Home > Ephemeris Program, Observing, Stars > 04/18/2022 – Ephemeris – Arcturus, the fourth-brightest nighttime star*

04/18/2022 – Ephemeris – Arcturus, the fourth-brightest nighttime star*

April 18, 2022

This is Ephemeris for Monday, April 18th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:31, and it will rise tomorrow at 6:51. The Moon, 2 days past full, will rise at 11:17 this evening.

The fourth-brightest nighttime star* is now up in the east these evenings. It is Arcturus, a bright star with an orange hue. It can be found otherwise by finding the Big Dipper and tracing out and extending the curve of the handle and saying the phrase “Follow the arc of the handle to Arcturus”, to remember the name of the star and how to find it. Arcturus is about 37 light years from us and is moving quite rapidly across the sky, compared to most stars, but one would not notice it to the naked eye in one’s lifetime. Arcturus is slightly more massive than our Sun, and about 7 billion years old, and is entering its red giant stage of life after using all the hydrogen fuel in its core. Our Sun, being slightly less massive, will survive on hydrogen a bit longer.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

*Or 5th brightest star, depending on which list you look at. Arcturus and Vega, which is just above the horizon in the northeast at 10 pm, are nearly the same brightness, however Vega is white while Arcturus is orange, making brightness comparisons difficult visually. Stellarium, however, reports Vega is a slightly brighter magnitude 0.00, while Arcturus is 0.15. My older lists say Arcturus is the 4th brightest star. I’m an older guy, so I’m sticking with it.

Addendum

How to find Arcturus nearly a month into spring. Arcturus is in the east in the evening. The Big Dipper is high in the northeast standing on its handle. To find and remember the name of this star, simply follow the arc of the handle to Arcturus. Created using Stellarium and GIMP.

I’ll have more tidbits about this remarkable star throughout the spring and summer. Can’t wait? Search for Arcturus on this blog.

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