Use a telescope to observe the triple star system 40 Eridani, whose coordinates are R.A. = 4 h 15.3m and Dec. = 7° 39’. The primary, a 4.4-magnitude yellowish star like the Sun, has a 9.6-magnitude...

Use a telescope to observe the triple star system 40 Eridani, whose coordinates are R.A. = 4^h
15.3m and Dec. = 7° 39’. The primary, a 4.4-magnitude yellowish star like the Sun, has a 9.6-magnitude white dwarf companion, the most easily seen white dwarf in the sky. On a clear, dark night with a moderately large telescope, you should also see that the white dwarf has an 11th-magnitude companion, which completes this interesting trio.