In March, the earth warms up and spring flowers bloom; exciting astronomical phenomena are waiting for us. The protagonist of the sky this month is undoubtedly the beautiful Saturn, while Mars and Venus are also good objects for observation. Furthermore, March is the perfect season for the Messier Marathon. Many interesting and misty deep-sky objects will undoubtedly greatly pique our interest in the mysterious spring night sky. Here is an e-book: “Messier Marathon Year-Round Guidance Manual”, which beginners may use as an introductory reference.
The Messier Marathon is a relatively strong self-challenge activity. Although all Messier objects appear in a single night, because their rising times vary greatly, the angles of some objects are very low, making them not very suitable for observation. Moreover, observing 103 objects in one night requires considerable time even if you are very familiar with the starry sky and equipment performance (of course, if you have a motorized equatorial mount and autoguiding input, it becomes very simple). This will be a very strenuous activity that requires full preparation. Those who love challenging difficulties, go ahead and explore our universe!
Astronomical Overview
March The Sun moves from Aquarius to Pisces.
March 01, 00:38 Full Moon; the largest full moon of the year visible in China.
March 02, 18:00 Saturn in conjunction with the Moon.
March 04, 07:00 Uranus in conjunction with Venus.
March 11, 16:00 Mars stationary, turning to prograde motion.
March 14, 21:00 Mercury in superior conjunction with the Sun.
March 14 Peak of the \gamma-Normids meteor shower (ZHR \sim 6).
March 15 Venus in conjunction with the Moon.
March 21, 01:32 Vernal Equinox.
March 22, 00:37 Saturn at opposition, magnitude 0.4.
March 25, 22:00 Mars in conjunction with the Moon.
March 30, 02:00 Saturn in conjunction with the Moon.
March 30, 10:00 Full Moon; the second full moon of March 2010 (Blue Moon).
Comets and Asteroids
March 24 Comet C/2009 O2 (Catalina) passes perihelion (0.695 AU, magnitude approx. 9).
March 23 Asteroid 532 Herculina at opposition.
Moon Dynamics
March 01, 01:00 Full Moon
March 07, 24:00 Last Quarter
March 16, 05:00 New Moon
March 23, 19:00 First Quarter
March 30, 10:00 Full Moon
March 02: Saturn in Conjunction with the Moon
March 14: Peak of the \gamma-Normids Meteor Shower
In last month’s forecast, we introduced a southern sky meteor shower—the \alpha-Centaurids. In March, another meteor shower with a radiant in the southern celestial hemisphere, the \gamma-Normids, enters our field of vision. Compared to the former, the radiant of this meteor shower is not as far south, with a declination of about -50^\circ, so more regions in China will be able to observe it.
Norma is a constellation in the southern sky with a fairly large area but no particularly bright stars. Surrounded by constellations such as Scorpius, Sagittarius, Centaurus, and Lupus, Norma is located in the direction of the Galactic Center as seen by observers in our solar system. It belongs to the constellations of the southern summer night sky (June to August is the best time for observation). If you have taken wide-angle photos of the summer Milky Way, you can see a clear dark band in the direction of its center, which is formed by interstellar dust in the plane of the Milky Way blocking the starlight from the core. This dark band happens to cross Norma diagonally, so as long as you find this dark band in the Milky Way, you have found Norma. Due to its location in the southern celestial hemisphere, Norma was also one of the constellations defined and named during the Age of Discovery; its prototype is actually a sounding instrument used on navigational ships, known in Latin as Norma, often abbreviated as Nor.
Norma itself is quite young, and the \gamma-Normids meteor shower is an even newer force among meteor showers. Its Latin name is \gamma-Normids, abbreviated as GNO. During its active period, the radiant moves through Lupus into Norma, with a meteor velocity of 56 kilometers per second. Southern meteor showers generally lack observation data, and this shower has only been confirmed since 1988 with the accumulation of observation records. Until 2007, its Zenithal Hourly Rate (ZHR) during the peak period basically remained around 6. Through analysis of limited observation data, the International Meteor Organization found that during the 4 to 5 days of the peak period, the ZHR can stay around 3, but the flow is likely to decay rapidly after the peak.
The activity of the \gamma-Normids in 2010 began in late February and will last until around March 22. According to the International Meteor Organization’s forecast, the peak may occur around March 14 to 15, Beijing time, and this night is also the best time for us to observe it. Although the flow of the \gamma-Normids is not large, that night happens to be the 29th to 30th of the first lunar month, so there will be no moonlight interference all night. Moreover, this period coincides with the Messier Marathon observation period. If you are interested, you can use a telescope to find 109 out of the 110 Messier deep-sky objects in a single night. Of course, this needs to be done in a certain order and is a multiple test of skill, physical strength, and patience for the observer, hence it is called a “marathon.” Some friends might be more interested in photographing deep-sky objects; if the weather is clear, this night is perfect for such attempts. Of course, if you have the interest to look at the \gamma-Normids in your spare time, that would be even better. Since the radiant of the \gamma-Normids is relatively far south, only regions south of 30 degrees North latitude are likely to observe meteors from this shower, and the further south, the better the observation conditions. For enthusiasts in northern China, there is no need to include this meteor shower in the observation plan for this moonless night.
March 22: Saturn at Opposition
Among the eight classic planets in the solar system, Saturn is not the largest, not the closest to us, and does not appear the brightest, but its prominent feature is unforgettable: the beautiful rings. In 2009, Saturn received much attention precisely because its “proud” rings almost “disappeared.”
Saturn’s rings are located on the extension of its equator. Galileo first observed them with a telescope 400 years ago, but due to resolution limits, he thought they were appendages next to the body of Saturn. In 1659, the Dutch scholar Huygens identified them as rings detached from the body. In 1675, the Italian astronomer Cassini discovered a dark gap in the middle of the rings, later called the Cassini Division. Later, more refined observations confirmed that Saturn’s rings are actually composed of multiple ring systems. Although Saturn’s rings are wide, they are very thin, with an average thickness of only about 10 kilometers. Therefore, if they are exactly parallel to our line of sight, the rings will “disappear.” The inclination between Saturn’s equatorial plane and its orbital plane around the Sun is large. Seen from Earth, Saturn’s rings will show a north-south swing, which causes periodic changes in their shape. The time interval from the maximum angle of northern tilt to the next maximum angle of northern tilt is about 29.5 years, and its orbital period is roughly the same. During this period, Saturn’s rings will experience two periods of “disappearance.” From late 2008 to September 2009 was one such period, and after that, they began to tilt, allowing us to see the beautiful rings again.
Entering March 2010, Saturn’s rising time gradually advances, appearing in the eastern sky shortly after dark, and observation conditions are getting better. Saturn is at opposition on March 22, though the actual moment is 09:10 on the 23rd Beijing time. At this time, Saturn rises as the Sun sets, and we can observe it almost all night. At local midnight, Saturn is at its highest point in the sky, making it an ideal time for observation. During opposition, Saturn is in Virgo, with a magnitude of about 0.5, slightly brighter than Regulus in Leo to the west and Spica in Virgo to the east. It is not difficult to find in the spring sky. The next task is to photograph the rings.
To photograph planets like Saturn, the method differs slightly from deep-sky objects. We usually use a camera with adjustable exposure parameters connected to a long-focal-length catadioptric telescope. A camera like the ToUcam 840K can be used; its lens can be removed and replaced with an adapter for the telescope. While tracking accuracy is vital for long-exposure deep-sky photography, it is less critical for planetary imaging.
Because the camera can record 30 frames per second, we only need to capture a few hundred frames and stack them to get a detailed photo of Saturn. The total shooting time is less than half a minute, so as long as Saturn stays in the field of view, observation is possible even without tracking. In future articles, we will introduce specific methods for planetary photography.
Besides Saturn and its rings, Titan is also an important target. As Saturn’s largest moon, this satellite with a thick atmosphere is seen as a key to understanding the early Earth and the origin of life. Titan was the first Saturnian moon discovered, with a magnitude of about 8, and can also be captured using the methods mentioned above.
Solar System Information
Sun: Moves from Aquarius to Pisces. Awakening of Insects on the 6th at 00:46; Vernal Equinox on the 21st at 01:32.
Mercury: Superior conjunction on the 14th, moving from morning star to evening star. It is close to the Sun and difficult to observe.
Venus: Evening star, moving from Aquarius to Pisces. Low in the southwest at sunset, moving to the northwest late in the month. Altitude increases from 10 to 17 degrees, magnitude -3.9. Conjunction with Uranus on the 4th (0.7 degrees south), conjunction with the Moon on the 17th (7 degrees south).
Mars: In Cancer. Located in the southeast at sunset, sets around 04:00 the next day, magnitude -0.2. Turns from retrograde to prograde on the 11th. Conjunction with the Moon on the 25th (5 degrees north).
Jupiter: In Aquarius. Low in the southeast at sunrise, close to the Sun and difficult to observe.
Saturn: Retrograde in Virgo. Conjunction with the Moon on the 2nd (8 degrees north). Opposition on the 22nd, magnitude 0.5, rises in the southeast after sunset, visible all night. Conjunction with the Moon on the 30th (8 degrees north).
Asteroids: Vesta (4 Vesta) is in Leo, magnitude decreasing from 6.3 to 6.7. About 150 degrees from the Sun, suitable for observation.
Uranus: In Pisces. Conjunction with the Sun on the 17th. Difficult to observe.
Neptune: Moves from Capricornus to Aquarius. Magnitude 7.8.
(Main sources: “2010 Astronomical Grand View”, “Amateur Astronomer”, Stellarium, and other internet resources; compiled by Scientific Space)
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