M19 is a magnitude +7.2 globular cluster visible with binoculars that's located in the constellation of Ophiuchus. It's an intrinsically large object that's highly oblate in appearance, loosely packed and partly resolvable using medium sized amateur telescopes. The cluster was discovered on June 5, 1764 by Charles Messier and first resolved into stars by William Herschel in 1784.
Finding M19 is easy as its positioned 8 degrees east of Antares (α Sco; mag. +1.0) the brightest star in neighbouring Scorpius. Located 4.5 degrees south of M19 is the slightly brighter Messier globular, M62 (mag. +6.8).
M19 is best seen from tropical and southern hemisphere latitudes during May, June and July. However, from northern temperate based observers it never rises particularly high above the southern horizon.
M18 is a small open star cluster located amongst the rich Milky Way star fields of Sagittarius. With an apparent magnitude of +7.5 it's easily visible with popular 7x50 or 10x50 binoculars, appearing as a somewhat dim hazy patch of light. The cluster was one of Charles Messier's original discoveries, which he catalogued on June 3, 1764.
M18 can be found not far from the "teapot" asterism of Sagittarius. It's positioned 8.5 degrees north and a little west of Kaus Borealis (λ Sgr - mag. +2.8), the teapot's top star. The surrounding area of sky is wonderfully rich for astronomers filled to the brim with numerous open clusters, globular cluster and nebulae. Two prominent examples are the Omega Nebula (M17) and the sprawling Sagittarius Star Cloud (M24), which are positioned one degree north and two degrees south of M18 respectively. All three objects are visible in the same binocular field of view.
The 2014 annual Lyrids meteor shower peaks on April 22nd and promises to be a better event than last year when the 85% illuminated Moon significantly interfered. For this year's spectacle the Moon is at last quarter (50% illuminated) rises a few hours before sunrise and hence not a massive factor. It's best seen from mid-latitude Northern Hemisphere locations.
The Lyrids shower activity last from April 16th to April 26th. Although the peak period is short it's also well worth looking in particular on the day before and after. Usually the meteors are of magnitude +2, but there are occasional fireballs that streak through the sky casting shadows for a short time and leaving a trail of dust and debris as they disintegrate in the Earth's atmosphere.
The Lyrids radiant is located inside Hercules very near to the border with Lyra and only 6 degrees from the 5th brightest star in the sky, Vega (magnitude 0.0). Normally the Lyrids are a reasonably strong shower and this year up to 20 meteors per hour can be expected. Contrast that with the year's best showers, the August Perseids and the December Geminids, both of which produce typical rates of 60 per hour.
Dwarf planet Ceres and Vesta the brightest asteroid both reach opposition in April and are currently positioned close together in Virgo, just northeast of Spica (α Vir) and Mars. Both objects are visible in binoculars as they travel quickly against the "fixed" background stars; their movements can even be tracked on a night-by-night basis.
On January 1, 1801, Italian Catholic priest and astronomer Giuseppe Piazzi discovered Ceres, originally believing it to be a comet. This new object between the orbits of Mars and Jupiter was initially classified as a planet and subsequently given its own planetary symbol. However with further discoveries all in the same region of the Solar System, the general term asteroids were coined to describe them. Much later in 2006, the International Astronomical Union (IAU) defined a new classification of dwarf planet of which Ceres is now a member. It has a diameter of 975 kilometres (610 miles) and can peak at apparent magnitude +6.7, beyond naked eye visibility but easy with binoculars.
Vesta was the fourth asteroid to be discovered on March 29, 1807 by German astronomer Heinrich Wilhelm Olbers. Despite being only the third largest body in the main asteroid belt - diameter 530 kilometres (330 miles) - Vesta is the brightest asteroid. It appears brighter than Ceres and the slightly larger Pallas since its approaches closer to Earth and has a much higher reflective surface. At favourable oppositions, the maximum apparent magnitude of Vesta is +5.1, putting it within naked eye visibility.
This year Vesta reaches opposition on April 13th (mag. +5.8) with Ceres reaching opposition on April 15th (mag. +6.9). The pair have not been this close together in the night sky - during an opposition period - for hundreds of years. During April they are positioned about 16 degrees northeast of Spica (α Vir - mag. +1.0). The much brighter red-orange Mars (mag. -1.5) starts the month just north of Spica but then quickly moves out westwards due its retrograde motion. Like Mars, Ceres and Vesta are also currently moving retrograde but since they are more distant they don't travel as fast against the constellation backdrop.
During April, Ceres is positioned 2.5 degrees northeast of Vesta with the latter being about 3 times brighter. Theoretically Vesta can be seen with the unaided eye, but this requires very dark skies. The two objects are so close together that they can be seen in the same binocular field of view.
At opposition, Vesta and Ceres are 1.232 AU (approx. 184.3 million kilometres or 114.5 million miles) and 1.644 AU (approx. 245.9 million kilometres or 152.8 million miles) distant from Earth respectively. Later on July 5th, Ceres and Vesta will be separated by just 10 arc minutes but by then they will have faded to magnitudes +7.4 and +6.2 respectively.
M14 is an eighth magnitude globular cluster located in the constellation Ophiuchus. It was discovery by Charles Messier on June 1, 1764, who described it as a "round nebula without stars". A few years later (1783), William Herschel became the first person to resolve M14 into stars. At 30,300 light-years from Earth this is one of the more distant globulars. However, since it's intrinsically bright M14 can be seen with binoculars, although at best appearing only as a out of focus faint "fuzzy star".
M14 is positioned in a rather barren area of sky and therefore locating it is not that easy. The cluster is positioned 8 degrees south and a little west of giant orange star Cebalrai (β Oph - mag. +2.8) the fifth brightest star in Ophiuchus and about 11 degrees east of the brighter M10/M12 globular cluster pair.
The best time of the year to observe M14 is during the months of May, June and July.
Mercury's long period of visibility for observers in the tropics and Southern Hemisphere comes to an end in April. The planet remains visible in the morning twilight sky towards the east, but only for the first two weeks of the month.
The best time to look for Mercury is at the start of April, when it appears highest in the sky. The planets altitude then decreases slightly each morning until it's finally lost to the bright twilight sky. During this time, Mercury brightens from magnitude -0.2 to -0.9. For observers at northern temperate latitudes, Mercury remains unsuitably placed for observation this month.
On April 26th, the planet reaches superior conjunction.
Although now fading in brightness, Venus continues to be visible as a brilliant morning object before sunrise. The planet starts the month at magnitude -4.4 and ends it at magnitude -4.1. Even at its faintest Venus is unmistakable; the planet dazzles above the horizon and is so bright that it's often reported as a hovering UFO!!
During April, Venus is best seen from the Southern Hemisphere and equatorial regions. From these locations, it's visible for more than three hours before sunrise. However, from northern temperate latitudes the planet remains low down and visible for only about one hour or so before sunrise.
The phase of Venus increases from 54 to 66% during the month and on April 25th, the waning crescent Moon passes 4 degrees north of the planet.
Mars reaches opposition in Virgo on April 8th and hence is visible all night. At magnitude -1.5, the planet is a wonderful red-orange beacon of light; positioned just a few degrees northwest of the brightest star in Virgo, blue giant Spica (α Vir - mag. +1.0). Not only is the "Red Planet" at its brightest for the year, but also has its largest apparent size, 15.2 arc seconds. Unfortunately, this is not a particularly favourable opposition. At the last great opposition in 2003, Mars reached magnitude -2.9 and displayed an apparent diameter of 25 arc seconds.
Mars can be a frustrating telescope object. When viewed through a 100mm (4-inch) telescope it appears small but under good seeing conditions it's possible to spot the polar cap as well as other major surface features such as Syrtis Major and various dusty shadings. Larger telescopes fair better with more subtle details visible.
On April 14, Mars is closest to Earth at 0.6176 AU (92.4 million kilometres or 57.4 million miles) distant and on the same day, the almost full Moon passes 3.5 degrees south of the planet.
Jupiter remains a beautiful early evening object during April. The "King of the Planets" is visible as soon as it's dark enough in the constellation of Gemini. Despite fading from magnitude -2.2 to -2.0 during the month, the planet is still brighter than Mars despite the latter reaching opposition in April.
With a current declination of 23 degrees north of the celestial equator, Jupiter favours observers located in the Northern Hemisphere. For example, from latitudes of northern Europe and North America, it remains visible until well after midnight at months end. However, from the Southern Hemisphere the visibility period is considerably less.
On April 6th, the first quarter Moon passes 5 degrees south of Jupiter.
Saturn is now moving retrograde among the faint stars of the constellation of Libra. The stunning "Ringed Planet" is heading towards next month opposition and is visible from early evening, remaining so for the rest of the night. During the month, Saturn brightens slightly from magnitude +0.4 to +0.2 with it apparent size increasing marginally from 18 to 19 arc seconds.
To the naked eye Saturn appears yellowish. Through a telescope the planets rings are a beautiful sight, visible with just a small instrument and currently wide open (tilted at 21.7 degrees). A medium sized telescope of 150mm (6-inch) or 200mm (8-inch) aperture will show a wealth of details including subtle planet formations, divisions in the rings as well as up to half a dozen of Saturn's satellites.
On April 17th, the waxing crescent Moon passes 0.4 degrees south of Saturn and an occultation is visible from South America.
M8 the Lagoon Nebula is a giant spectacular emission nebula in Sagittarius that's one of the brightest and finest star forming regions in the entire sky. With an apparent magnitude of +6.0, it's faintly visible to the naked eye and a wonderful sight through all types of optical instrument.
The nebula was discovered by Italian astronomer Giovanni Hodierna sometime before 1654. French astronomer Guillaume Le Gentil independently found it in 1747 before Charles Messier added the object to his catalogue on May 23, 1764. The distance to M8 is uncertain. It's currently estimated at 5,200 light-years although it might be as close as 4,100 light-years or as far away as 6,000 light-years.
When seen from our perspective this is an extremely large object. It covers 90 by 40 arc minutes of apparent sky, which is many times larger than the full Moon and comparable in size to another celebrated star forming region, the Great Orion Nebula (M42). To locate M8, start by finding the bright teapot asterism of Sagittarius. The top three stars of the teapot are Kaus Borealis (λ Sgr - mag. +2.8), Kaus Media (δ Sgr - mag. +2.7) and φ Sgr (mag. +3.2). Now imagine a line connecting φ Sgr to Kaus Borealis and extend it in a westerly direction - curving slightly southwards - for about 6 degrees until arriving at M8. The Trifid Nebula (M20) is located 1.5 degrees north of M8.
The Lagoon Nebula is best seen from southern and equatorial regions during the months of June, July and August.
M108 is a nice edge on barred spiral galaxy located in Ursa Major that was discovered by Pierre Méchain on February 19, 1781. It's not one of the objects included by Messier in his final published catalogue version but was added much later by Owen Gingerich in 1953. This was based on analysis of notes written by Messier and Méchain that referenced M108, suggesting that the object was intended for inclusion in a later version. William Herschel independently rediscovered M108 on April 17, 1789.
Locating M108 is easy since it's positioned only 1.5 degrees southeast of bright Merak (β UMa - mag. +2.3), the southwest corner star of the bowl of the famous Plough or Big Dipper asterism of Ursa Major. Located 50 arc minutes southeast of M108 is the planetary nebula "Owl Nebula" (M97) and both items fit easily in the same wide field telescope field of view.
M108 is best seen from Northern Hemisphere latitudes during the months of March, April and May. For observes located at latitudes greater than 35N, the galaxy is circumpolar and therefore never sets.
M107 is a loose eight-magnitude globular cluster located in Ophiuchus that's a difficult binocular object but much easier in small telescopes. It was discovered by Pierre Méchain in April, 1782 and then independently re-discovered by William Herschel on May 12, 1793. Herschel was also the first person to resolve M107 into stars. This cluster is one of the additional catalogue items that weren't included in Messier's final version but added much later by Helen Sawyer Hogg in 1947. She also added M105 and M106 since it seems probable that Méchain had also intended to include these items to a future edition of the catalogue.
The globular is located 20,900 light-years from Earth and spans 13 arc minutes of apparent sky, which corresponds to a spatial diameter of 80 light-years. It contains 100,000 stars and has an estimated age of 13.95 billion years, making it one of the oldest known globulars.
Locating M107 is relatively easy as its positioned 2.75 degrees southwest of zeta Oph (ζ Oph - mag. +2.5). This star is located 16 degrees north of Antares (α Sco - mag. +1.0) and can be also found by imagining a line connecting Yed Prior (δ Oph - mag. +2.7) with Yed Posterior (ε Oph - mag. +3.2) and extending it in a south-easterly direction for 9 degrees. The cluster is best observed during the months of May, June and July.
M12 is a magnitude +7.2 globular cluster in Ophiuchus that was discovered by Charles Messier on May 30, 1764. Messier was unable to resolve the cluster, describing it only as "nebula without stars". It was not until 1783 when William Herschel was the first to accomplish this task. Through good binoculars it appears as a faint hazy patch of light that's not well defined. Positioned nearby is the slightly brighter but similar looking globular M10. The two clusters are amongst the brightest of the seven Messier globulars located in Ophiuchus.
M12 is located in a barren area of sky that's devoid of bright stars and therefore finding it can initially require some patience. Start by locating Rasalhague (α Oph - mag +2.1) the brightest star in Ophiuchus. Join the stars of Ophiuchus in a curve heading westwards and southwards until arriving at two close together 3rd magnitude stars, Yed Prior (δ Oph - mag. +2.7) and Yed Posterior (ε Oph - mag. +3.2). M12 is located about 8 degrees northeast of these two stars. Positioned 3.25 degrees southeast of M12 is M10, with the star 30 Oph (mag. +4.8) located one degree east of M10.
The best time of the year to observe M12 is during the months of May, June and July.
April this year is a special time for astronomers as Mars the intriguing "Red planet" reaches opposition on the eighth of the month. On this day, Mars rises in the east as the Sun sets in the west, remains visible all night long before setting in the west as the Sun rises once again in the east. During April, the planet is also at its brightest and has its largest apparent size for the year. With a magnitude of -1.5, Mars is unmistakable amongst the stars of Virgo. The planet dazzles with a deep red-orange hue; shining at about the same brightness as Sirius, the brightest star in the night sky.
What makes a Mars opposition special is that they don't occur as often as the other outer planets. Generally speaking, Jupiter, Saturn, Uranus and Neptune reach opposition once per year. However, Mars takes roughly 2 years and 2 months or 780 days from one opposition to the next! The reason for this is due to orbital dynamics; Mars moves fast compared to the other outer planets and hence the Earth takes twice as long to catch up with it.
What to expect this year
The orbit of Mars is eccentric which means the difference in distance between its closest point to the Sun (perihelion) and its furthest (aphelion) is considerable. At perihelion Mars is 1.3815 AU (206.7 million kilometres or 128.4 million miles) from the Sun whereas at aphelion the distance increases to 1.666 AU (249.2 million kilometres or 154.9 million miles). This corresponds to an orbital eccentricity of 9.3%, compared to just 1.7% for the Earth. As a result, the brightness and apparent size of Mars at opposition greatly depend on the location of Mars in its orbit at that time.
Although better than the opposition of 2012, Mars in 2014 is closer to its aphelion orbital point than to its perihelion point. It presents an apparent disc of 15.2 arc seconds in diameter this year, which is slightly larger than the 13.9 arc seconds of 2012 but much less than the 25.1 arc seconds achieved at the historically close 2003 opposition. The next really great opposition of Mars will occur in 2018.
Mars always appears in the southern section of the sky during the best oppositions, favouring observers at southern latitudes. However, on this occasion the planet has a declination of -5 degrees and therefore is reasonably well placed for observers located at northern temperate latitudes as well. On April 14, closest approach to Earth occurs when 0.6176 AU (92.4 million kilometres or 57.4 million miles) separates the two planets.
M9 is a globular cluster located in the southern section of the large sprawling constellation of Ophiuchus. It was discovered by Charles Messier on May 28, 1764, who described it as a "nebula without star" of 3 arc minutes in diameter. With an apparent magnitude of +8.4, it's one of the fainter objects of its type in Messier's catalogue. Since not particularly bright M9 is a challenging object for binocular observers appearing at best as a slightly out of focus faint "star", which can be difficult to pick out against surrounding Milky Way stars. The cluster is much easier to spot with larger 15x70 or 20x80 binoculars but again not much detail is discernible.
M9 is located 25,800 light-years from Earth. At a distance of 5,500 light-years it's one of the nearer globular clusters to the center of the Milky Way Galaxy. The globular lies adjacent to a prominent dark nebula called Barnard 64, which significantly dims the light of the cluster due to intervening interstellar dust.
To find M9 start by locating Sabik (η Oph - mag. +2.4) the second brightest star in Ophiuchus. About 3 degrees southeast of Sabik is M9, which is best seen during the months of May, June and July.
M96 is an intermediate spiral galaxy 35 million light-years distant in the constellation of Leo. At magnitude +9.6, it's the brightest member of the Leo I or M96 group of galaxies that also contains M95, M105 and at least another 21 fainter galaxies. The grouping is one of many that lie within the Virgo Supercluster. The three galaxies are amongst the fainter objects in Messiers catalogue but all are visible with large 15x70 or 20x80 binoculars from a dark site, appearing as faint smudges of light.
M96 is an unusual galaxy in the sense that it has asymmetric arms and a displaced core that were probably caused by gravitational pulling from other nearby galaxies. It was discovered, along with M95, by Pierre Méchain on March 20, 1781. Charles Messier including both items in his catalogue four days later. M105 was not included in the original Messier catalogue but added much later by Helen Sawyer Hogg in 1947.
The galaxies are located in the southern middle section of the relatively large and bright constellation of Leo the Lion, which lies east of Cancer and to the west of Virgo. Leo contains one first magnitude star, Regulus (α Leo - mag. +1.4), which happens to be the brightest star in the surrounding region of sky. About 24 degrees east and two degrees north of Regulus is the third brightest star in Leo, Denebola (β Leo - mag. +2.1). Imagine a line connecting Regulus with Denebola with M95, M96 and M105 located just less than half way along this line. The northernmost member of the trio is M105 with M96 located 50 arc minutes south of M105 and M95 positioned 40 arc minutes west of M96.
The galaxies are best seen during the months of March, April and May.
M95 is a barred spiral galaxy about 36 million light-years away in the constellation of Leo. It was discovered by Pierre Méchain on March 20, 1781 - the same night he discovered M96 - and catalogued by Charles Messier four days later. With an apparent magnitude of +10.3 it's visible in small telescopes. Together with M96 and M105, M95 forms a trio of faint gravitationally bound galaxies grouped close together. Of these, M96 is the brightest and the largest. The group is known as the Leo I or M96 group of galaxies, which also contains at least 21 other fainter galaxies and is one of many groups that lie within the Virgo Supercluster.
Charles Messier included M95 and M96 in his catalogue on the March 24, 1781. M105 was not included in the original Messier catalogue but added much later by Helen B. Sawyer Hogg in 1947. The galaxies are best seen during the months of March, April and May.
M109 (NGC 3992) is a barred spiral galaxy located in the constellation of Ursa Major. It's estimated to be located 83.5 Million light-years from Earth, making it the furthest object in Messier's catalogue. Despite its large distance it's relatively bright; with an apparent magnitude of +10.3 the galaxy is within the range of small to medium sized amateur telescopes.
M109 has a complicated history. In March 1781, Pierre Méchain passed three nebulae he recently found to Charles Messier for confirmation. The first one was to become M97 while the others were recorded by Messier as objects 98 and 99 in a rough draft. However, Messier never assigned positions for these items in the main catalogue and hence they were never included in the final version. Many years later in 1953, American astronomer and historian Owen Gingerich added draft objects 98 and 99 to the "official" Messier catalogue and they became items M108 and M109. The story is further complicated by recent analysis that suggest Méchain may have not originally observed NGC 3992 but instead nearby galaxy NGC 3953. If so, this implies that Messier in fact discovered NGC 3992 and not Méchain. Despite this, it's generally accepted that M109 is identified as NGC 3992.
Finding M109 is easy; it's located only 0.75 degrees to the southeast of Phecda (γ UMa - mag. +2.4) one of the stars of the Plough asterism of Ursa Major. The galaxy is best seen from northern temperate latitudes during the months of March, April and May. From the Southern Hemisphere it never rises very high above the northern horizon.
M23 is a pretty open cluster that's located in the rich starfields of the Sagittarius Milky Way. With an apparent magnitude of +6.9 it's beyond naked eye visibility but is a superb binocular object and a glorious sight through small telescopes. This vast cloud of about 150 stars is located 2,150 light years from Earth and has an actual diameter of about 20 light years. With an estimated age of at least 220 million years old, it's one of the galaxy's older open clusters.
M23 was discovered by Charles Messier on June 20, 1764. It can be easily found just northwest of the "teapot" asterism of Sagittarius. The three stars that form the top of the teapot are φ Sgr (mag. +3.2), Kaus Borealis (λ Sgr - mag. +2.8) and Kaus Media (δ Sgr - mag. +2.7). Positioned 6 degrees northwest of Kaus Borealis is mag +3.8 star μ Sgr. M23 can be found 4.5 degrees northwest of this star and approximately on a line connecting it with ξ Ser (mag. +3.5). Located 5 degrees east of M23 is M24, the very large Sagittarius Star Cloud.
M106, mag. +8.5, is a large spiral galaxy located in Canes Venatici that was discovered by Pierre Méchain in July 1781. He described the galaxy in little detail; referring to it only as a nebula close to star 3 CVn. William Herschel then rediscovered it on March 9, 1788. Since Herschel was using a better telescope than Méchain he was able to see much more detail and noted it as "very brilliant with a bright nucleus and faint milky branches north preceding and south following." Although not one of Messiers original catalogue entries, M106 was included, along with M105 and M107 in 1947 by Helen Sawyer Hogg. It seemed reasonable to assume that Méchain had already intended to add these objects to a future edition.
M106 is one of the brightest examples of a Seyfert type II galaxy and is therefore strong in X-rays and unusual emission lines, which are believed to result from sections of the galaxy falling into the supermassive black hole located at the centre. American astronomer Carl Seyfert first identified this class of object in 1943.
The galaxy is located towards the northwestern corner of Canes Venatici; a faint constellation with only one star Cor Caroli (α CVn - mag. +2.9) that's brighter than magnitude +4.0. However, locating M106 is not difficult as the Plough or Big Dipper asterism of Ursa Major is positioned just to the north and can be used as a starting point. Once found, focus on Megrez (δ UMa - mag. +3.2) the faintest star of the Plough. Positioned 5.5 degrees south and slightly east of Megrez is 5 CVn (mag. +4.8). M106 is located just over 4 degrees south of 5 CVn with star 3 CVn (mag. +5.3) positioned along the line connecting the two.
M106 is best seen from the Northern Hemisphere during the months of March, April and May. From southern temperate latitudes it's a difficult object as it never rises very high above the northern horizon.
Mercury reaches greatest elongation west on March 14th (28 degrees) and as a result is well placed as an early morning object throughout March for observers located in the Southern Hemisphere and tropics. This also happens to be the most favourable morning apparition of the year from the Southern Hemisphere.
Mercury's period of visibility during this particular apparition is considerable; it extends from the end of February until the middle of April. At the end of last month Mercury appeared as a faint tricky object low down above the eastern horizon just before sunrise. The situation quickly improves during March with the planet increasing from magnitude +0.8 on March 1st to magnitude +0.1 by March 14th (the date of greatest elongation west) when Mercury appears highest in the morning sky. For example, from latitude 35S (approx. equal to Sydney, Cape Town and Santiago), Mercury will appear 17 degrees above the eastern horizon 45 minutes before sunrise. It should also be noted that once past greatest elongation west, Mercury continues to brighten as it begins to draw into the Sun. The planet doesn't reach maximum brightness (mag -1.0) until the very end of the visibility period, more than 4 weeks after greatest elongation west!
As March progresses, Mercury brightens from magnitude +0.8 to -0.2 with the phase of the planet increasing from 28 to 76 degrees. Dichotomy or half-phase occurs on March 11th, when the planet is 50 percent illuminated. On March 19th, Mercury reaches aphelion and is located 0.467 AU (approx. 69.9 million km or 43.4 million miles) from the Sun.
Unfortunately, from northern temperate latitudes the angle of the ecliptic is not favourable and the planet remains low down and unsuitably placed for observation during March.
Venus reaches greatest elongation west (47 degrees) on March 22nd and remains a brilliant object in the early morning skies during March. From the Southern Hemisphere the planet can be seen towards the east for approx. 3 hours before sunrise. Despite fading from magnitude -4.6 to -4.3 during March, unmistakable Venus shines like a dazzling beacon. This brightest of all planets can even be followed with the naked eye for a short time after the Sun has risen above the eastern horizon.
From northern temperate latitudes Venus is visible for less than two hours before sunrise, appearing low down above the east-southeast horizon. The illuminated phase of Venus increases from 37 to 54 percent during March with dichotomy or half-phase occurring on March 23rd.
On March 27th, the waning crescent Moon will pass 4 degrees north of Venus.
Mars is now a beautiful late evening object that's located in Virgo. The fourth planet from the Sun is named after the Roman god of war and appears to the naked eye striking red-orange in colour. With not long to go before opposition (April 8th), Mars brightens rapidly as the month progresses. It starts March at magnitude -0.5 just to the northeast of Spica (α Virgo - mag. +1.0) before ending the month at magnitude -1.3 and five degrees directly north of the star.
On March 1st, Mars reaches its first stationary point after which it begins retrograde motion. The planet continues to move this direction until May 21st when it reaches its second stationary point and following that direct motion is once more resumed.
As well as rapidly brightening this month, the apparent size of Mars also increases from 11.6 to 14.6 arc minutes. When viewed through a small telescope Mars appears small but under good seeing conditions it's possible to spot major surface features such as the North Pole cap, Syrtis Major and other dusty markings. Don't be afraid to push up the magnification as high as possible to bring out those subtle details.
On March 19th, the waning gibbous Moon passes 3 degrees south of Mars.
Jupiter is now two months past opposition and although currently fading in brightness and apparent size it remains a brilliant object in Gemini. The planet is visible shortly after sunset and remains so until after midnight for northern-based observers, although the period of visibility is considerably less for those located further south.
At the start of the month, Jupiter continues its retrograde motion until March 6th when it reaches its second stationary point. After this, direct motion is again resumed. This also represents the end of this year's opposition period. On March 1st, Jupiter shines at magnitude -2.4 with an apparent diameter of 42 arc minutes. At the end of the month the brightness has decreased to magnitude -2.2 and the apparent diameter to 39 arc minutes.
On March 10th, the waxing gibbous Moon (68% illuminated) passes 5 degrees south of Jupiter.
Saturn, mag +0.6, is located in Libra and also reaches a stationary point this month. Like Mars, the beautiful ringed planet reaches its first stationary point (on March 3rd), which signals the change in motion from direct to retrograde. As a result, Saturn will appear to move little against the "fixed" background stars this month. By the end of March, Saturn is rising before midnight for observers in northern temperate latitudes and a couple of hours earlier for those further south.
Of course the rings of Saturn are its most famous feature and even a small telescope will show them. Through medium and large aperture amateur scopes they are a fantastic breathtaking sight. In addition to the rings a handful of Saturn's moons are also visible. The largest and brightest moon Titan shines at eight magnitude and is visible with binoculars. In addition, a medium size scope will also show Rhea, Tethys, Dione, and Iapetus.
On March 21st, the waning gibbous Moon passes 0.2 degrees south of Saturn and an occultation is visible from the South Atlantic at 3:18 UT.
M20 is the famous Trifid Nebula, a bright colourful emission and reflection nebula that's located in the constellation of Sagittarius. At magnitude +6.3, it's visible with binoculars. This remarkable object not only contains an emission and reflection nebula but also a dark nebula and an embedded open star cluster. When photographed or imaged, it looks spectacular with the emission nebula appearing red, the reflection nebula blue and mixed in between numerous dark lanes. The dark lanes appear to cut through the nebula splitting it into three prominent sections hence the popular name Trifid; meaning 'divided into three lobes'.
The much larger and brighter Lagoon Nebula (M8) is located two degrees south of M20 with tightly packed open cluster M21 positioned 0.75 degrees northeast of M20.
Charles Messier discovered both M20 and M21 on June 5, 1764. He referred to M20 as an envelope of nebulosity. The surrounding area of sky is the richest part of the Milky Way; here you are looking towards the direction of galactic centre hence the abundance of stars, open clusters, globular clusters and nebulae. This wonderful region is perfect to scan with binoculars or small telescopes, especially at low magnifications.
To locate the Trifid, first focus on the bright familiar teapot asterism of Sagittarius. The top three stars of the teapot are Kaus Borealis (λ Sgr - mag. +2.8), Kaus Media (δ Sgr - mag. +2.7) and φ Sgr (mag. +3.2). Imagine a line connecting φ Sgr to Kaus Borealis and then extending it for just over 6 degrees to arrive at M20. The Trifid is best seen from southern and equatorial regions during the months of June, July and August.
M54 is a globular cluster located in Sagittarius that’s a staggering 87,400 light years from Earth. It was discovered by Charles Messier on July 24, 1778 and was for many years thought to be part of the Milky Way but is now believed to belong to the nearby Sagittarius Dwarf Elliptical Galaxy. It owns the distinction of being the first extragalactic globular cluster ever discovered, even though it wasn't recognized as such for over 200 years. Despite its vast distance, M54 is visible in binoculars albeit faintly (mag. +7.9). The fact that it can be seen in binoculars at all from such a distance is incredible and is due to its large intrinsic size and high absolute brightness. With a diameter of over 300 light-years diameter, this globular is enormous and one of the largest known.
Finding M54 is easy as it lies within the teapot asterism of Sagittarius. The starting point is to focus on the base of the teapot and image a line connecting Ascella (ζ Sgr - mag. +2.6) with Kaus Australis (ε Sgr - mag. +1.8). Positioned about 1.75 degrees along this line and slightly north is M54. With a declination of -30 degrees, the globular is best seen from the Southern Hemisphere during the months of June, July and August. From northern temperate latitudes, it’s a much more difficult target as it never rises very high above the southern horizon.