Skip to content

Exoplanet transit

Canonical version: Exoplanet Science — Complete.md This note preserved — good practical checklist and software workflow content.

This is one of the most scientifically valuable contributions an amateur astronomer can make. Professional surveys like TESS (Transiting Exoplanet Survey Satellite) scan the entire sky to find potential planets ("candidates"), but they often lack the time or resolution to verify them.

That is where you come in. Using high-end amateur gear, you can perform Transit Photometry—measuring the tiny dip in brightness of a star as a planet crosses (transits) in front of it.1

Here is a guide to the equipment, techniques, and workflows required to transition from taking pretty pictures to gathering scientific data.

4. Software & Workflow

Phase Software Examples Purpose
Planning Swarthmore Transit Finder, NASA Exoplanet Archive Tells you when a transit will occur visible from your location.
Capture N.I.N.A., SGP, MaximDL Automates the imaging sequence.
Analysis AstroImageJ (AIJ) The industry standard for amateur photometry. It performs the differential photometry and generates the light curve.

Pro Tip: When planning, always aim to capture 1 hour before the transit starts and 1 hour after it ends. This "baseline" data proves that the star was stable before the dip occurred.

5. How to Submit Your Data

Once you have a light curve, where does it go?

  1. NASA's Exoplanet Watch: The best place to start. They have a very user-friendly pipeline (EXOTIC) that can even process the data for you if you struggle with AstroImageJ.
  2. AAVSO (American Association of Variable Star Observers): They have an Exoplanet Database (EOD) where you can upload your observations.4
  3. TFOP (TESS Follow-up Observing Program): This is the "big leagues" for amateurs. You usually need to demonstrate high competence in the groups above before joining TFOP SG1 (Sub Group 1) to verify official TESS candidates.

Summary Checklist for Tonight

  • [ ] Target selected: (Is it high enough in the sky? Will it transit during darkness?)
  • [ ] Time Synced: PC clock updated to UTC.
  • [ ] Guiding: Calibrated and running.
  • [ ] Focus: Slightly defocused (donut shape).
  • [ ] Cadence: Exposures set so the star is at roughly 60-70% saturation (ADU).

Would you like me to help you find a suitable exoplanet target transiting tonight based on your telescope size and location?