What’s Up This Week – Mar 21 – 27, 2005

Image credit: Alwyn Botha
Monday, March 21 – For readers looking for an exceptional morning challenge with either binoculars or small scopes, try 8th magnitude comet C/2003 T4 LINEAR. On this date it will be in the same binocular field west of the M2 and continue southeast toward Beta Aquarii over the next four mornings.

Tonight the most outstanding feature on the lunar surface will be the “Bay of Rainbows” – Sinus Iridum. Take the time to power up on the area and enjoy its many wonderful features such as bright Promontoriums LaPlace to the northeast and Heraclides to the southwest. It is ringed by the Juras Mountains where you will spot crater Bianchini in the center with Sharp to its west. Look for the punctures Helicon and Le Verrier in the smooth sands of Mare Ibrium and the long, smooth “dune” of Dorsae Heim interrupted by C. Herschel.

Tuesday, March 22 – Tonight there will be two meteor showers – the Camelopardalids and the March Geminids. While the Camelopardalids have no definite peak, they have a screaming fall rate of about one per hour and are the slowest recorded meteors at 7 kps. The March Geminids were discovered in 1973 and confirmed in 1975. The fall rate is usually about 40 per hour and they are considered “slow”. With the bright skies tonight, it will be difficult to distinguish them, but trace back to the point of origin to identify which stream.

While bright Aristarchus and the graceful old Gassendi will try to steal tonight’s lunar show, continue on towards the Southern Highlands to look for the long ellipse of crater Schiller near the limb. Small crater Bayer borders its northeastern edge.

Born on this day in 1799 was Friedrich Argelander, creator of the first international astronomical organization. Argelander also compiled star catalogues and studied variable stars. With deep sky studies improbable for the next few days, why don’t we try taking a look at a variable ourselves? RT (star 48) Aurigae is a bright cephid that is located roughly halfway between Epsilon Geminorum and Theta Aurigae. This perfect example of a pulsating star follows a precise timetable of 3.728 days and fluxes by close to one magnitude.

Wednesday, March 23 – Tonight let’s travel to the far southern edge of the lunar surface to visit three craters. Past study, the lava-filled Wargentin, is bordered by shallow Nasmyth to the east and Phoclydes to the southeast. This pair makes a wonderful “impression” on the Moon, for together they look like a giant shoe print!

The first photo of the Moon was taken tonight in 1840 by J.W. Draper. (Yes, it was done in 1839 by L.J.M. Daguerre – but contained no detail.) Why don’t you try as well? Camcorders, webcams and digital cameras are inexpensive ways of experimenting and even a common disposable camera can yield surprising results when held to the eyepiece of a telescope. Circle your thumb and index finger around the pair to aid in alignment and block stray light. Just click and say “green cheese”…

Thursday, March 24 – With the lunar terminator highlighting crater Grimaldi on the western limb, let’s try our hand at a more difficult feature. To Grimaldi’s east you will see the complex structure of crater Damoiseau. Extending from a break on its western rim edge is a long surface “crack” that runs north to south between the pair. This challenging feature is known as Rima Grimaldi.

On this night in 1893, Walter Baade – the developer of the concept of stellar population – became the first human to resolve the Andromeda Galaxy’s companions into individual stars. Tonight we’ll stay within our own galaxy as we travel 85 light years away to learn about “The Little King” – Regulus.

Ranking as the twenty-first brightest star in the night sky, Alpha Leonis is a helium type star about 5 times larger and 160 times brighter than our own Sun. Speeding away from us at 3.7 kilometers per second, Regulus is also a multiple system whose 8th magnitude companion is easily seen in small telescopes. The companion is itself a double at around magnitude 13 and is a dwarf of an uncertain type. There is also a 13th magnitude fourth star in this grouping, but it is believed that it is not associated with Regulus since the “Little King” is moving toward it and will be about 14″ away in 785 years.

Friday, March 25 – Tonight is Full Moon and time to explore the bright ray systems that criss-cross its surface. One of the strongest will eminate from crater Tycho and head toward the southwest limb. If libration is favourable in your area, you might catch a glimpse of the Doerful Mountains on the Moon’s edge. This incredible mountain range comes within a kilometer of being as tall as the Himalayas. If the Earth and the Moon were the same size, we would find the Doerfuls are three times higher than Everest!

On this date in 1655, Christian Huygens was still celebrating his earlier discovery of Saturn’s rings when he made an even more important contribution – Titan. 350 years later, the probe named for Huygens is now exploring Saturn’s largest satellite and you can as well. Even small telescopes can easily see the first moon discovered in our solar system to have an atmosphere. Before you observe, try checking the current positions of Saturn’s moons so you know precisely where to look.

Saturday, March 26 – Heads up southwestern Australia! The Moon will occult Jupiter for you on this this universal date. Please check this IOTA page to see a path map and compute times for your location. For the majority of northern hemisphere viewers, you will get to see a very pleasing conjunction of the two around 1 degree apart.

With the strong influence of the Moon to the east, let’s journey this evening towards another lovely multiple system as we explore Beta Monocerotis. Located about a fist width northwest of Sirius, Beta is one of the finest true triple systems for the small telescope. At low power, the 450 light year distant white primary will show the blue B and C stars to the southeast. If skies are stable, up the magnification to split the E/W oriented pair. All three stars are within a magnitude of each other and make Beta one of the finest sights for late winter skies.

Sunday, March 27 – Tonight as the Moon rises, check the eastern limb where you will see the terminator has advanced toward the eastern edge of Mare Crisium. With the shadows throwing its mountained walls into relief, we can see where this Washington state-sized area could possibly have been impact formed. Crisium is unique simply because it does not connect to any other mare. While the walls don’t seem that high at around 450 meters, that’s comparable to taking on the Vasques Cirque vertical drop at Winter Park, Colorado… without the skis!

Until next week? Keep smiling and looking up! May all your journeys be at light speed… ~Tammy Plotner