Note: use a mouse instead of a trackpad or touchscreen to limit frustration while using Afterglow.
Click “Next” above to see the step-by-step instructions.
Alternate Format: Video Instructions
- Follow along with part of this tutorial video
Alternate Format: Written Instructions
- Return to the graphing website: https://skynet.unc.edu/ASTR101L/graph/
- Make sure everything is set up as it was at the end of Plotting Change in Brightness – Variable Star
- Click on “Periodogram”
- find the tallest peak, and record the x value (the period) that corresponds with that location in your assignment.
- Click on “Period Folding”
- Deselect “Show Two Periods
- Set “Period (days)” to the value you recorded from the periodogram in the previous step. This is how fast the variable star is pulsing.
- Adjust the period slightly up and down until the data points make a fairly smooth line.
- Give your graph a title and label the axes.
- We’re plotting magnitude (vertical axis) versus period-folded time (horizontal axis).
- Save and upload this graph to the assignment.
- Record the highest and lowest magnitudes from your period-folded graph on the assignment.
- Complete the calculations in the assignment.