By Tammy Plotner
Friday, May 10 - Today we celebrate the birth of Cecilia Payne in 1900. Payne was the first to apply the laws of atomic physics to study the temperature and density of stars. It was a difficult time for female astronomers, and she had quite a time getting her peers to take her work seriously. Payne proved that hydrogen and helium are the two most common elements in the universe and, with the later help of Fred Hoyle, proved that our Sun is 99% hydrogen and helium.
This is the official date of New Moon and we 'll begin our celestial adventures by taking a look at the constellation of Leo and its brightest stars. Wait until the skies are dark and look for a grouping of stars overhead that resemble a question mark. Our first destination is 85 light-year-distant Regulus - the point in the question mark. As the 21st brightest star in the night sky, 1.35-magnitude Alpha Leonis is a helium star about five times larger and 160 times brighter than our own Sun. Speeding away from us at 3.7 kilometers per second, Regulus is a multiple star system whose 8th magnitude B companion is easily seen in small telescopes. Regulus B is also a double star, with a magnitude 12 dwarf companion of uncertain type. There ' s an additional 13th magnitude star in this grouping, but it's probably not associated with Regulus, since the "Little King" is moving toward it and will be very close to it in 800 years.
Now, hold your hand out at arm's length. About a fist-width northeast of Regulus is 2.61-magnitude Gamma Leonis. Algieba is a very fine double star, but difficult to see at low power, since the 90 light-year-distant pair is bright and close. Separated by about twice the diameter of our own solar system, the gap between Algieba and its companion is slowly widening! Another two finger-width's north is 3.44-magnitude Zeta. Aldhafera is about 130 light-years away and also has an optical companion-35 Leonis. Remember this binocular pair, because they'll lead you to galaxies later! Before we leave, look east for 3.34-magnitude Theta, part of the triangle-shaped area that mark the Lion's hips. Mark this one in your memory, because Chort and 3.94-magnitude Iota to the south serve as markers for a galaxy hop! Last is easternmost 2.14-magnitude Beta. Denebola is the "Lion's Tail" and has several faint optical companions.
Saturday, May 11 - As the skies darken, seek out an unobstructed western horizon and look for the brilliant appearance of Venus low to the west just after sunset. Above it and slightly to the south, you'll see another bright "star." That's no star - it's Jupiter! Now, test your powers of observation and look between them. Do you see the very slender crescent of the Moon? Great work!
Tonight let's make use of what we have learned and do a galaxy hop that's relatively easy for larger binoculars and small telescopes. You'll find a pair of galaxies almost perfectly mid-way between Theta and Iota Leonis, and their names are M65 (RA 11 18 55 Dec +13 05 32) and M66 (RA 11 20 15 Dec +12 59 21). They were discovered by Pierre Mechain in March 1780, but apparently Charles Messier didn't notice the bright pair when a comet passed between them in 1773. At around 35 million light-years away, you will find M66 to be slightly brighter than its 200,000 light-year-distant western neighbor, M65. Although both are Sb-class spirals, the two couldn't appear more different. M65 has a bright nucleus and a smooth spiral structure, with a dark dust lane at its eastern edge. M66 has a more stellar-like core region with thick, bright arms that show knots to larger scopes, as well as a wonderful extension from the southern edge.
If you are viewing with a larger scope, you may notice to the north of this famous pair yet another galaxy. NGC 3628 (RA 11 20 16 Dec +13 35 13) is a similar magnitude edge-on beauty with a great dissecting dark dust lane. This pencil-slim, low surface brightness galaxy is a bit of a challenge for smaller scopes, but larger ones will find its warped central disk well worth high-power study. You may also be able to spot the ''Leo Trio'' and members of Arp's Peculiar Galaxy Catalog!
If you're still up to a challenge, then why not seek out the fading Comet PANSTARRS? If you can see Polaris, chances are good you can spot the speedy comet, too. Right now it is circumpolar and located on the Cassiopeia side of the "North Star." You can find it at approximately RA 23 48 23.5 Dec +75 27 28, depending upon the time of your observation. At an estimated magnitude 8.2, Comet L4 PANSTARRS is still within easy reach of the average-sized telescope and should be observable with large binoculars from a dark sky location.
Sunday, May 12 - Happy Mother's Day! As we're sky-watching tonight, let's take just a moment and give thanks for our mothers and the roles they can play in our lives. Did you know Johannes Kepler's mother, Katharina, was the one who inspired him? To rather paraphrase his story, Johannes' father was a mercenary soldier and left him and his mother when he was a young child. His mother supported them both by working as a waitress at the family inn and put the very religious and mathematically talented young Johannes through seminary school on her own. It was his mother who took him to watch the great comet of 1577 and an eclipse of the Moon - inspiring his love of astronomy. After he graduated, he became an assistant to Tycho Brahe, supported Copernican theory and worked with Galileo. While Kepler was working on his "Harmony of the World" his 70 year old mother was charged with witchcraft because she collected herbs, made potions and understood astrology. Isn't that about the way it went for anyone back then who was interested in the stars? Anyhow, Kepler got a lawyer and managed to save her from the fate of the aunt who raised Katharina. She was also burned at the stake for being a witch!
As the sunset fades away and skies begin to darken, look to the west again. Last night the Moon was between Venus and Jupiter and tonight it has journeyed higher and become easier to see. This awesome line up of astronomical objects is called a conjunction.
Tonight you've got dark skies ahead and hopefully an itch to see something out of the ordinary with your telescope. If so, let's go south and locate a fine reflecting nebula - NGC 2467 - in northern Puppis (RA 07 52 19 Dec -26 26 30). Sometimes referred to as the "Skull and Crossbones Nebula," this billowing cloud of gas and dust is easily found less than a finger-width south-southeast of 3.5 magnitude Xi Puppis.
Even small telescopes will find this expansive, star-studded emission nebula, a real beauty! Large aperture telescopes should look for neighboring splotches of nebulosity illuminated by small groupings of stars, some of which are part of a newly forming open cluster. Keep in mind while observing NGC 2467 that we are seeing it from a great distance. At 17,000 light-years away, this region of star formation is some 10 times farther away than the Great Nebula in Orion. If it were the same distance away, NGC 2467 would dwarf M42!
Until next week? Clear skies and happy hunting!
Tammy Plotner is a professional astronomy author, President Emeritus of Warren Rupp Observatory and retired Astronomical League Executive Secretary. She's received a vast number of astronomy achievement and observing awards, including the Great Lakes Astronomy Achievement Award, RG Wright Service Award and the first woman astronomer to achieve Comet Hunter's Gold Status.