# Delta Cephei: Worksheet

 Fall 2005 ASTR 110L, Sec. 2 Name: ________________

Use this worksheet to record your estimates of the magnitude of the variable star delta Cephei. Remember that you should make at least 12 observations over the course of the semester for full credit; some of these observations can be made during class, but others you must make on your own.

 Obs. Date/Time Estimate #1 Estimate #2 Estimate #3 Average 1. 10/05 @ 21:00 3.6 none none 3.6 2. ____________ ____________ ____________ ____________ ________________ 3. ____________ ____________ ____________ ____________ ________________ 4. ____________ ____________ ____________ ____________ ________________ 5. ____________ ____________ ____________ ____________ ________________ 6. ____________ ____________ ____________ ____________ ________________ 7. ____________ ____________ ____________ ____________ ________________ 8. ____________ ____________ ____________ ____________ ________________ 9. ____________ ____________ ____________ ____________ ________________ 10. ____________ ____________ ____________ ____________ ________________ 11. ____________ ____________ ____________ ____________ ________________ 12. ____________ ____________ ____________ ____________ ________________ 13. ____________ ____________ ____________ ____________ ________________ 14. ____________ ____________ ____________ ____________ ________________ 15. ____________ ____________ ____________ ____________ ________________ 16. ____________ ____________ ____________ ____________ ________________

### Instructions

• Remember that magnitudes are backwards; fainter stars have larger magnitudes!
• delta Cephei varies between about magnitude 3.5 at its brightest to magnitude 4.4 at its faintest.
• Convenient comparison stars are zeta Cephei, magnitude 3.6, and epsilon Cephei, magnitude 4.2.
• Record the date and time of each observation -- without them, you won't be able to plot your data!
• Make three independent estimates of delta Cephei's magnitude, and write them down in the table.
• Later, take the average of the three estimates you made, and write that in the final column.