CANCELED Solar Star Party, Mar. 20, Bldg 1 main cafeteria patio


What: Solar Observing
Where: Building 1 Main Cafeteria Patio
When: Tuesday, March 20, noon to 1:00 pm

Come view the Sun, our very own star, with the APL Astronomy Club. Count sunspots, see faculae and plages and maybe granulation and spicules, and compare the view through different kinds of equipment. Venus and Jupiter will also be visible in regular telescopes.

Open to anyone on campus who is interested.

If it’s too cloudy the event will be canceled, but we’ll try again on April 17, at either the Bldg 17 cafeteria patio, or MP6 cafeteria patio.

10:30 am EDT:  Canceled. The sky is currently socked in, and forecasts agree that will not change.  So, in the hopes of guaranteeing a few hours of noon-time sunshine today, we have canceled this event.

Looking Up April 2012

Daylight hours continue to increase in April, as the Earth spins through spring towards summer. Early in the month (about April 4th) the sun will rise at 6:45 am EDT, and set by 7:36 pm.  Towards the end of the month (about April 20th) the sun will rise at 6:20 am, and set by 7:50 pm.   The moon will be at Full phase on April 4, 3rd quarter on April 13, New on April 21 (a happy circumstance for the Lyrid meteor shower), and 1st quarter on April 29.

On April 2-4 Venus glides past the Pleiades (the Seven Sisters and their parents).  The stars of the Pleiades cluster are only moderately bright (third and fourth magnitude), and brilliant Venus will outshine them by 8 magnitudes.  Closest approach will be April 2nd, when Venus passes less than half a degree the brightest sister Alcyone (for comparison, our Moon is about half a degree wide).  Venus remains the brightest object in the evening sky (barring the Moon), and will be visible for at least 3 hours after sunset every clear evening.   By the end of the month, Venus will appear as a fat crescent, as it moves around the Sun towards inferior conjunction (and transit!) on June 5th.

Mars is the second brightest planet in the evening sky, high over the south-eastern horizon at sunset.  Mars is still in the retrograde phase of it’s dance with Earth, and will spend the entire month hanging out in the constellation Leo near the bright first magnitude star Regulus. Mars is about 3 magnitudes brighter than Regulus, and will be obviously reddish to most people.   The Big Dipper can be used to find Leo and Regulus: first use the Big Dipper’s pointer stars to find Polaris (the North Star), then trace back the opposite direction, across the zenith of the sky (you’ll want to spin around to face South at this point, or you’ll fall over backwards 😉 to the first bright star you come to – that’ll be Regulus – and this year Mars will be right there, too.

Jupiter gradually disappears into the western sunset as the month progresses, while Saturn moves into the evening sky.  Saturn reaches opposition on April 15th, and will be zeroth magnitude.  The rings continue opening from their edge-on appearance in 2009, and this year will be tipped towards Earthly viewers by a full 15 degrees; the maximum  opening of 27 degrees will occur 13 years from now, in 2025.

The Lyrid meteor shower is predicted to peak on April 21, the same date as the New Moon, so there will be no moonlight to wash out the meteor trails.   City lights can definitely wash out meteor trails, so if you’d like a really good view plan to spend your pre-dawn hours as far from street lights and dark-phobic neighbors and car dealerships as you can get.   This shower is usually not too spectacular, with average Zenith rates of only 18 per hour, but the meteors are relatively swift, owing to the Lyrid orbit relative to Earth’s orbit, some can be spectacularly bright, and about 1 in 5 leave a train that persists for several seconds.

That’s all for this month.   And, as the great Jack Horkhemier used to say, Keep Looking Up!

Helen Hart, 19 March 2012; references:  the Astronomical Calendar, Starry Night planetarium program, USNO Astronomical Data Services.

Looking Up March 2012

Daylight Savings Time starts March 11.  Spring Equinox occurs March 20 at 05:14 UT (1:14 am EDT).  The Moon is Full on March 8, and New on March 22.

The evening sky is dominated by the constellations Orion and Canis Major (the Big Dog) towards the south, and by planets Venus and Jupiter, shining high and bright above the south western horizon at sunset; Venus is the brighter of the two.  Early in the month, Jupiter is higher above the horizon than Venus; on March 12, the two will be only 3 degrees apart, and will set at the same time, about 11 pm;  after the 12th, Jupiter and Venus appear to move apart, and Venus is higher in the sky than Jupiter.  On March 25-26 the young Moon passes near both planets, which should be a pretty sight.

Mars rises in the east around sunset and will be visible all night, shining almost as brightly as the star Sirius in the constellation Canis Major.  Mars reaches opposition on March 3; because Mars is near aphelion, its apparent size is relatively small, less than 14 arc-seconds at best.  Mars is in the middle of its northern hemisphere summer, so the North polar cap will be visible through a moderately sized telescope.

Saturn rises after 10 pm by the end of the month, and isn’t well placed for viewing until midnight.  Early in the month both Saturn and Mars are visible above the western horizon in the morning before sun rise.

Helen Hart, 17 Feb. 2012;  references:  Starry Night planetarium program, USNO Astronomical Data Services.