Active & Experiential Learning with Low-cost Telescopes

Project Lead: I. Song

At first, students are attracted to astronomy mainly because of the awes and beauties of celestial objects. However, students rarely have opportunities to see celestial objects with their eyes using telescopes even if they take astronomy courses. Even for astronomy majors, course activities using a telescope are greatly limited because of (1) using the department-owned, centralized large telescopes, (2) the need for night-time gathering at the campus for astronomical observations, and (3) weather limitations including the light pollution at the campus site. Traditionally, night-time observations are done with expensive telescopes (8 inches to 14 inches in size with a price tag of up to a few thousand dollars) owned by the department, and such observations require students to be gathered at a campus at night which can cause a security issue. Ability to deploy a telescope to an individual student or a small (N<3) group of students can alleviate these problems.

With the advance of relevant technology & manufacturing, good quality optics become cheap and a very low-cost telescope (under \$100, e.g., Celestron's Firstscope Telescope) is readily available currently. In addition, one can build a small (~11 cm primary mirror) reflecting telescope from parts (mirrors, focuser, eyepieces, other material) and the total cost of such a DIY telescope is about \$100 per telescope. The DIY telescope can have many “teachable” moments.

We can develop several active-learning and experiential learning opportunities by using low-cost telescopes or DIY telescopes.

  • Create a new course, e.g., “Observational Astronomy II”, to be offered as an elective for astrophysics majors. This course will provide two active learning activities: (1) build a DIY telescope using components and (2) carry out an astronomical observation project using the telescope built in the first half of the semester.
  • First-Year Odyssey Seminar (FYOS) scourses: (1) we can offer an astrophotography class using a commercial low-cost telescope during a fall semester and (2) a course during a spring semester tailored toward the creation/usage of a DIY telescope.
  • PHYS 1252 / Advanced Lab: (1) Using optics parts, machine shop prepared materials, and 3-D printed parts → make a telescope, (2) create a spectroscope (using a simple grating), (3) use a smartphone as a camera or add a lost-cost CCD with relevant electronics, (4) obtain and measure gas emission lines to calibrate the spectroscope, (5) carry out a simple, astronomical photometric and/or spectroscopic observation project.
  • Dylan Valin (department's lab specialist) agrees to join as a team member, and he can mentor “assembly of telescope” activities including (1) 3-D printing of parts, (2) CNC milling of base plates, etc. Small Satellite Research Lab (SSRL) in the basement of the Physics building has a CNC milling machine and we may be able to use it through a contract.
  • Check the following site for manufacturing a telescope using cheap optics parts (mirrors etc.) and 3-D printed components: https://www.printables.com/model/224383-astronomical-telescope-hadley-an-easy-assembly-hig

To use a smartphone as a digital detector for astronomical observations, we need a special camera app that allows a much longer exposure time than possible. Use one of the following apps depending on your phone type.

Things to consider It would be beneficial to adopt a similar approach to the one showcased in the poster below when it comes to sharing lab instructions with students. Not only does this method help us utilize lab time more efficiently, but it also ensures that instructions are delivered clearly to students. Additionally, it presents an excellent opportunity for TAs to practice science communication skills. NJW had implemented this approach in his PHYS 1251/52 courses, and it was proven to be very effective.

DIY telescopes & Digital Detectors

Parts

  • Mirrors: \$29
  • Eye pieces (x3): \$29
  • DIY Focuser: here
  • Other materials (from hardware stores and 3D printing): ~\$20?

Low-Cost Digital Detector

As a start, we can use the smartphone as a digital detector. However, controlling the phone in terms of image output (full-frame, subsampling, well-depth, etc.) is greatly limited. We can build a DIY digital detector using a low-cost CMOS image sensor (e.g., OV2640 [\$9.99 in Amazon]) controlled by an Arduino ESP32 (three for \$15.99 in Amazon). However, this may require in-depth knowledge of electronics. We can build a course aiming to develop such a digital imaging detector (ASTR 3020?). In addition, we can also consider manufacturing a DIY spectrograph. There is a GitHub repo for controlling ESP32 camera board: ESP32 Camera Control

Alternatively, we can use an eyepiece camera that can be attached over the eyepiece and images can be captured through wifi-connected smartphones. It is listed at \$73 in amazon (search for “WiFi Telescope Eyepiece Camera” on Amazon).

Lab Topics suitable with Low-Cost Telescopes

  1. Observations of short-period variables (Cepheids, Eclipsing binaries, etc.) → recover known periods. Can be done on non-photometric nights
  2. Phase of the Moon → Specifics of scientific activities? Can be done on non-photometric nights
  3. Phase of Venus → Specifics of scientific activities? Can be done on non-photometric nights
  4. Color-Magnitude diagram of bright, nearby clusters (Pleiades, Hyades, etc.) → Need photometric nights
  5. Astrophotography → any significant scientific gains?
  6. Post Image processing (by Marni Shindelman)

Status of the Project

— Inseok Song 2024/05/03 15:36

  • Check this page for the progress made by an undergraduate team member, Anna Dmitrieff, using the FirstScope from Celestron.