Chi Cygni

Chi Cygni (χ Cyg / χ Cygni) is a variable star of the Mira type in the constellation Cygnus. Chi Cygni shows one of the largest variations in magnitude known. Typically it brightens and fades from 5th to 13th magnitude. The average period of this brightness fluctuation is 407 days. Observed extremes were 3.3 and 14.3 respectively. Thus Chi Cygni is visible at its minimum only with telescopes larger than 30 centimeters, while at maximum brightness is easily visible to the naked eye. Its distance is approximately 345 light years. The astronomer Gottfried Kirch discovered its variability in 1686.
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