Star Points for February, 2001; by Curtis Roelle Bright Planets Make Easy Targets This month provides a good opportunity to drag out that new Christmas telescope and see the three brightest planets, Venus, Jupiter, and Saturn. Each offers unique features visible in even the smallest telescope. The planet going through the most dramatic and noticeable changes right now is also the brightest planet in the night sky. Venus is gaining on Earth and is moving in between us and the Sun. As Venus draws nearer its apparent size will swell. Between New Year's Day and the end of February the apparent size of Venus will more than double. Something else to keep your eye on is the changing shape of Venus. In a telescope Venus goes through phases just like the Moon. In early February just a little less than half of the disc of Venus is illuminated. If you follow Venus with your telescope you may notice it shrinking to a thin crescent shape in the coming weeks. As Venus grows in apparent size and shrinks in phase, it also sets a little earlier after sunset each evening. The ironic thing about Venus however, is that it is so brilliantly bright that it is best viewed during bright twilight before the sky has completely darkened. Once in a dark sky its dazzling brilliance renders Venus difficult to observe comfortably. Higher up in the sky as twilight ends rules Jupiter, king of the gods and giant of the planets. Although currently about ten times farther away than Venus, Jupiter's intrinsically large size still causes its disc to appear larger in a telescope than Venus does. With a small telescope you may see some of the dark brownish or rusty colored bands that wrap around Jupiter. The two most prominent such bands lie on either side of the planet's equator. Thus they are referred to as the north and south equatorial belts. If you have a moderately large telescope you might also notice several of the other belts or the lighter colored bands. These creamy colored bands are called zones. From time to time Jupiter's "Great Red Spot" is visible in its southern hemisphere. Up until the 1980s the spot was noticeably red and dark. Then it faded to a pale pink and almost vanished from view. The red spot appears to be making somewhat of a comeback and seems to have darkened somewhat more. Jupiter rotates rapidly completing one rotation in a little under 10 hours. You can take advantage of Jupiter's rapid spin to see a lot of Jovian real estate in a relatively short time. In about five hours a telescopic observer can see the entire planet, front and back. With a small telescope, or even binoculars, you can follow Jupiter's four brightest moons. Their names are Io, Callisto, Europa, and Ganymede. Magazines such as "Sky & Telescope" and "Astronomy" include monthly charts that can be used to identify which moon is which on any given night. If you're lucky you might happen to catch a shadow of one of the moons as it transits across the face of the planet. A shadow will appear as a slowly moving tiny black dot. You can also find transit predictions listed for the entire month in tabular form in those magazines. Finally, very close to Jupiter in the sky, the planet Saturn shines down on February evenings. Saturn's most striking feature of course is its beautiful ring system. It is a wonderful sight in any sized telescope. If you look carefully you can see the shadow of Saturn cast by the Sun on the rings on the far side of the planet. Several of Saturn's brightest moons are visible in amateur telescopes. The brightest, Titan, is visible in just about any instrument. The larger the telescope the more moons will be visible. Sky & Telescope plots monthly positions for the five brightest moons, Titan, Rhea, Dione, Tethys, and Enceladus. What else is there to see in the sky besides planets? Between and a little above Jupiter and Saturn is the star cluster known as the Pleiades or Seven Sisters. Located in the constellation Taurus the Bull, the Pleiades are close enough to be visible to the unaided eye. To some people the Pleiades appear to form a small dipper, and it is often confused with the "Little Dipper" asterism of stars near the north celestial pole in the constellation Ursa Major. The Pleiades are viewed best in a telescope at low power or through binoculars. This is because a low magnification is needed in order to fit the entire cluster in the field. The Pleiades are also item 44 in the Messier catalog of "deep sky" objects. If you are looking for more challenging targets to point your telescope at the Messier catalog is an excellent place to begin. The entire catalog has about 110 entries. All of them are visible in small to intermediated sized telescopes. Next month we'll discuss more about the celestial gems in the Messier catalog. We'll also mention a viewing opportunity coming up in March where you can meet some local amateur astronomers for a night of observing Messier's objects with a variety of telescopes.