Quadrantid Meteor Shower
The first major meteor shower of the year is active from December 28-January 12 and peaks on the night of January 3-4. It has a very narrow peak lasting only a few hours centered around 1:00 am, during which meteors seem to radiate from just off the tip of the Big Dipper's handle—a spot formerly occupied by the obsolete constellation Quadrans Muralis the Wall Quadrant. Averaging about 40 meteors per hour, this year's Quadrantids coincide with a waxing gibbous Moon that sets around the time of the peak and whose light shouldn't seriously interfere with observations, weather-permitting.
A rare event called a lunar occultation occurs on the morning of February 18. This happens because the orbits of the Moon and the planets are found roughly along the same plane and occasionally intersect, and it's possible for the Moon to come between Earth and a more distant planet—in this case, Mars.
As observed from San Francisco on February 18, Mars will already be behind the waning crescent Moon when the Moon rises at 3:38 am. However, since the Moon crosses the sky a little more slowly than the stars, skywatchers might be able to see the Moon move out of the way, allowing Mars to peek out behind its Moon's dark limb. Emergence will occur at 4:29:15 am PST, but the Moon will still be very low—only about seven degrees above the southeastern horizon. Observers should start looking about a minute or so before then, just in case, and from a site that has a low southeastern horizon to the Moon can be seen at all. Because Mars has a perceptible diameter, it'll fade in over several seconds as the Moon uncovers it, rather than winking on instantly as stars would.
Taking a leap
Every four years, February 29bet36体育在线真的吗 appears on our calendars, adding a 366th full day to the year, which is then called a leap year. This is necessary because Earth's orbit about the Sun—which defines a year—isn't exactly 365 days long, but a teeny bit longer, at 365.25 days.
If allowed to add up over time, this discrepancy would cause the calendar to lag behind certain Sun-based events such as equinoxes and solstices. In four years, for example, it would list the change in seasons one day behind when they actually occur. In 20 years, it would be five days out of sync, and every 120 years, it would be a month off. To correct for this, Leap Day is added every four years, which does well enough over a short period of time, but additional rules have been added to refine the correction. Leap Day is added to years that are divisible by four (like 1952, 1996, or 2020, making them leap years), but not to century years, or those that are divisible by 100 (such as 1900 or 2100, which are not leap years), with the exception of those that are divisible by 400 (like 2000 and 2400, which are leap years). That's not confusing, is it? It's all so that the calendar keeps up with Earth!
When noon isn't really noon
The observational definition of "noon" is when the Sun is at its highest point, crossing an imaginary line called the meridian, which runs straight overhead from north to south—and from which we get the terms "am," or "ante-meridiem," (before the meridian) and pm, or "post-meridiem," (after the meridian). However, when Daylight Time is observed (between the second Sunday in March and the first Sunday in November), we have moved our clocks forward one hour, so for 65 percent of the year, solar time (indicated by sundials) does not match clock time: wallclocks and wristwatches say 12:00 pm before the Sun reaches the meridian, and when it does, clocks read closer to 1:00 pm.
A pretty predawn posse of planets
About an hour before dawn on the morning of March 18, the Moon, Jupiter, Mars, Saturn cluster together low in the southeast, providing skywatchers with a spectacular view of four bright solar system objects, all which would be enclosed within a space smaller than your fist, held at arm's length. If you count elusive Mercurybet36体育在线真的吗—straggling behind, 31 degrees to the lower-left of Saturn—that would be five objects.
Together, these represent not only half the solar system (four out of the eight major planets), but also account for 164 of the known moons of the planets of our solar system. However, only a few of these moons are visible to casual stargazers. The thin crescent of Earth's Moon, of course, is easily seen with the unaided eye, and the Galilean Moons of Jupiter are visible in small telescopes or even tripod-mounted binoculars, and more-distant Saturn reveals at least its largest moon, Titan, to small telescopes. Keep in mind that this clustering isn't limited to March 18 only—because of the slow movement of the planets, each at different speeds, it takes a number of weeks or even months for them to move into position, with the Moon being the wild-card, moving the fastest from one morning to the next and only briefly lining up with the planets. Be sure to check our Planets bet36体育在线真的吗section to find out when the more interesting configurations are happening.
Equal...something...as a new season springs into action
The vernal equinox arrives on March 19bet36体育在线真的吗 at 8:50 pm PDT, very shortly after the Sun has set due west. Traditionally recognized as the start of the spring season in the northern hemisphere (and fall in the southern hemisphere), this is one of two times during the year that the Sun crosses the plane of Earth's equator and is theoretically above and below the horizon for equal periods of 12 hours (equinox = aequus + nox, or "equal night").
However, that's not what we observe, because of optical effects caused by our atmosphere—and to a lesser extent how the words "sunrise" and "sunset" are variously defined. On the day of the equinox, the Sun is seen above the horizon for about eight minutes longer than it is hidden below during the night. A few days before that—March 16bet36体育在线真的吗—is when the Sun is visible (and not) for an almost-even 12 hours.
bet36体育在线真的吗A good option for beginning stargazers is a decent pair of binoculars as opposed to a more expensive and fragile telescope. Some astronomical objects, such as the Andromeda Galaxy or certain star clusters, actually look better in binoculars than a telescope, which may provide more magnification but such a narrow field of view that only a small part of the object can be seen.
bet36体育在线真的吗A standard, inexpensive all-purpose pair is usually described as 7x35. This means it magnifies seven times, and the objectives (the big lenses opposite the eyepieces) are 35 millimeters in diameter. So now you know what it means if it says 8x50 or 12x80. However, the bigger the aperture, the more light the binoculars gather, allowing you to see fainter objects, but the heavier they'll also be, and beyond about 50mm, you may need to start looking for a tripod to put them on (and make sure the binoculars are tripod-mountable). However, while a pair of binoculars might be perfectly adequate for daytime sports-viewing, the optics might not necessarily be aligned well enough to align stars into sharp pinpoints. This is why testing a pair out under the night sky before buying is advisable.
Visit an aquarium, planetarium, rainforest, and natural history museum—all under one living roof.
Download the Morrison Planetarium's 2020 Pocket Almanac to stay up-to-date on eclipses, meteor showers, satellite spottings, and more.