Astronomical Optics

Course objectives

GENERAL OBJECTIVES: The course aims to describe the basics of optics for application of sky observations. At the end of the course, students will gain a deep knowledge of the impact of aberrations and diffraction in the final performance of a telescope by a quantitative evaluation. Students will be able to put into practice what they have learned during the course by working in teams by using an optical design and optimization commercial program. SPECIFIC OBJECTIVES: A - Knowledge and understanding OF 1) To know and to strengthen the basics of geometrical, physical and gaussian optics. OF 2) To understand how to recover and to quantify the defects present in telescope’s images and how to treat them. OF 3) To know the main figures of merit to compare and to evaluate between them different instruments. B - Application skills OF 4) To be able to apply what has been acquired by drawing, optimising and analysing the performance of a chosen telescope with the academic licence of one of the most used optics code. OF 5) To be able to work in a team by sharing the activities, search of data and analysis. D - Communication skills OF 7) To know how to communicate the main logical steps of their study and how it has been faced by reporting to the other students the results. E - Ability to learn OF 8) Have the ability to consult web sites and papers to integrate what has been learned during the course and to recover all the necessary information to study an optical instrument. OF 9) Have the ability to evaluate autonomously the performane of one specific optical instrument.

Channel 1
MARCO DE PETRIS Lecturers' profile

Program - Frequency - Exams

Course program
Part 1 – Basics Geometrical optics and third-order primary ray and wavefront aberrations, mono and chromatic. Aberrations correction solutions. Part 2 - Telescopes Classical configurations of reflective telescopes (Cassegrain, Gregorian, Ritchey-Chretien and Dall-Kircham), refractive (Galileian and Keplerian) and catadioptrics (Schmidt) and auxiliary optics. Description of a few of the current operating telescopes. Mounts with several rotation axes and corrective models for pointing systems. Liquid mirror telescopes. Part 3 – Diffraction and figures of merit Basics of diffraction in the case of optics with variable apertures and apodization. Study of a few figures of merit (PSF, EE, OTF) and their application. A peculira case: analysis of the Hubble Space Telescope. Part 4 – Optical design Introduction at a dedicated software and applications on existing telescopes. Work in teams to study the performance of different chosen telescope. Part 5 - Gaussian Optics or Quasioptical systems Gaussian beam propagation; Matrix approach; Beam transformation by a thin lens; Gaussian Beam coupling; Corrugated horns. Part 6 - Atmosphere Atmospheric impact on observations from the ground in terms of stability and fluctuations. Conditioning of the Earth's atmosphere on the choice of sites and on the astronomical optics design at different wavelengths: atmospheric refraction and seeing (VIS-IR) and sky-noise (mm). Atmospheric parameters to quantify its variability (Fried, coherent time and isoplanatic angle). Part 7 - Adaptive and Active optics Basics and application, wavefront correctors, wavefront sensors and artificial stars. Part 8 – Different optics in Astronomy Gamma telescopes: coded masks and Compton telescopes. X-ray telescopes: configurations. Solar towers, mm-telescopes [optical solutions for spatial modulation], radiotelescopes and radio interferometers.
Prerequisites
a) A fundamental prerequisite is that the students must have the knowledge of physics and optics requested by the first level University degree in Physics or in Astronomy and Astrophysics. b) It is important that students have basic knowledge of Astronomy and Astrophysics. c) It is useful to be familiar with the use of computers and a programming language.
Books
1 - Lecture Notes of the course "Ottica Applicata" by M. De Petris (http://oberon.roma1.infn.it/otticaastronomica) 2 - F.A. Jenkins e H.E. White "Fundamentals of Optics", McGraw-Hill Inc. 1981 3 - D.J. Schroeder "Astronomical Optics", Academic Press, (522 Sch - Rif Biblio Dip. Fisica) 4 - P.F. Goldsmith "Quasioptical Systems" IEEE Press (621 38 Golds - Rif Biblio Dip. Fisica) 5 – papers as referred during the lessons.
Teaching mode
The lecture format is through blackboard and slide presentation. Over and above the lectures, the students, in a team, will take part in a programme in optical design to study the optical performance of a current observing telescope. This will be arranged beforehand with the course professor. The final analysis will be presented in the lecture hall near the end of the course.
Frequency
The student is not obliged to attend the lessons but in that case it is suggested to contact the professor.
Exam mode
The final exam consists in an oral discussion exam (almost 40 minutes) where the candidate has to present an in-depth analysis on one of the course topics, previously agreed upon with the professor. A few questions on the full course programme will complete the exam. The student will be asked to apply the methods learned during the course to exercises or to examples and situations similar to those that were discussed in the course. The evaluation takes into account: - Correctness and completeness of the concepts discussed by the student; - clarity and rigor of presentation; - analytical development of the theory; - problem-solving skills (method and results).
Lesson mode
The lecture format is through blackboard and slide presentation. Over and above the lectures, the students, in a team, will take part in a programme in optical design to study the optical performance of a current observing telescope. This will be arranged beforehand with the course professor. The final analysis will be presented in the lecture hall near the end of the course.
  • Lesson code10620436
  • Academic year2025/2026
  • CourseAstrophysics and Cosmology
  • CurriculumSingle curriculum
  • Year1st year
  • Semester2nd semester
  • SSDFIS/05
  • CFU6