‘Star of Bethlehem’ visible in evening sky this week

Jupiter and Venus appear to be less than a fingernail width apart in the evening sky this week, outshining the normally resplendent Regulus star, said Merrimack College Physics Department adjunct professor Ralph Pass who runs the school's observatory.

On June 30 the planets aligned to within one-third a degree to each other and will remain within 2 degrees of each other through July 4.

“What is extraordinary is how close Jupiter and Venus are, or how close they were, a couple days ago,” Pass said July 2. “They were about one-third of a degree, which is about two-thirds the diameter of the moon in the sky. One-third degree is about half the width of a finger nail.”

Some astronomers believe the alignment of Venus and Jupiter may have been the basis of the Star of Bethlehem.

Regulus, in the Leo constellation, is 79 light years away and normally the brightest star in the sky.

Even though the planets appear close they are millions of miles away from each other. Venus is 58 million miles from Earth and Jupiter is 565 million miles, according to CBS News.

They won’t align so closely again until August 2016 when they appear .06-degree separation, Pass said.

“You’ll have trouble telling them apart,” Pass said.

The fun isn’t over for the summer. The Perseid meteor shower is expected Aug. 13.

NASA’s flyby of Pluto is expected July 14, Pass said.

“It’s not something you can see with your naked eye; it is something you can be aware of in space,” he said.

Jupiter and Venus will align within 1 degree Oct. 25 this fall so it won’t appear as spectacular as this week’s alignment.

The Mendel Observatory is staffed by volunteers and open to the public during the

summer Wednesdays from 9 to 10 p.m. The weather permitting line is 978-837-5011.