Category: Astronomy

Greetings, fellow SkyWatchers! Are you ready for what’s hot and what’s not this weekend? Then start by taking a look at Anders Celsius and then journey to some challenging lunar features! Evolve your selenographic knowledge by locating Darwin and double your vision with binary stars. Monkey around? You bet! But only if it’s with a star with unusual spectral qualities that you can see! Whenever you’re ready, I’ll see you in the dark…

Friday, November 27, 2009 – Today is the birthday of Anders Celsius, born in 1701. Although you might easily recognize the name Celsius in connection with temperature, you might not know about the contributions Anders made to astronomy some three centuries ago. Born to a Swedish family of mathematicians and astronomers, one of his first achievements came when he participated in an effort to determine the true shape of Earth. He was also the very first scientist to recognize the connection between magnetism and the aurora. And, by age 39, he had become the director of an observatory. Celsius also developed the first instrument for measuring the brightness of starlight. Ever resourceful, he already possessed tools to measure position and motion but had nothing with which to gauge magnitude. His idea was so simple it was downright elegant: he simply blocked the light with identical glass plates until the star disappeared. The brighter the star, the more plates it took!

Tonight let us go from one extreme to another as we begin on the northernmost limb of the lunar surface. From the northernmost Sinus Roris, look for lens-shaped crater Markov. To Markov’s northeast is a large, flat crater with very few distinguishing characteristics. Its name is Oenopides.

If conditions are stable, look for a gray slash known as Cleostratus on the lunar limb further north of Oenopides. On the southern limb, look for familiar craters Wargentin, Nasmyth, and Phocylides. Even farther south, note the long oval Pingre.

Saturday, November 28, 2009 – On this date in 1659, Christian Huygens was busy at the eyepiece, but he wasn’t studying Saturn. This was the first time any astronomer had seen dark markings on Mars! Why don’t you try your luck at Mars tonight, too? Wait for it to rise well above atmospheric disturbance and power up! It’s too bad it isn’t – or as big (!) as close as the Moon. . .

Tonight the great Grimaldi will again capture the eye, but let’s head southeast for another featureless dark gray oval, Crueger.

Continuing south, the next crater—Darwin—is hard to see because of its rather un-craterlike appearance. Darwin is best caught by focusing on the rima that includes its eastern wall. Look for a Y formation pointing toward Crueger.

Although skies are bright, we can still see double. Locate 5-magnitude Lambda Arietis (RA 01 57 55 Dec +23 35 45) and its companion. This wide pair is an excellent challenge for binoculars. Both stars are F-spectral types and should appear ivory in color to most observers. Having trouble in binoculars? Try a finderscope of equal power and aperture. To locate Lambda, look a finger-width west-southwest of Hamal, at Alpha Arietis.

Sunday, November 29, 2009 – On this date in 1961 Enos the Chimp was launched into fame! His story is a long and colorful one, but Enos was a true astronaut. Selected to make the first American orbital animal flight only 3 days before the launch, he flew into space on board a Mercury-Atlas 5 and completed his first orbit in just under 90 minutes. Although Enos was scheduled to complete three orbits, he was brought back due to ‘‘attitude difficulties.’’ But whose? Malfunctions caused the chimp to be repeatedly shocked when performing the correct maneuvers, but Enos continued to perform flawlessly and was said to run and jump enthusiastically on board the recovery ship. Although he died a year later from an unrelated disease, Enos the chimp remains one of our most enduring space heroes.

Tonight, launch your way toward the Moon and see if you can spot crater Riccioli. . . You’ll find it centermost and almost on the limb!

Now that you’ve viewed a challenging crater, would you like to have a look at a challenging double star? All you have to do is locate Theta Aurigae (RA 05 59 43 Dec +37 12 45) on the east side of the pentagonal shape of this constellation. Located about 110 light-years away, 2.7-magnitude Theta is a four star system, whose members range in magnitude from 2.7 to 10.7. Suited even to a small telescope, the brightest member—Theta B—is itself a binary at magnitude 7.2; it was first recorded by Otto Struve in 1871. The pair moves quite slowly and may take as long as 800 years to orbit at their separation of about 110 Astronomical Units (AU). The furthest member of this system was also noted by Struve as far back as 1852, but it is not a true member, with the separation only occurring thanks to Theta’s own proper motion. While you are there, be sure to note Theta’s unusual color. Although it will appear ‘‘white,’’ look closely at the diffraction caused by our own atmosphere, which acts much like a prism. You’ll notice a lot more purple and blue around this star than many others of the same spectral type. Why? Theta is a silicon star!

Until next week? Ask for the Moon, but keep on reaching for the stars!

This week’s awesome images are (in order of apppearance): Anders Celsius (widely used image), Northwest Limb Mosaic (credit—Alan Chu), Crueger (credit—Alan Chu), Lambda Arietis (credit –Palomar Observatory, courtesy of Caltech), Enos the Chimp (credit–NASA), Riccioli (credit—Alan Chu) and Theta Aurigae (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

Greetings, fellow SkyWatchers! Yep. The Moon is back, but this weekend can still present some great opportunities for enjoying astronomy. If you’re up early or out late? Well, hey… The Leonid meteor shower is still producing activity! Why not take a few minutes to learn about a great variable star you can follow without optical aid or study a new lunar feature? There’s plenty to do for binoculars and small telescopes – and perhaps even a clever new study you haven’t looked at yet! Whenever you’re ready, I’ll see you in the dark…

Friday, November 20, 2009 – Today celebrates the birth of a significant astronomer, Edwin Hubble. Born on this date in 1889, Hubble became the first American astronomer to identify Cepheid variables in M31, which in turn established the extragalactic nature of the spiral nebulae. Continuing with the work of Carl Wirtz, and using Vesto Slipher’s redshifts, Hubble could then calculate the velocity–distance relation for galaxies. This has become known as Hubble’s Law and demonstrates the expansion of our universe.

Tonight we’ll pass the Moon and head just a little more than a fist-width west of the westernmost bright star in Cassiopeia, to have a look at Delta Cephei (RA 22 29 10 Dec +58 24 54). This is the most famous of all variable stars and the granddaddy of all Cepheids. Discovered in 1784 by John Goodricke, its changes in magnitude are not due to a revolving companion but rather the pulsations of the star itself.

Ranging over almost a full magnitude in 5 days, 8 hours, and 48 minutes precisely, Delta’s changes can easily be followed by comparing it to nearby Zeta and Epsilon. Upon reaching its dimmest point, it will brighten rapidly in a period of about 36 hours yet take 4 days to slowly dim again. Take time out of your busy night to watch Delta change and change again. It’s only 1,000 light-years away and doesn’t even require a telescope! (But even binoculars will show its optical companion.)

Saturday, November 21, 2009 – Tonight let’s go to the southern lunar cusp to identify two small but very nice craters. Using previous study Fabricus, continue south and look for the pair connected side-to-side rather than end-to-end.

This is crater Watt, with Steinheil intruding on it. Remember the distance traveled south from Fabricus to this pair and extend that distance even further south. Seen on the limb is crater Biela. If conditions are stable, you might pick up a tiny black point in Beila’s west wall, Biela C.

Before we retire to the shadows tonight, let’s study the small, open cluster NGC 225, located a finger-width northwest of Gamma Cassiopeiae (RA 00 43 42 Dec +61 47 00). This 7th magnitude collection has been described by some as looking like a sailboat. A fascinating name might be the ‘‘Metamorphosis Cluster,’’ since the southwestern region of the cluster looks like a butterfly asterism and, to the northeast is the caterpillar-like asterism. Although just barely detectable as an unresolved patch through binoculars on a dark night, tonight’s Moon means that magnification is needed just to make out its half-dozen brighter 9th magnitude members. Modest scopes should reveal two dozen stars to magnitude 12.

Sunday, November 22, 2009 – On the lunar surface tonight, the three rings of Theophilus, Cyrillus, and Catharina will emerge, but tonight let’s power up on Theophilus and see what we can find! The area just northeast of Theophilus—where Mare Tranquillitatis and Mare Nectaris join—is called Sinus Asperitatis.

Toward its center, you will see the remains of a once grand (nameless) crater holding the younger, sharper Torricelli in its center. Dropping back to Theophilus, just outside of its east wall, you will also find a young crater, Madler. As you head east across the northern shore of Mare Nectaris, look carefully for two partial rings. The northernmost is so eroded that it never received a name, while a slight, faint horseshoe marks all that remains of Daguerre.

Tonight let’s test our starhopping and observing talents by starting first with a beautiful double – Gamma Arietis. Now look about a fist-width east-southeast for dim little Pi. When you have Pi centered, move about half a degree southwest for an alternative catalog study—DoDz 1.

Although you might find this sparkling double handful of stars of little interest, think twice before you hop on. Although DoDz studies are far more scattered and less populous than most galactic clusters, it doesn’t make them less interesting. What you are looking at are basically the fossils of once active and more concentrated regions of stars. As the cluster has matured, the lower mass members have been stripped away and joined the general population. Known as a ‘‘dissolving cluster,’’ DoDz 1 is all that’s left of a far grander collection. Very ancient. . .yet still very beautiful!

Enjoy your celestial adventures!

This week’s awesome images are (in order of appearance): Edwin Hubble (widely used public image), Delta Cephei (credit—Palomar Observatory, courtesy of Caltech), Steinheil and Watt at limb (credit—Alan Chu), NGC 225 (credit—Palomar Observatory, courtesy of Caltech), Theophilus, Cyrillus, and Catharina (credit—Alan Chu) and Dolidze-Dzimselejsvili 1 (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!