54 Leonis (Struve 1487) -- Double Star in Leo
Yellow & Blue Double-Star in the Lion
With a yellowish primary and a bluish secondary, the double-star 54 Leonis (Struve 1487) is
a lovely sight. It is a perfect way to end a long night’s observing session; bright, colorful and
easy to draw. The double-star rests on the border of Leo and Leo Minor. 54 Leonis, at
magnitude 4.5, is on the edge of visibility, on the best of nights, from my suburban backyard.
This was one of those nights. With a separation of 6.6 arcseconds it was an easy split in both
the 155mm refractor and the 60mm refractor but seeing the color of the twin stars was only
doable in the larger refractor.
I always try and end an observing session with something that is not observationally
demanding. This, to me, is like cooling-down from exercising. It softens the experience of
the observing period and ends it on a success. Often it is a double-star that meets my needs.
One additional note. You will notice that the Spectral Type of the secondary star ends with a
small “n”. This stands for “nebulous lines” in its spectrum and is caused by the extremely rapid
rotation of the star.