The Celestial Sphere

by Matthew Johnson

With temperatures hovering between zero and 15 degrees for most of our Norfolk winter days and nights, the warmer weather that springtime brings will be a welcome event. The transition from winter to spring begins on March 20 at 11:33 a.m. with the long-awaited vernal equinox. On the equinox (from the Latin for “equal”), the earth in its orbit around the sun is exactly midway between winter at one extreme of the orbit and summer at the other extreme of the orbit, meaning we have an equal 12 hours each of daylight and night. On March 20, the sun will be directly over the equator and will rise higher every day after that, increasing daylight hours over nighttime hours by several minutes each day until the summer solstice in late June. On that day, the sun will reach its highest elevation in the sky directly over the Tropic of Cancer at approximately 27 degrees north latitude above the equator, bringing us our longest day and shortest night of the season.

Observing: 

The evening sky has become a lonely place for observing the planets. Jupiter is not visible at all, as it is in conjunction with the sun for the month. Most of the activity happens in the southeast just before dawn. There is a quartet of planets visible on the morning of March 2. Look to the southeast about 45 minutes before sunrise. Here, clustered around the constellation Capricorn is a close meeting of Mercury, Mars, Saturn and Venus. However, one must be on a flat expanse or a hilltop with an unobstructed vista below to view Mercury and Mars, since the two planets are just three degrees above the horizon. At the same time, and affording an easier view, are brilliant Venus above a dimmer orange Mars about 25 degrees above both Mars and Mercury.

On March 8, the half-moon can be found directly between the Hyades and Pleiades star clusters in the constellation Taurus. The Hyades is to the left of the moon and includes the red giant star Aldebran, the eye of Taurus the bull. The Pleiades is just to the right of the moon. This is a good night to step out around 8 p.m. and view these two star clusters. Using the moon as a guide is one of the best ways to learn one’s way around the celestial sphere. On the morning of March 15, both Mars and Venus are very close together, separated by only four degrees (one degree is approximately two moon diameters). The two planets have been narrowing the gap between them all month as Mars slowly rises each day and Venus gradually sinks lower in the sky. The best day to observe the planets is about 40 minutes before sunrise on March 28. On this date, Venus, Mars and Saturn are arrayed in a triangle in the constellation Capricorn with the crescent moon below the three planets, guiding us to exactly where in the eastern horizon to find this vista. 

Meteor showers:  

There are no significant meteor showers in March.

James Webb telescope:  

The telescope reached its final orbit at Lagrange point 2, approximately one million miles from Earth. Since establishing orbit it has begun deploying systems and initiating electrical and mechanical startups, aligning mirrors and deploying the sunshield which will protect its delicate systems from the heat of the earth, moon and sun. The scope is now in what is called the “commissioning phase,” expected to last five months, during which the mirrors are being finely adjusted and the optics calibrated. 

Moon phases:

March 25: Last quarter (left half of the moon illuminated). Moon is waning or decreasing in size.

March’s full moon was known by Native American tribes as the Worm Moon, which refers to the fact that earthworms and grubs tend to emerge from their winter dormancy at this time of the year, attracting robins and marking a sign of spring.