BETHLEHEM, Pa. — Brad Klein reviews upcoming astronomical highlights with Bethlehem’s ‘Backyard Astronomy Guy,’ Marty McGuire.
This week provides one of the best chances of the year to spot the elusive planet, Mercury. That’s because Friday, July 4 marks the point of greatest eastern elongation for the innermost planet.
That’s astronomical jargon for the moment when a planet appears furthest from the sun, as seen from Earth. At Mercury’s greatest eastern elongation, it appears at its highest point above the western horizon just after sunset. And so it remains visible longer before setting.
“It doesn't set until just after 10 p.m.,” McGuire said. “So you've got a narrow window, looking to the west.”
Mercury is faint, and since it’s the innermost planet, only visible close to sunrise or sunset. So it presents a fun challenge to the stargazer, according to McGuire.
To view Mercury, it helps to have a pair of binoculars. And it’s absolutely necessary to have an unobstructed view of the western horizon.