To date it has been a superb winter for viewing the queen of the planets, Venus.  February marks the pinnacle of its evening visibility as it stands like a sequined showgirl nearly halfway up in the western sky at sunset. Currently shining at its greatest brilliance for this apparition, this dazzling evening star appears as a distinct crescent shape in small telescopes, which is growing progressively larger in size as it approaches our Earth.

And be sure to get out your calendar and put a big circle around Friday, February 27, 2009, for that evening a lovely crescent Moon will appear to snuggle up close to Venus, particularly for skywatchers across the Western Hemisphere.  It will make for an eye-catching scene as the two brightest sky objects of the night dominate the early evening scene for about three hours after sundown; even those who do not normally look up will likely have their attention drawn to this dynamic duo during their normal commute home from work or school.  What will make this array especially attractive is the fact that it will look almost three-dimensional; the Moon will look almost like an eerily illuminated blue and yellow Christmas ball hovering next to the brilliant-white diamond that is Venus.

Sadly, this will be the last in the current series of evening get-togethers between the Moon and Venus, for during March Venus will slide rapidly down into the sunset glow and by month's end will disappear from our evening sky until the spring of 2010.

But again . . . Friday night, February 27 will be the night when the Americas will be greeted with one of the most beautiful Venus-crescent Moon conjunctions possible. The pairing will persist from before sunset on into the depths of darkness.  The time when Moon and planet will appear closest will be around 8:30 p.m. Eastern time (7:30 p.m. Central, 6:30 p.m. Mountain, and 5:30 p.m. Pacific).  Venus will appear to hover approximately 1.5-degrees above and to the right of the 10-percent illuminated Moon (the Moon itself appears one-half degree in diameter).  For cities situated in the Mountain time zone, the time of closest approach will come during evening twilight, while for those in the Pacific time zone it takes place around, or just prior to sunset.

From other places around the world, the pairing will appear a bit different primarily because the Moon appears to move much more rapidly against the background stars than Venus, and also because of the effect of parallax: different viewing angles from different points on our planet.

From Europe, for instance, Venus will appear to hover majestically about 4-degrees directly above the Moon at sunset.  South Americans will see the Moon with Venus to its right; the pair low in the west-northwest at dusk and appearing to set side-by-side.  From Australia, the Moon will be positioned far to the lower left of Venus on the evening of Feb. 27 and a somewhat similar distance to its upper right the following evening.

Finally, if you're watching with some friends, here's a trivia question you might want to pose to them: Of the two which do they believe is the brighter: Venus now at its peak brilliance or the three-day old Moon?  The almanacs say that the Moon is 8.5 times (2.3 magnitudes) brighter, but because its light is not concentrated into a point like Venus, they may have a difficult time believing this!

January 24, 2009 marks an auspicious anniversary in the history of New York astronomy.  It is the 84th anniversary of the last total solar eclipse that was visible from New York City.  On January 24, 1925, the southern portion of the Moon's umbral shadow passed across upper Manhattan, parts of Queens and all of the Bronx.  Only in these locations would totality be visible; places like lower Manhattan, Staten Island and Brooklyn would unfortunately be outside the zone of the total eclipse.

So on a bitter cold morning (the air temperature hovered near 0 degrees F), but under a brilliantly clear, blue sky, millions of New Yorkers who properly positioned themselves, were able to briefly witness one of nature's greatest spectacles.  What made me think about this today was not so much the anniversary date itself, but the fact that like today, in 1925, the great event occurred on a Saturday.

I can recall as a very young boy, my grandfather telling me stories of how he and throngs of others watched this eclipse from along the East River Drive in East Harlem.

In 1970, just before the solar eclipse that swept along the US East Coast on March 7th of that year, I remember attending a meeting of the O.G. (Observing Group); a division of the Amateur Astronomers Association of New York.  The meeting was held in one of the basement classrooms of the old Hayden Planetarium and the topic that afternoon was: Can you remember the 1925 Eclipse?  Many participants who were there that day provided spirited anecdotes, such as AAA old-timers like Patrick Rizzo and Gilbert Schmidling.  Back then, the 1925 eclipse was still fresh in their minds . . . for it had occurred only 45-years ago.

Some years later, when I was the morning-drive meteorologist on WPAT Radio, I asked on the anniversary day if any listeners remembered that 1925 eclipse and was delighted to get about about a half-dozen responses from folks who indeed recalled that special day.  One woman wrote that she lived in Gravesend, Brooklyn back then: I don't remember much about the eclipse, so much as I recall that Papa woke me and my two brothers up very early that morning, bundled us up, piled us into our car and took us on what was then (for us) was a great adventure: We were going to the Bronx.  Another sent me an eclipse viewer—a piece of exposed film mounted on a piece of cardboard—dated January 24, 1925, with instructions on how to properly use it.  I've held on to this for many years, wrote the listener, adding . . . maybe you can put it to some use.

It is a sobering thought as type these words that I realize that virtually all of those people who saw the 1925 eclipse have passed on to the great beyond.  Indeed, to have any good memory of that event of so long ago, a person would have had to attain the age of five, meaning they would be 89 today; those few who are still with us are not likely to be around when the next total solar eclipse sweeps across the Continental US in 2017.

Certainly most of us are not likely to be around when the umbra touches NYC again . . . on the first of May in 2079.

I would suppose that in that in 2017, there might be some kind of a pre-eclipse gathering of those who will vividly recall the US East Coast Eclipse of 1970.  After all, that event will have occurred only 47-years earlier.  I can already see myself talking to a group of fresh-faced young people, most of whom probably will have never been exposed to the panoply of phenomena that accompany that magic word Totality! listening intently to me—an old-timer, describing a memorable event from a era which to them might seem almost like the stone age: the '70s.

Getting back to 1925, I'll finish this off on a somewhat ironic and eerie note.

On the morning of January 24, 1925, millions of New Yorkers were eagerly awaiting that magic moment when the Moon's umbra would descend upon their great city and briefly plunge them all into darkness.  Newspapers had been publicizing the time for weeks, so that when the big day finally arrived virtually every man, woman and child knew when that eagerly awaited moment would come.

It was 9:11.

Here is a YouTube link to a short film, showing preparations being made at Lakehurst, NJ to observe the 1925 eclipse from the Airship, Los Angeles . . . which was then the largest in the world.  There are also views of the partial stages and totality which was observed near Montauk Point, Long Island at an altitude of 3,000 feet.

Wait a second. The start of next year will be delayed by circumstances beyond everyone's control. Time will stand still for one second on New Year's Eve, as we ring in the New Year on that Wednesday night. As a result, you'll have an extra second to celebrate because a Leap Second will be added to 2008 to let a lagging Earth catch up to super-accurate clocks.

By international agreement, the world's timekeepers, in order to keep their official atomic clocks in step with the world's irregular but gradually slowing rotation, have decreed that a Leap Second be inserted between 2008 and 2009.

The extra second, ordered by the world's nominal timekeeper, the International Earth Rotation and Reference Systems Service, will be marked officially at the stroke of midnight on Wednesday in Greenwich, England, the home of what is popularly known as Greenwich Mean Time (GMT)—Coordinated Universal Time (UTC) to the more technically inclined—the standard time for the planet.

So at precisely 23:59:60 at Greenwich, England, on New Year's Eve, there will be a one-second void before the onset of midnight and the start of the New Year. Wednesday will see the 24th Leap Second that has been needed since the practice was initiated in 1972, and will be the first in three years.

Keeping the Earth on time

Around the world, to satisfy the requirements of navigators, communication organizations and scientific groups, about 200 atomic clocks in over 50 national laboratories worldwide will be adjusted at local times corresponding to midnight to local times at Greenwich. On New Year's Eve, the master clock at the United States Naval Observatory will be adjusted at 6:59:60 p.m. EST, or 23:59:60 GMT.

The extra second is needed to keep the world's clocks in time with the rotation of the planet. Time measured by the rotation of the Earth is not uniform when compared to time kept by atomic clocks. Today's atomic clocks have an inaccuracy of less than one second in 200 million years.

But for various reasons—the sloshing molten core, the rolling of the oceans, the melting of polar ice and the effects of solar and lunar gravity—our planet rotates on its axis at irregular rates, and on average has been falling behind atomic time at a rate of about two milliseconds per day. It now trails the official clock by about six-tenths of a second.

As a result of this difference, atomic clocks can get out of sync with the Earth and periodically have to be adjusted. Since it's the atomic clocks that are used to set all other clocks, a Leap Second has to be added from time to time to make up the difference.

Adding the extra second between 23:59:59 on Dec. 31 and midnight on Jan. 1 will put Mother Earth about four-tenths of a second ahead of the clock, giving her a bit of a head start as 2009 begins.

Who said chivalry is dead?

How to see and hear the extra second

Today many retailers market radio clocks as atomic clocks;" though the radio signals they receive usually come from true atomic clocks, they are not atomic clocks themselves. Typical radio atomic clocks require placement in a location with a relatively unobstructed atmospheric path to the transmitter, perform synchronization once a day during the night-time, and need reasonably good atmospheric conditions to receive the time signals.

If you own such a device, you might want to watch what your clock displays just before 0 hours GMT, Jan. 1, which corresponds to 7 p.m. Eastern standard time on Dec. 31. The minute beginning at 6:59 p.m. EST will contain 61 seconds. When a Leap Second was added in 2005, I watched my own clock closely during that minute as the seconds ticked off. When the final second of that minute was reached, the number 59 flashed not once, but twice!

If you don't have a radio clock, you can bring up a time display on your computer by going to: http://nist.time.gov/.

You can also listen for the Leap Second by tuning in to a shortwave time signal station. In North America, the extra tick can be heard by listening either to station WWV out of Fort Collins, CO at 2.5, 5, 10, 15 and 20 megahertz, CHU in Ottawa, Canada 3330, 7335, and 14670 kilohertz, or see other shortwave time signal stations for other parts of the world. (Note that CHU 7335 will cease broadcast on this frequency immediately after the leap second and move to 7,850 kHz thereafter.)

Should you encounter poor reception, try preparing a seconds pendulum by hanging a small weight on a string about 39.1 inches (99.3 centimeters) in length. Adjust the string length beforehand until the swings exactly match the time signal ticks. If the beeps denoting the start of each minute occur at the left extreme of a swing before the final (GMT) minute of 2008, they will be heard at the right extremes thereafter. (Although the swing amplitude will be steadily dying down, this does not affect a free pendulum's oscillation period.)

Ball Drop too early?

By the time the transition from 2008 to 2009 arrives in North America the Leap Second will have already been inserted into the world's timescale. But there was a bit of confusion about all this back in 1972 when the first Leap Second to be inserted on a New Year's Eve took place. One of our astronomers here at the Hayden Planetarium took a phone call that day from one of the engineers who was assigned to drop the famous illuminated ball in Times Square (in those days, the ball was slowly lowered using an old fashioned rope and pulley. See: http://www.crviewer.com/Targets/061108/historyBall.jpg). This can affect our jobs, he reportedly said. So we want to be sure we don't drop that thing one second too soon!

Regardless of how you use your extra second, just keep this one indisputable fact in mind: Whenever you note the time on the clock, realize that it is now—right now—later than it has ever been.

Happy New Year!