Wolverhampton Astronomical Society

Established 1951

This Months Planets & Deep Sky Tour March 2010

Planets for March 2010 for previous months click here to select a month.

The Planets

Bright and orange in colour, Mars really grabs your attention at the start of March but shows signs of fading towards the end. Dimmer Saturn is well placed and reaches opposition on the 22nd. Despite a rather thin showing of the famous rings, this beautiful planet may still have a surprise in store. Meanwhile, the inner planets, Mercury and Venus, are heading towards a conjunction at the end of March. Sadly, Jupiter, Uranus and Neptune are absent from this months sky, being to close to the Sun for safe observation.

MERCURY

BEST TIME TO SEE: 31st March, 20:00 BST

ALTITUDE: 9°

LOCATION: Pisces

DIRECTION: West

During the spring months, when the Moon planets appear close to the Sun, they are best seen in the evening sky and are rather poorly positioned if they're in the morning sky. Mercury in March emphasises this fact: it starts out in the morning sky being very difficult to see, and flips to the evening sky by the end of the month, becoming fairly easy to spot. The transition from a morning to an evening object takes place on the 14th, when Mercury is in superior conjunction with the Sun. After this date it takes a while for Mercury to emerge from the Sun's glow but it should be visible again from the 23rd onwards. The planet's visibility then continues to improve throughout the month. Try looking for the planet on the 31st, when it will appear 3.5° from mag. -3.8 Venus in the evening twilight. Throughout a scope, mag. -0.9 Mercury appears as a tiny gibbous disc (71% lit) 6 arcseconds across.

VENUS

BEST TIME TO SEE: 31st March, 20:00 BST

ALTITUDE: 9°

LOCATION: Pisces

DIRECTION: West

Venus is currently on the far side of it orbit from Earth and telescopically, this means that it's rather small at just 10 arcseconds across, and almost fully illuminated. The planet is brilliant at the moment at mag. -3.8 and is currently moving further from the Sun with each passing day. However, the expanding evening twilight prevents Venus from dazzling us in dark skies. Even so, you should be able to catch its intense dot quite easily in the west just after sunset. Try at around 18:15 UT at the start of the month at around 20:00 BST by the end.

MARS

BEST TIME TO SEE: 1st March 21:45

ALTITUDE: 61°

LOCATION: Cancer

DIRECTION: South

Mars is shrinking! Well, that's how it appears when you look at it through a telescope. This is because it's getting further away from us. So try grabbing a look at Mars at the start of the month, while it's still a reasonable 12 arcseconds across and quite bright at mag. -0.9. Catch the planet when it is due south and highest in the sky for the best view. Mars's size drops to 9 arcseconds across and at its brightest to mag. +0.2 by the end of March.

JUPITER

BEST TIME TO SEE: Barely visible this month

ALTITUDE: n/a

LOCATION: Aquarius

DIRECTION: East

After reaching solar conjunction on 28th February, Jupiter remains very close to the Sun and is nigh-on impossible to see in March.

SATURN

BEST TIME TO SEE: 22nd March, 00:15

ALTITUDE: 40°

LOCATION: Virgo

DIRECTION: South

Saturn reaches opposition on the 22nd, in the constellation of Virgo the Virgin. At this time it's opposite the Sun in the sky and this means it appears at its brightest to us and at its larges for the current period of observation. At the start of March, Saturn appears as a mag. +0.3 yellowish dot quite close to the mag. +3.9 star, Eta Virginis or Zaniah. On the 22nd, it will have brightened to mag. +0.2. Telescopically, Saturn isn't being presented at its best at the moment, with its rings still quite edge on to us. However, there is something to look out for around opposition, called the Seeliger Effect. This describes how a structure composed of many smaller components, such as Saturn's rings, appears to brighten when the light source that illuminates it (the Sun) is directly behind you. This is because when you and the light source are more or less in line, any shadows cast by the ring components appear in line with them and are difficult to see. When the light source is off to one side, the shadows can be seen and so the rings appear darker.

URANUS

BEST TIME TO SEE: Not visible this month Uranus is in conjunction with the Sun on 17th March and not visible this month.

ALTITUDE: n/a

LOCATION: n/a

DIRECTION: n/a

NEPTUNE

BEST TIME TO SEE: n/a

ALTITUDE: n/a

LOCATION: n/a

DIRECTION: n/a

Neptune is too close to the Sun to be seen this month.

DEEP SKY TOUR

Leo and Cancer offer up a host of deep sky delights this month

NGC 932

The stars Castor and Pollux are prominent in the early evening sky at this time of year, and direct you towards our first target. To the southwest of Pollux lies the mag. +3.5 star Delta Geminorum, or Wasat, and just over 2° to the east of this star you'll find a tenth magnitude planetary nebula known as \NGC 2392, the Eskimo or Clown Face Nebula. A 100x magnification with a 200mm scope shows the nebula as a multi-ringed bluish disk. A bright inner region surrounds the nebula's mag. +10.5 central star, and this appears separated from an outer halo by a dark ring. The outer halo is supposed to represent the fur lined hood of an Eskimo, the inner position being his face.

ALGIEBA

While Castor and Pollux represents the trailing edge of the winter night sky, the backward question mark of stars marking Leo's head represents the onset of the spring sky. The bright star at the base of the distinctive pattern, known as the Sickle, is Regulus - binoculars will easily show its eighth magnitude companion nearly 3 arcminutes away. Another, more impressive, double is the second star up in Sickle called Algieba. This much tighter pair requires a telescope and a reasonably high power to split it. The two components are of magnitude +2.0 and +3.6, and are separated by a rather small 4 arcseconds.

NGC 2903

Since the head of Leo the Lion (represented by the Sickle) it's worth mentioning the lovely spiral galaxy known as NGC 2903, which the Lion appears to have caught in its mouth. This is quite a bright galaxy, listed at mag. +8.9 and large enough at 12.6 x 6.6 arcminutes to contain yet another deep-sky object known as NGC 2905 - a bright star cloud embedded within the galaxy itself. A 200mm scope will show a wealth of detail here if you take your time. The elongated core is bright and, with high powers of 200-300x, it's possible to trace the start of the spiral arms as the feed of the core. A lovely object and highly recommended.

M44

If you look at the point roughly midway between Pollux and Regulus on a dark night, you should be able to glimpse the misty patch formed by the beautiful Beehive Cluster M44, if your skies are reasonably free of light pollution. Also known as Praesepe, M44 is estimated to be around 730 million years old. The object is perfect for viewing with a pair of binoculars or a telescope using a low power. There are an estimated 350 stars associated with M44 scattered in and around the general area. Look in particular for the house-shaped pattern that appears on its side.

M67

There's another interesting open cluster in Cancer, located 2° to the west of Alpha Cancri, also known as Acubens. Being much fainter than M44, the sixth magnitude M67 is often overlooked in favour of the Beehive Cluster. One of the reasons why M67 looks less impressive than M44, is that at 2,400 light years distant, it's about five times further away. It's also pretty old and, with an estimated age of around 4 billion years (that's around the same age as the Solar System) it ranks as the oldest of the Messier clusters. M67 is well suited to a power of around 100x and shows a number of older red and orange coloured stars.

M48

To the south of the faint inverted Y shape of Cancer the Crab is the distinctive sideways teardrop that forms the head of Hydra, the Water Snake. Located just inside the border of the Hydra, close to Monoceros the Unicorn, lurks another often overlooked cluster called M48. At mag. +5.5 this should be naked eye given dark skies, but it may be a bit too low from the UK. The cluster is quite large and suits low-power viewing. Careful scrutiny will reveal some nice patterns and swirls of stars; a 200mm scope reveals around 50 to 80 or so stars that populate this cluster