Measuring a meteor shower
The question
How does the rate of a meteor shower change from night to night around its peak?
Each shower happens when the Earth crosses a stream of dust left by a comet. Counting meteors carefully, and noting how dark the sky is, lets observers compare nights fairly.
Equipment
- An adult
- A reclining chair, warm clothes and a red torch
- A watch, a recording sheet and a star chart of the shower's radiant
Method
- Choose a shower and observe for one hour on three or more nights around its peak, at the same time each night.
- For each meteor, note the time and whether it came from the radiant (a shower meteor) or not (a sporadic).
- Record cloud and the faintest star you can see, which tells you how dark the sky is.
- Work out the number of shower meteors per hour each night.
- What to measure
- Shower meteors and sporadic meteors per hour, the faintest star visible, and the radiant's height.
- How to present it
- A graph of meteors per hour against date, with the expected peak marked, and a discussion of how moonlight and cloud affected your counts.
- Take it further
- Find out what the zenithal hourly rate is and why your count is almost always lower.
Safety
Always with an adult. Keep away from roads, water and cliff edges, and dress for the cold.