Astronomy EssentialsSpace

Sun in zodiac constellations, 2018

Zodiac constellations: Old man in Grecian garb holding a long writhing snake, with stars scattered around.
Ophiuchus the Serpent Bearer is not an astrological sign, but it is one of the 13 zodiac constellations. In 2018, the sun crosses into Ophiuchus on November 30. Image via Wikipedia.

Zodiac constellations vs. zodiac signs

You might know that the real sun in the real sky does not appear in front of a constellation of the zodiac within the same range of dates you’ll see listed in astrological horoscopes. That’s because astrology and astronomy are different systems. Astrologers typically indicate the sun’s position with signs while astronomers use constellations. We were asked for:

… a list of the constellations that fall on the ecliptic with the exact degrees.

And we’ve located this information in Guy Ottewell’s Timetable of astronomical events. Below, you’ll find the dates for the sun’s entry into each zodiacal constellation during the year 2018, plus the sun’s ecliptic longitude – its position east of the March equinox point on the ecliptic – for each given date.

We are using the boundaries for the zodiacal constellations established by the International Astronomical Union in the 1930s.

Image courtesy of Wikipedia
The sun resides at a longitude of 0o on the ecliptic at the March equinox. The sun is at 90o ecliptic longitude at the June solstice, 180 o ecliptic longitude at the September equinox and 270o ecliptic longitude on the December solstice. Image via Wikipedia

Dates of sun’s entry into zodiac constellations

Date of sun’s entry into each zodiacal constellation (and corresponding ecliptic longitude):

Dec 18, 2017: Sun enters constellation Sagittarius (266.59o)

Jan 19, 2018: Sun enters constellation Capricornus (299.71o)

Feb 16, 2018: Sun enters constellation Aquarius (327.88o)

Mar 12, 2018: Sun enters constellation Pisces (351.57o)

Apr 19, 2018: Sun enters constellation Aries (29.08o)

May 14, 2018: Sun enters constellation Taurus (53.46o)

Jun 21, 2018: Sun enters constellation Gemini (90.43o)

Jul 21, 2018: Sun enters constellation Cancer (118.25o)

Aug 10, 2018: Sun enters constellation Leo (138.18o)

Sep 17, 2018: Sun enters constellation Virgo (174.15o)

Oct 31, 2018: Sun enters constellation Libra (217.80o)

Nov 23, 2018: Sun enters constellation Scorpius (241.14o)

Nov 30, 2018: Sun enters constellation Ophiuchus (248.03o)

Dec 18, 2018: Sun enters constellation Sagittarius (266.60o)

Source: Guy Ottewell’s Timetable of astronomical events

Spherical grid with central Earth, celestial equator, ecliptic, and ecliptic poles.
Earth-centered ecliptic coordinates as seen from outside the celestial sphere. Ecliptic longitude (red) is measured along the ecliptic from the vernal equinox at 0 degrees longitude. Ecliptic latitude (yellow) is measured perpendicular to the ecliptic. Image via Wikimedia Commons.

Zodiac constellations

Taurus? Here’s your constellation
Gemini? Here’s your constellation
Cancer? Here’s your constellation
Leo? Here’s your constellation
Virgo? Here’s your constellation
Libra? Here’s your constellation
Scorpius? Here’s your constellation
Sagittarius? Here’s your constellation
Capricornus? Here’s your constellation
Aquarius? Here’s your constellation
Pisces? Here’s your constellation
Aries? Here’s your constellation
Birthday late November to early December? Here’s your constellation

Colorful chart with astrological signs on left and constellations on right by month.
Dates of sun’s entry into astrological signs versus astronomical constellations. Chart and more explanation at Guy’s Ottewell’s blog. Used with permission.

Bottom line: Sun-entry dates to zodiac constellations in 2018, using boundaries for constellations set by the International Astronomical Union in the 1930s.

Sun’s entry into astrological signs of the zodiac

What is the zodiac?

January 12, 2018
Astronomy Essentials

Like what you read?
Subscribe and receive daily news delivered to your inbox.

Your email address will only be used for EarthSky content. Privacy Policy
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.

More from 

Bruce McClure

View All