From the July 2008 issue

The ups and downs of a variable star

X Cygni and a handful of the Swan's residents provide additional challenges for September binocular observers.
By | Published: July 25, 2008 | Last updated on May 18, 2023
The well-known Cepheid variable star X Cygni lies on the eastern edge of open cluster Ruprecht 173, which is discussed in this month’s print column.