approval to the course instructor at least 15 days in advance, and the instructor will assess their suitability in relation to the learning objectives of the course.

Teaching tools

• Video projector and whiteboard for lectures
• Virtuale [https://virtuale.unibo.it/my/] platform for distributing slides, notebooks and teaching materials
• Jupyter Notebooks with Python simulations for the analysis of optical phenomena
• Optical bench and laboratory equipment (laser, lenses, interferometer, gratings)
• Cassini telescope at the Loiano Observatory
• Spectrograph and polarisation demonstration kit

All materials are available in accessible formats. Accommodations for students with disabilities are provided upon request.

Office hours

See the website of Carmela Lardo

See the website of Gabriele Umbriaco

See the website of Bruno Marano