This Week’s Sky at a Glance, 2026 March 14 – March 21
This Week’s Sky at a Glance, 2026 March 14 – March 21
With Tuesday being party time for many O’Revelers, is there anything green that we can see in the sky? Yes, but rarely. We can see stars that are red, orange, yellow, blue or white, but not green. The colours are representative of their outer temperature, with red being coolest and blue the hottest. Any star with an outer temperature corresponding to green, which is in the middle wavelengths of the visible spectrum, emits approximately equal but lesser amounts of red and blue light. This combination gives us white light. Our Sun’s outer temperature of 5500 C puts it just on the green side of yellow.
Some stargazers have claimed to see green stars that are part of a binary pair with a red giant star. Green is the complementary colour of red, and it is thought that if you observe a white star after staring at a red one, the complementary after-image can make the white star look green. It is said that Zubeneshamali, the brightest star in Libra and the one with the longest common name, is green. I did see it once as a very pale green in an 8-inch telescope, but that might have been due to the power of suggestion. Uranus usually looks pale green in a backyard telescope.
The most common reason for green in the sky, although still fairly rare in New Brunswick, is the northern lights. Energetic electrons from the Sun (aka Sol, the shortest name for a star) can make oxygen atoms in our upper atmosphere emit green light in a manner similar to that of a neon light. Northern lights are seen more frequently around the equinoxes, and if electrons in the solar wind have escaped the Sun through flares or holes in its magnetic field lines, we could get lucky this week. If not, then take a break from partying to look up at the constellation O’Ryan.
This Week in the Solar System
Saturday’s sunrise is at 7:38 and sunset will occur at 7:28, giving 11 hours, 50 minutes of daylight. Next Saturday the Sun will rise at 7:25 and set at 7:38, giving 12 hours, 13 minutes of daylight. Next Friday at 11:46 am the Sun crosses the equator to mark the beginning of spring in the northern hemisphere.
The thin crescent Moon makes a triangle with Mercury and Mars Tuesday morning but the shallow angle of the ecliptic places them less than 5 degrees (a typical binocular view) higher than the Sun and unobservable. The Moon is new the following day. On Thursday evening, those who enjoy a challenge can try to see the razor-thin crescent of a 22-hour Moon just over a binocular-width to the lower right of Venus. By Friday evening it will be the same distance above Venus. On Sunday evening telescope users might see Jupiter’s moon Ganymede disappear behind the planet at 7:59 and reappear at 11:17. Saturn is lost in bright twilight as it moves toward conjunction the following week.
Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel or Facebook page of Astronomy by the Bay.