SKY REPORTER: April Skies

The International Space Station viewed from Space Shuttle Atlantis, May 23, 2010.
Credit: NASA

Along with warming breezes and shorter midday shadows, for me a sure sign of spring is Brooklyn Tech’s annual homecoming weekend. On my first day there as a student the English teacher had led off by asking if any of us had ever looked through an astronomical telescope! I was in heaven. Junior year we established an astronomy club, and welcomed as our first guest speaker Sune Engelbrektson from the Hayden Planetarium. I was very pleased later to become a colleague of this fine gentleman. Reminiscing with another Technite, Irving Shapiro then Director of the Harvard-Smithsonian Center for Astrophysics, we recalled racing from sixth floor classes up a flight of stairs to be first on line in the cafeteria. I once timed myself at 20 seconds flat for that sprint!

Two big events marked freshman year. In September Brooklyn lamented when the Dodgers played their final game at Ebbets Field. Ten days later the Space Age dawned when the Soviets launched Sputnik I, forever changing the world. During evenings of subsequent weeks we were on the roof of Flagg Court Apartments in Bay Ridge to watch that marvel cross the city sky. Status as a Tech student had sufficient cachet so everyone believed me when I pointed out a passing point of light as the object of our interest. One neighbor trying to be helpful was surprised when I told him his 1000 Watt photo floodlights would not improve our views of Sputnik. 

It was noted that if the Soviets could place a satellite a few hundred miles over America, they might do the same with weapons – and the Space Race became a national obsession. After we landed on the Moon competitive pressures deflated and cooperative international ventures gradually ensued. Americans now live in harmony near Russian counterparts aboard the International Space Station. Our folks travel there and back aboard a Russian craft, launched by Russian rockets from the Russians’ rented spaceport.

Let’s enjoy some April evenings while looking for current satellites. If you’ve never seen a spacecraft in flight, you needn’t travel much further than your front door. The International Space Station periodically passes over New York. The Heavens Above website provides information about when and where to look for that huge orbiter, as well as the prolific Hubble Space Telescope, and several lesser satellites. In addition to predictions of visibility provided up to ten days in advance, the site features real time interactive visualizations of the ISS passing over surface features. Before clicking for details about upcoming encounters, set the website for your locale. 

If on Tuesday evening April 7 under a clear New York City sky, you had looked above the western horizon between 7:57 and 7:58 p.m. along an imaginary line extending between brilliant Venus and the bright star Capella, you would have seen the International Space Station as it passed over central Pennsylvania heading northeast. At 7:58 the ISS would appear with a visual magnitude of -2.8 (as bright as Jupiter – at that time high in the southern sky). When planning for future passes, the most easily seen ISS flyovers occur when the spacecraft is at least 60 degrees of arc above the horizon at its highest elevations and shines with reflected sunlight at magnitude 0.0 or brighter. Optimal near zenith passes occur several times during most months.

A more challenging apparition is the small North Korean satellite KMS 3-2 which doesn’t quite reach naked eye visibility even during its most favorable overflights. A pair of 7x50 binoculars should show that little moon as it regularly moves up over the eastern seaboard at an altitude of about 300 miles. The 220 pound satellite was launched in December 2012 from Sohae Station, 75 miles northwest of Pyongyang.

For example, Thursday evening April 9^th, between 8:17 and 8:18 p.m. the KMS 3-2 satellite will cross over the Jersey shore on a northwesterly heading toward upstate New York and beyond. Its maximum elevation that evening is predicted for 8:17:00 p.m. when it may be seen high in the southern sky about one-third the way between Jupiter and the bright star Procyon in Canis Minor. As with the International Space Station and Hubble Telescope you can check Heavens Above to see 10 day updates for potential visibility dates later this month.  

The Moon

Planets

This month Venus and Jupiter continue as major features of our evening skies. Mercury moves into western evening twilight after that speedy planet’s superior conjunction with the Sun on April 10. Saturn arrives late these springtime evenings, rising at 11:30 at the start of the month, and a half hour earlier with each passing week. With some effort, Mars might be glimpsed low in the west for about an hour after twilight fades.

The brightest nova since 2013 has been fluctuating around magnitudes five and six during recent weeks. It’s located just under the “lid” of Sagittarius’ Teapot shaped asterism.

At the start of April the nova was brightening again toward magnitude four, a peak previously reached March 22. That brightness is similar to that of the middle stars in the Little Dipper. The nova is visible to unaided eyes under very dark skies and, with the help of binoculars or telescopes, from darkness-challenged urban areas. The nova rose at 2 a.m. on April first and arrives over our southeastern horizon four minutes earlier each subsequent day.

Wednesday April 8 the Moon may be seen close to Saturn at a separation of just one and a half degree of arc.

The evening of April 19 may give us the opportunity to catch a view of an exquisitely thin 29 hour “old” crescent Moon in the vicinity of Mars and Mercury. A half hour after sunset, at 8:10 p.m., the Moon is seven degrees above the western horizon and four degrees to the left of Mars. At that time Mercury is down at a slant to the right, about half Mars’ distance above the horizon.

Wednesday April 22 the Lyrid Meteor Shower peaks. This is one of the more vivid showers of the year. About 10 meteors per hour are usually expected, but in some years more than one per minute have been seen.

The evening of Thursday April 23, Mars is in conjunction with Mercury at an angular separation of about two degrees low in the western sky.

Astronomy Day is on Saturday April 25 this year. Member societies of The Astronomical League, a national umbrella organization, sponsor many events that day including opportunities to view the sky with telescopes provided by members from local clubs. The League had its origin here at the Hayden Planetarium when staff member Charles Federer and his wife Helen, founders of Sky & Telescope magazine, nurtured a plan by the Amateur Astronomers Association for an exhibition and convention of kindred spirits at the Hayden in conjunction with the 1939 New York World’s Fair.