Photometric Statistics
About Differential Photometry
Differential photometry removes common-mode variations by dividing target star flux by comparison star(s). Systematics from airmass, atmospheric transparency, and instrumental variations affect all stars equally.
Key Formula: Δm = -2.5 log(F_target / F_comp)
This technique improves precision from ~1-5% (absolute photometry) to 0.1-1% (mmag level), making it essential for exoplanet transit detection and variable star studies.
Instructions
- Target star (blue) has both systematics and a transit signal
- Comparison star (green) has same systematics but no transit
- Differential magnitude removes systematics, revealing the transit
- Increase systematics to see how differential photometry handles larger variations
- Adjust noise to see detection limits