Vega is a brilliant magnitude +0.03 blue-tinged white main sequence star located in the constellation Lyra. Its marginally brighter than Capella (α Aur - mag. +0.08) and slightly fainter than Arcturus (α Boo - mag. -0.04) making it the second brightest star in the northern section of the sky. With a declination of 38 degrees north, Vega appears high in the sky and even overhead from northern temperate latitudes. The star is visible at sometime or another from anywhere north of 51 degrees south and therefore can been from the majority of Southern Hemisphere including all of Australia, New Zealand, South Africa and most of Argentina and Chile.
Vega is a dazzling beacon of light amongst the relatively faint but prominent constellation of Lyra. It was originally named Wega from a derivative of the Arabic phrase "Al Nasr al Waqi" or Swooping Eagle. Around 12,000 BC, Vega was the North Pole star and will return there again around 13,700 AD. It's probably unsurprising given its brilliance and prominent northern position that Vega is one of the most investigated of all stars. It was one of the first stars to have its distance determined by parallax and was the first star other than the Sun to be photographed and have its spectrum determined. Vega also makes up the brightest corner of the well-known Summer Triangle, along with Altair (α Aqr - mag. +0.77) and Deneb (α Cyg - mag +1.25). This bright asterism was popularised by American author H.A. Rey and British astronomer Sir Patrick Moore in the 1950s.
Vega is a spectral class A0Va star that's positioned within the main sequence of the Hertzsprung-Russel diagram. It's a nearby star that's only 25 light-years distant and relatively young at 455 million years, equal to about 1/10 the age of the Sun. However, Vega is burning through its hydrogen fuel at a much faster rate than our star and is expected to start becoming an M class red giant in another 500 million years. For comparison, the same scenario will not happen to the Sun for over 5 billion years! Even though it's more than twice as massive as the Sun and over 40 times more luminous, Vega is not massive enough to explode as a supernova and will end its life, just like the Sun, as a white dwarf. Visible in amateur scopes are two faint companions at magnitude +9.5 and +11.0, although both are unrelated and much further away than Vega.
Recent observations suggest that the star is slightly variable and of the Delta Scuti type and if confirmed it would be the brightest example of this type. Surrounding Vega are disks of dust and debris extending for hundreds of astronomical units (AU).
The charts below show the position of Vega. It's best seen during the months of June, July and August.
A total lunar eclipse takes place on April 4, 2015 and is visible from western North America, the Pacific, East Asia, Australia and New Zealand. A lunar eclipse occurs when the Moon passes within Earth's shadow (umbra) resulting in a darkening or reddening of its appearance. The Moon doesn't usually disappear completely due to scattering of sunlight by the Earth's atmosphere.
Eclipses of the Sun and Moon occur in pairs. When a solar eclipse occurs, a lunar eclipse takes place either before or after with this lunar eclipse following last month's solar eclipse. The partial phase begins at 10:15:45 UT with totality reached at 11:57:54. The duration of totality is short on this occasion; it lasts just 4 minutes and 43 seconds. Once totality ends the partial stage again resumes, ending at 13:44:46 UT.
Unlike a total eclipse, which can only be seen from a very narrow band across the Earth, a total lunar eclipse can be seen from any place where the Moon is above the horizon. The charts below show the visibility of the upcoming lunar eclipse.
Betelgeuse is a red supergiant in Orion that's one of the most famous stars in the sky. It's an irregular variable that usually fluctuates between magnitudes +0.3 and +0.8, though on rare occasions its been known to peak at magnitude 0.0 and dim down to magnitude +1.2. The star currently hovers around magnitude +0.42 and marks the upper left-hand corner of the ancient hunter figure.
Although lettered alpha (α) Orionis, Betelgeuse is usually fainter than Rigel (β Orionis - mag. +0.13) and therefore the constellations second brightest star. The first person to record brightness fluctuations was Sir John Herschel in 1836 and on two occasions, in October 1837 and November 1839, he observed it to be brighter than Rigel. At best, Betelgeuse is comparable in brightness to Rigel and Capella (α Aur - mag. +0.08) but at the opposite end of the scale it appears more like Aldebaran (α Tau - mag(v). +0.75->+0.85).
The stars name is Arabic and is derived from "Ibt-al-Jauza", which means "the shoulder of the central one". It's often alternatively written as Betelgeuze or Betelgeux and pronounced in a number of ways; many people refer to it as "Beetlejuice", though "Beteljerze" is closer to the original Arabic. Eminent English 19th century astronomer William Lassell - who discovered Neptune's largest moon Triton, Saturn's moon Hyperion (co-discovered) and Uranus moons Ariel and Umbriel - described Betelgeuse majestically as "A most beautiful and brilliant gem; a rich topaz in hue and brilliancy different from any other star I have ever seen!".
As with all M type stars the surface temperature of Betelgeuse is much cooler than the Sun; about 3,400 K compared to 5,800 K. The star is truly enormous in size with a diameter that could be as large as 1.67 billion kilometers (1.04 billion miles) or about 1200x that of the Sun. If placed at the centre of the Solar System it would easily contain the orbits of Mercury, Venus, Earth and Mars. However, Betelgeuse is much less denser that the Sun and therefore only between 8 to 20 times more massive. It's also likely that the star has used up its supply of hydrogen and is now fusing helium at its core. Eventually, it will explode as a supernova and that will be a spectacular event. The explosion will temporarily shine as bright as a crescent Moon, cast strong shadows on the ground and easily be visible in daylight. It could go bang tomorrow but we may have to wait another million years or so...only time will tell.
Betelgeuse is located 640 light-years distant and is the nearest of the vast red supergiants. As a result, it was the first star to be directly imaged by the Hubble Space Telescope in 1995; angular size is 0.05 arc seconds. The star is about 10,000x more luminous than the Sun. The chart below shows its position in Orion. Since located just north of the celestial equator it can be seen from every permanently inhabited location in the World. The best months are December, January and February. It appears overhead or near overhead from tropical regions.
A new 6th magnitude nova that was discovered in Sagittarius on March 15th by John Seach of New South Wales, Australia brightened quickly to magnitude +4.3 on March 22nd. On this day it could be easily seen with the naked eye and was bright in binoculars. Although now fading, the nova should remain within amateur range for days if not weeks to come. On March 24th, it stood at magnitude +5.5.
Novae are out-bursting stars. They occur when a compact white dwarf star accretes so much material from a close companion that it undergoes a thermonuclear explosion on its surface. This leads to a brief dramatic sudden increase in brightness. They are different to supernovae, where a catastrophic destructive event is caused by the collapse of the core of the star.
The finder chart below shows the position of the nova. It's located in the northern part of the middle section of the famous Sagittarius "teapot" asterism. It has been designated as Nova Sagittarii 2015 No. 2.
The Seated Queen
Cassiopeia is a prominent northern constellation named after Queen Cassiopeia, the wife of King Cepheus of Ethiopia. In Greek mythology the Queen was arrogant and extremely boastful about her beauty. Legend has it she claimed her and daughter Andromeda were more beautiful than all the Nereids, the nymph-daughters of the sea god Nereus. This brought the wrath of the ruling god of the sea Poseidon who decided to destroy the kingdom.
After consulting a wise oracle, the only way the King and Queen could stop Poseidon from carrying out his threat was to scarify Andromeda. The princess was left helplessly chained to a rock at the sea edge awaiting her fate at the hands of Cetus, the sea monster. However, just in time the hero Perseus arrived saved Andromeda and in the process killed the sea monster. Although Andromeda lived to marry Perseus, Poseidon deemed that Cassiopeia should not escape punishment and banished her forever to the sky, tied to the chair of torture!
The constellation is one of the original 48 plotted by second century astronomer Ptolemy and remains as one of the 88 modern constellations. It's one of the most recognisable constellations due to the distinctive "W" shape of its five brightest stars. This asterism forms part of the chair and consists of γ Cas (mag.(v) +1.6 -> +3.0), Schedar (α Cas - mag. +2.24), Caph (β Cas - mag. +2.28), Ruchbah (δ Cas - mag. +2.66) and ε Cas (mag. +3.35). Variable star γ Cas can peak at magnitude +1.6 hence making it easily the brightest member of the group, but currently it hovers around magnitude +2.15.
Since located right bang at the centre of the rich northern Milky Way, Cassiopeia is full of wonderful deep-sky objects. It contains of over a dozen bright open clusters visible in small scopes. In addition, there are also some beautiful double stars and interesting variable stars. At Cassiopeia's southern end are three faint galaxies, two of which are dwarf ellipticals and members of the M31 Group. For larger scopes there are four faint nebulae.
From most northern temperate latitudes Cassiopeia is circumpolar and therefore visible all year round. It appears highest in the sky during October, November and December. From Southern Hemisphere latitudes the constellation appears low above the northern horizon or never even rises at all. Positioned on the opposite side of the North Celestial Pole is another famous constellation, Ursa Major "The Great Bear".
Cassiopeia is bordered by Andromeda to the south, Perseus to the southeast and Cepheus to the north. The famous supernova outburst of 1572, observed by Tycho Brahe, occurred near the star kappa (κ) Cas. The remains of another supernova, which erupted around 1660 but went unseen at the time, forms the brightest extrasolar radio source Cassiopeia A. It lies near open cluster M52.
Bright Star, Variable Star, Double Star
Gamma Cas (γ Cas) - a remarkable blue giant variable star known as a "shell star". Rotating at high speed the star is partly unstable, ejecting rings of material at irregular intervals. This behaviour causes it to vary unpredictably between magnitudes +1.6 and +3.0. It currently shines at magnitude +2.15 and therefore marginally the constellation's brightest star.
Gamma Cas is the middle star of the "W" and is located 613 light years from Earth. Unusual for a bright star it has no traditional Arabic or Latin name. However, in Chinese it has the name Tsih meaning "the whip". It was also given the nickname Navi by American astronaut Gus Grissom who used it for navigational purposes.
The star is a spectroscopic double with an orbital period of about 204 days. It's also a very challenging optical double with a faint 11th magnitude yellow-white (F6) dwarf companion; separation 2.1 arc seconds. Splitting the pair requires decent aperture, steady seeing conditions and quite high magnifications. A minimum 250mm (10-inch) scope is recommended.
Gamma Cas is 70,000 times more luminous than the Sun and is surrounded by two faint reflection nebulae, IC 59 and IC 63.
Bright Star, Double Star
Schedar (alpha Cas - α Cas) - is a magnitude +2.24 orange giant star located 228 light years distant. It has a wide (mag. +8.9) unrelated companion that's visible at low magnifications in small telescopes. The separation is 65 arc seconds. A couple of centuries ago observations thought that Schedar was variable in nature but recent measurements have determined no such variations.
Caph (beta Cas - β Cas) - is the far western star of the "W" asterism. It's a white (F2) Delta Scuti type variable that shines at magnitude +2.28 and almost identical in brightness to Schedar. Although variable the range is very small and changes in brightness can't readily be noticed with the naked eye. At peak brightness Caph reaches magnitude +2.25, at minimum slightly dimmer at magnitude +2.31.The period is only 2.5 hours.
Delta Scuti type variable stars are subgiant or main sequence stars between 1.5 and 2.5 times more massive that the Sun within the spectral class range A0 to F5. They are nearing the end of their hydrogen fusion lifetime and as a result exhibit a slight pulsating effect resulting in a small brightness variation. Of the known Delta Scuti variables, only Altair (α Aqr - mag. +0.77) is brighter than Caph.
Caph is also a spectroscopic binary star with a faint companion. The orbital period is 27 days but little else is known about its companion. The system is located 54 light-years from Earth.
Ruchbah (Delta Cas - δ Cas) - is another slightly variable star in the "W". It's an Algol-type eclipsing binary star that fluctuates between magnitudes +2.68 and +2.74 over a period of 759 days. Ruchbah is located 99 light years distant and telescopically it appears as single blue-white star. It's the second most eastern star of the "W".
Epsilon Cas (Ε Cas) - mag. +3.35, is a blue-white B type giant star located 440 light years from Earth. It forms the eastern star of the "W" and is also the faintest of the five.
Epsilon Cas has the traditional name Segin and is more than 2,500 times more luminous than the Sun.
Multiple Stars, Double Stars
Achird (Eta Cas - η Cas) - is a beautiful double star for small telescopes. It consists of a magnitude +3.4 yellow G2 star similar to the Sun and a fainter orange-red K class dwarf secondary star of magnitude +7.5. They are separated by 13 arc seconds. A small 80mm (3.1-inch) scope at 80x magnification will easily split them. Both stars are classified as an RS Canum Venaticorum variables. They fluctuate very slightly (0.05 magnitudes) due to active chromospheres.
At a distance of 19.4 light years from Earth, Achird is the nearest Cassiopeia star to us.
Iota Cas (ι Cas) - is an impressive triple star located 142 light years from Earth. A 100mm (4-inch) scope at about 120x magnification easily reveals a white primary star of magnitude +4.6 along with a wide fainter red star of magnitude +8.5, separated by 7.3 arc seconds. More difficult but also visible is the closer yellow star of magnitude +6.9 (separation 2.8 arc seconds from the primary).
The triple system may just be a chance alignment. However, the main star is itself a spectroscopic binary.
Psi Cas (ψ Cas) - another multiple star in Cassiopeia. Although not as impressive as iota Cas it's a nice target for medium size scopes. It consists of a magnitude +4.7 orange primary star with a magnitude +9.0 wide companion, which itself is a double. The separation between the primary and faint pair is 20 arc seconds. The faint pair consists of white stars of magnitudes +9.4 and +10.0, separated by 2.9 arc seconds. The primary itself has a very faint close companion (14th mag.) making this a quadruple system. It's 193 light years distant.
Although not visually spectacular, the three brightest members are visible in medium size scopes. A 200mm (8-inch) scope at about 200x should show them all.
Sigma Cas (σ Cas) - is located 1 degree southwest of open cluster NGC 7789. Sigma Cas consists of magnitude +5.0 and +7.1 components separated by 3 arc seconds. It's a challenging double for owners of 80mm (3.1-inch) scopes but relatively easy with a small increase in aperture. With a magnification of about 150x, a 150mm (6-inch) scope will easily split them and on nights of good seeing smaller scopes should also do the job.
Sigma Cas is located 1,500 light years distant.
Rho Cas (ρ Cas) - is a rare yellow hypergiant star and one of the most luminous stars in the galaxy. Rho Cas is half a million times more luminous than the Sun and has a diameter of 630 million kilometers. To give an idea of it's enormous size; if the star were at the centre of our Solar System, it would be larger enough to completely swallow Mercury, Venus, Earth and Mars, and almost reach the orbit of Jupiter!
Rho Cas is classified a semi-regular pulsating variable star with a minimum magnitude of +6.2 and a maximum magnitude of +4.1. The period is approximately 320 days and it can be seen with the naked eye when towards the brighter end of the range. It's located 8,200 light years from Earth.
Open cluster NGC 7789 is positioned 1.5 degrees southeast of rho Cas.
V509 Cas - although only around a dozen yellow hypergiant stars are known in the Milky Way there is another example in Cassiopeia, V509. This star is slightly smaller and less luminous than Rho Cas, but still incredibly powerful and large in its own right. It varies between magnitudes 4.6 and 5.2 over a period of about a year.
R Cas - is a long period variable star of the Mira type that changes between magnitudes +4.7 and +13.5 over a period of 430.5 days. At its brightest it's visible to the naked eye and easily seen with binoculars. The star is positioned at the southwestern part of the constellation and is located 410 light years from Earth.
RZ Cas - is an Algol type variable for binocular and small telescope observers. It varies between magnitude +6.2 and +7.7 over a period of 28.7 hours.
YZ Cas - another Algol type variable for binocular and small telescope observers. The brightness variation (mag. +5.7 -> +6.1) is not as large as RZ Cas and therefore more challenging. It has a period of 4.47 days.
YZ also has a faint magnitude +10.5 wide companion separated by 36 arc seconds.
NGC 457 - at magnitude +6.4, NGC 457 is the brightest open cluster in Cassiopeia and one of the finest examples in the northern sky. Since not a Messier item it's often overlooked and therefore not as well known as other bright clusters. However, it's a stunning object with the main stars arranged in curves resembling an Owl shape, hence the popular name "the Owl Cluster".
NGC 457 is just beyond naked-eye visibility. The brightest star inside is Phi Cas (φ Cas - mag. +5.0), which can be seen with the naked eye but it's not a true member. Together with another 7th magnitude foreground star they form the Owl's bright eyes.
Binoculars easily show the two brightest stars immersed in a cloud of just about resolvable nebulosity. A small 80mm (3.1-inch) scope reveals tens of mainly white stars. The notable exceptions are the brightest two stars, which appear yellow and blue in colour. With medium and larger scopes many dozens of stars spread over 20 arc minutes of apparent sky are visible.
NGC 457 is located 7,900 light-years distant and is estimated to be 21 million years. It's also known as Caldwell 13.
NGC 129 - is a beautiful mag. +6.5 cluster located midway between Caph and gamma (γ) Cas. This sparkling group contains at least 35 stars with the brightest members being of 8th magnitude and visible in binoculars. The cluster is a fine telescope object with many dozens of stars visible arranged in chains across a diameter of 21 arc minutes.
NGC 129 is 9,900 light years distant and estimated to be 76 million years old. It was discovered by William Herschel on December 16, 1788.
NGC 7789 - is a superb open cluster for medium or large size telescopes. It's located 3 degrees southwest of Caph and about halfway between stars rho Cas and sigma Cas.
The cluster is one of the richest clusters in the sky, consisting of at least 300 faint stars spread across 15 arc minutes of sky. At mag. +6.7 it appears as a faint hazy patch of light in binoculars. Telescopically, NGC 7789 is a treat. A 200mm (8-inch) scope shows dozens of faint stars extending into the hundreds with larger instruments. It gives the appearance of a loosely populated globular cluster.
It's located 7,600 light-years distant.
NGC 663 - mag. +7.1, is a prominent open cluster well suited for telescopes. It contains at least 80 stars visible in amateur scopes spread over a diameter of 16 arc minutes with the brightest cluster members visible with binoculars. A 100mm (4-inch) scope reveals a bright rich open cluster with many stars visible, immersed in a hazy glow. The cluster is striking in large scopes where dozens of stars can be seen across the cluster face. It's more concentrated towards the centre.
The cluster is located 3 degrees northeast of Ruchbah and 3 degrees southwest of epsilon (ε) Cas. Next to it are clusters NGC 654 and NGC 659 and M103.
NGC 663 is located 7,000 light years distant. It's also known as Caldwell 10.
IC 1805 - is a large scatted bright mag. +6.5 open cluster located in eastern Cassiopeia. Its positioned 8 degrees east of Ruchbah and about 4 degrees north-northeast of the "Double Cluster" (NGC 869/884) in Perseus. IC 1805 is located just over 1 degree directly west of NGC 1027 with small cluster IC 1848, 2.5 degrees southeast of IC 1805. This part of the sky is an excellent region for scanning with binoculars. Also surrounding the three clusters is a network of faint nebulosity that's difficult to detect visually, even with large amateur scopes.
The cluster contains about 40 stars spread over 22 arc minutes. The brightest members are 8th magnitude. IC 1805 is visible in binoculars. It appears like a detached part of the Milky Way with the brightest stars resolvable. In small and medium scopes it's a nice object that's fully resolvable.
NGC 1027 - another fine binocular and small telescope open cluster is NGC 1027. Located in the same region of sky as IC 1805 and IC 1848, this cluster is similar in size and appearance to IC 1805 only slight fainter at mag. +6.7. It also contains 40 members.
IC 1848 - mag. +6.5 is the last of our eastern Cassiopeia open clusters. Although not as impressive as its two neighbours, it contains only 10 stars and about half the size, the cluster is easily visible with binoculars and small scopes.
M 52 - is located towards the constellations western boundary. This is the brightest of Cassiopeia's two Messier clusters and a fine northern Milky Way cluster. Shining at magnitude +7.2, it's easily visible in binoculars appearing as a somewhat fan or "V" shaped haze with a prominent 8th magnitude yellow star positioned at the southwest corner. Small scopes reveal some fainter stars sprinkled across the diameter of the cluster. In larger scopes, M52 is a wonderful sight with dozens of stars visible.
In total, M52 contains 200 stars spread across 13 arc minutes of sky. It's located between 3,000 and 7,000 light-years distant and estimated to be 35 million years old. The emission nebula NGC 7635 (the Bubble Nebula) is one degree southwest of M52.
NGC 225 - mag. +7.0, is a loose open cluster consisting of 20 stars spread across 12 arc minutes of sky that's visible in binoculars. Telescopes reveal stars of similar brightness without any particularly great concentration.
NGC 225 was nicknamed the "Sailboat Cluster" by Rod Pommier.
M 103 - is a small open cluster positioned 1 degree east of Ruchbah (δ Cas). It contains at least 40 members with a combined magnitude of +7.4. The stars are packed into a small area just 6 arc minutes across, which is equivalent to 1/5th the diameter of the full Moon. M103 is too faint to be seen with the naked eye but easily visible in binoculars, appearing like a faint wedge of light. Through a 100mm (4-inch) scope it's brightest four stars are resolvable and shaped like the Greek letter lambda (λ). With averted vision a nebulous triangular patch of light is revealed that extends beyond the brightest stars.
A 7th magnitude star (Struve 131) is the stand out star in the group but it's not a true member. This is an interloper, a star that's closer to us and just happens to be in the line of sight. Struve 131 is also a multiple star that's easily split in small scopes.
M103 is located 10,000 light years distant. A few degrees east of it are open clusters NGC 654, NGC 659, Trumpler 1 and NGC 663. The latter is occasionally confused with M103.
NGC 659 - half a degree southwest of NGC 663 is magnitude +7.9 cluster NGC 659. This is small and compact with about 40 stars crammed into 5 arc minutes of apparent sky. It appears in binoculars as very small faint patch of light that best seen with averted vision. Also visible in the same binocular field of view are NGC 663, NGC 654, Trumpler 1 and M103.
Through a 200mm (8-inch) scope, NGC 659 appears almost circular with at least 15 stars visible with direct vision and many more with averted vision. It's a wonderful sight.
NGC 654 - is located 0.75 degrees north of open cluster NGC 663. Like NGC 659 this is a small compact cluster with 60 stars across 5 arc minutes. It shines at magnitude +6.5 although often described as looking fainter than NGC 663. The dominant star is a magnitude +7.3 star towards the cluster southeast, which is easily visible with binoculars. At 100x magnification a 150mm (6-inch) scope reveals at least 40 stars configured in streams that look like a "V" shape.
Trumper 1 (Tr 1) - is the first entry in a catalogue of star clusters compiled by America astronomer Robert Trumpler during the 20th century. It's a small cluster of 20 stars spanning 4.5 arc minutes of sky. Trumpler 1 has a combined magnitude of +8.1 with the member stars being of 10th magnitude or fainter. Although faintly visible in binoculars it appears nothing more than a slightly denser clump of the surrounding Milky Way. Telescopes reveal a sprinkling of faint stars.
One of the great natural events takes place on March 20, 2015 when a total solar eclipse is visible from the North Atlantic. This time, the narrow band of totality streaks across a path that starts in the ocean just south of Greenland, touches land in the Faroe Islands and Svalbard before finally ending at the North Pole. A partial eclipse is visible in Europe, North Africa and North and East Asia.
A solar eclipse occurs when the Moon passes between the Earth and the Sun, thereby totally or partially obscuring the Sun's image for an observer on Earth. Total eclipses are only possible due to a piece of nature's luck. By sheer coincidence the Sun is about 400 times larger in size than the Moon but also about 400 times more distance and therefore to the observer on the ground, both the Sun and the Moon present about the same (apparent) size in the sky. The apparent size or diameter of the Sun and the Moon do exhibit small variations; at times the Moon appears slightly larger in the sky than the Sun and vice-versa.
A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun and blocks all direct sunlight, turning day into darkness. This path of totality occurs inside a narrow band that touches the surface of the Earth. It has a maximum width of only 267 kilometres (167 miles). On the other hand, for a partial solar eclipse the shadow is many thousands of kilometres wide and the partial eclipse is visible over a much larger region.
Eclipse Path on March 20, 2015
The diagrams below shows the visibility of this eclipse and the path of totality (Moons umbral shadow). The only populated places where the totality can be seen and can be reached by public travel are the Faroe Islands and Svalbard. The longest duration of totality is 2 minutes 46 seconds off the coast of the Faroe Islands at 9:46 UT. From the Faroe Islands capital city Torshavn, 2 minutes 2 seconds of totality occurs at 9:42 UT. Totality occurs 30 minutes later at 10:12 UT from Svalbard and lasts for 2 minutes and 25 seconds.
The penumbral shadow of the Moon (partial part of the eclipse) is visible over a much greater region. For example, Scotland and northern parts of England will experience at least a 90% partial eclipse, London an 84% partial eclipse and places in Netherlands, Belgium and northern Germany 80% obscured. From these locations, maximum partial eclipse occurs at about 9:30 UT.
A total lunar eclipse follows on April 4, 2015 and is visible over Australia, and the Pacific coast of Asia and North America.
NGC 2477 is a stunning open cluster located in the Milky Way rich constellation of Puppis. It's arguably the constellations finest cluster which also contains other superb examples such as M46, M47 and M93. At magnitude +5.8, NGC 2477 is faintly visible to the naked eye but easily seen with binoculars and a fantastic telescope object, especially in medium to large scopes.
The cluster was discovered by French astronomer Nicolas Louis de Lacaille during his tour of South Africa in 1751-52. In total it contains about 300 stars packed into an area 27 arc minutes in diameter with the brightest member star shining at magnitude +9.8. The four-magnitude difference between the combined cluster magnitude and the brightest component is an indication of how rich the cluster is.
NGC 2477 is too far south to have been included in Charles Messier's catalogue, but if he had observed from a more southerly latitude than Paris he almost certainly would have noticed this striking object. Twentieth century America astronomer Robert Burnham described NGC 2477 as "probably the finest of the galactic clusters in Puppis".
The cluster is easily found 2 degrees northwest of zeta Pup (ζ Pup - mag. +2.2) and just northwest of magnitude +4.5 star, b Pup. Located 1.5 degrees west of NGC 2477 and in the same binocular field of view lies large loose open cluster NGC 2451. Another binocular open cluster, NGC 2546, is positioned 4 degrees east of NGC 2477. They are best seen from southern latitudes during the months of December, January and February.
Mercury starts March about halfway through an extended morning visibility period for observers at equatorial and southern latitudes. On February 24th, the fast moving planet reached greatest elongation west and was at highest altitude for this apparition. For example, from latitude 35S (approx. equal to Sydney, Cape Town and Santiago) Mercury was easily visible at magnitude 0.0, hovering 16 degrees above the eastern horizon, 45 minutes before sunrise.
During March, its altitude decreases each subsequent morning but the planet remains visible until lost to the bright twilight glare a few days before months end. However, it should be noted that Mercury doesn't reach maximum brightness (mag -0.7) until the very end of the visibility period, more than 4 weeks after greatest elongation west!
On March 6th, Mercury reaches aphelion - the point in its orbit where it's farthest from the Sun - and is located 0.467 AU (approx. 69.9 million kilometres or 43.4 million miles) from our star. Later in the month on March 17th, the planet passes 1.6 degrees south of much fainter Neptune (mag. +8.0). The difference in brightness between the two planets is about 1,500 times. Two days later, the thin waning crescent Moon passes 5 degrees north of Mercury.
Unfortunately, from northern temperate latitudes the angle of the ecliptic is not favourable and the planet always remains very low down and unsuitably placed for observation throughout the month.
Venus, mag. -4.0, is now a brilliant evening object visible towards the west after sunset. From Northern Hemisphere latitudes the planet sets almost 3 hours after the Sun at the start of the month, increasing to nearly 3.5 hours by months end. The visibility period from southern latitudes is not so favourable but Venus can still be seen for about 1.5 hours. Despite this the planet is unmistakable, a dazzling beacon of light illuminated the early evening skies.
The closest planet-planet conjunction of 2015 occurs on March 4th when Venus at 20 UT passes just 0.1 degrees north of much fainter Uranus (mag. +5.9). Use binoculars or a small scope to spot Uranus, which is 10 magnitudes or 10,000 times fainter than Venus. Also visible five degrees southwest of the pair is Mars (mag. +1.3).
Later in the month on March 22nd, the waxing crescent Moon passes 3 degrees south of Venus making a lovely evening pairing.
Mars continues its direct motion spending most of the month in Pisces although it does make a small cut through one corner of Cetus on March 2nd. The "Red planet" exits Pisces on March 30th, moving into neighbouring Aries.
Throughout March, Mars appears as an inconspicuous early evening object visible above the western horizon as soon as it's dark enough. At the start of the month the planet's located 4 degrees southwest of brilliant Venus. By months end Venus has distanced itself to 17 degrees. To the naked eye, Mars (mag. +1.3) resembles a first magnitude star that sets about 2 hours after the Sun from northern temperate latitudes but only 1 hour for those located further south.
On March 11th, Mars passes just 0.3 degrees north of Uranus with at least binoculars required to spot Uranus. Telescopes at medium to high magnifications reveal the disks of the two planets, Mars at 4.1" across appears slightly larger then Uranus (3.4").
On March 21st, the waxing crescent Moon passes 1 degree south of Mars.
While Venus is the brilliant "star" above the western horizon for a short time after sunset the planet that reigns for the rest of the night is Jupiter. The giant planet is now just one month past opposition and a stunning object moving slowly retrograde amongst the faint stars of Cancer. The current declination of Jupiter slightly favours Northern Hemisphere observers, but even from Southern Hemisphere latitudes where the planet appears lower down, it's unmistakable due to its brightness.
Jupiter is visible towards the east as soon as it's dark enough and remains so until the early hours of the morning. It starts March at magnitude -2.5 with an apparent diameter 45 arc seconds. By months end its slightly fainter and smaller at magnitude -2.3 and 42 arc seconds respectively. Even when viewed through a small telescope a wealth of surface details are visible including cloud bands, twists, knots and storms; including the most famous of all "The Great Red Spot". Also easily visible, but not always at the same time are the four bright Galilean moons: Io, Europa, Ganymede and Callisto.
On March 3rd and 30th, the waxing gibbous Moon passes just over 5 degrees south of Jupiter.
Saturn is located in Scorpius and on March 14th reaches the first of its two stationary points for 2015. This date signals the change in the planets motion from direct to retrograde and is also widely regarded as the beginning of this year's opposition period. By the end of March, Saturn rises before midnight for observers at northern temperate latitudes but nearly 3 hours earlier for those located further south.
As the month progresses the planet brightens slowly from magnitude +0.5 to +0.3 with its apparent size marginally increasing from 17 to 18 arc seconds. Saturn is easy to find in the northern section of Milky Way rich Scorpius. The only nearby star of similar brightness is supergiant star Antares (α Sco mag. +1.0). Visually the two cannot be mistaken, slightly brighter Saturn appears white in colour compared to the stark deep red hue of Antares (a few degrees to the southeast).
Of course the rings of Saturn are its most famous feature and even a small telescope will show them. Through medium and large aperture 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 Titan shines at eight magnitude and can be seen with binoculars. In addition, small size scopes will also show other moons including Rhea, Tethys and Dione.
At the beginning of the month a good opportunity exists to spot bizarre moon Iapetus. This world is famous for its "two-tone" colouration with one side being much darker in colour than the other. As a result, Iapetus when positioned on the western side of Saturn (when viewed from Earth) appears brighter than from the opposite side. On March 3rd, Iapetus reaches greatest western elongation and therefore at it's brightest. At magnitude +10.1, it can be seen with a small scope of 80mm (3.1-inch) aperture.
The 65% illuminated waning gibbous Moon passes 2 degrees north of Saturn on March 12th.
The first half of March offers the last opportunity to view Uranus before it's lost to the bright evening twilight sky. The first planet to be discovered in the telescope age is located in Pisces and starts the month setting about 3 hours after the Sun from northern latitudes but much less from further south. Although technically visible to the naked eye at magnitude +5.9, optical aid will be required to spot Uranus as it battles low down against the twilight sky.
An interesting conjunction occurs on March 4th when brilliant Venus (mag. -3.9) passes just 0.1 degrees north of Uranus. Although 10,000x brighter than Uranus it should be possible to spot the distant planet with a binoculars or a small scope. A second close planetary conjunction occurs a week later on March 11th when Mars passes 0.3 degrees north of Uranus.
Neptune reached solar conjunction on February 26th. The planet is currently located in Aquarius and remains unsuitably placed for observation throughout March from northern temperate latitudes. However, during the second part of the month observers located at tropical and southern latitudes should be able to locate the planet low down above the eastern horizon just before sunrise. At magnitude +8.0, optical aid is recommended to glimpse the planet.
On March 17th, Mercury passes 1.6 degrees south of Neptune. At magnitude -0.3, Mercury is easily visible to the naked eye and over 1,500x brighter than much more distant Neptune. The thin waning crescent Moon passes 4 degrees north of Neptune on March 19th.
As it heads towards the outer depths of the Solar System, comet Lovejoy remains visible with small telescopes and even good binoculars during March. Although now fading and past its best the comet has been a delight over recent months and should remain well within amateur astronomer range for some time to come. For a number of days in late December / early January it even was visible to the naked eye (peak mag. +3.9).
Lovejoy was the fifth comet to be discovered by prolific Australian comet hunter and amateur astronomer Terry Lovejoy. He captured it on August 17, 2014 using nothing more than a 200mm (8-inch) scope with a digital camera attached. The subsequent set of time-lapsed images revealed nothing just a faint point of light (mag. +15) that moved slightly from image to image.
Location and star chart
Comet Lovejoy is now very much a Northern Hemisphere object as it continues to move in the direction of the North Celestial Pole. It spends the end of February in Perseus before crossing into Cassiopeia on the last day of the month. Magnitudes of comets are notoriously difficult to predict but we estimate on March 1st it will shine at +6.0 and therefore at the limit of naked eye visibility but easily seen with binoculars and small telescopes. For those located at southern temperate latitudes the comet is too far north to be seen at all.
From latitudes of at least 35 degrees north Lovejoy never sets during March and is visible all night. It's best seen during the middle two "Moonless" weeks of the month. Highlights include on March 10th when the comet passes 1 degree east of the brightest open cluster in Cassiopeia, NGC 457 the Owl Cluster (mag. +6.4). At magnitude +6.5, Lovejoy is fractionally fainter than the splendid open cluster. A few days later on March 16th it passes 0.1 degrees west of Ruchbah (δ Cas - mag +2.7). As the comet is expected to be more than 4 magnitudes fainter than the star it will probably be difficult to spot against the bright stellar glare. However, it should be easier to see over the next few evenings when it passes just west of two more bright open clusters, M103 (mag. +7.4) and NGC 663 (mag. +7.1). At closest separation Lovejoy is 1 degree from M103 and 3 degrees from NGC 663. It should be noted that Messier Catalogue hunters often mistakenly identify NGC 663 as M103!
The finder charts below show the positions of the comet from January 28th to April 1st, 2015.
NGC 2506 is a magnitude +7.6 rich open cluster located in the constellation of Monoceros. Although its member stars are faint the cluster itself appears quite bright and can be seen with a pair of binoculars. Through telescopes it's an impressive object and of all the Monoceros open clusters is probably the finest. With an age of 1.1 billion years old this is an old cluster. For comparison, M45 (The Pleiades) in Taurus is a youthful 115 million years old with the Hyades cluster 625 million years old. However, NGC 2506 is not nearly as old as the 4 billion years of M67 in Cancer.
William Herschel discovered NGC 2506 on February 23, 1791. Locating the cluster can sometimes be a bit tricky as it's positioned in an area of sky devoid of bright stars. It can be found 5 degrees east-southeast of alpha Mon (α Mon - mag. +3.94) the brightest star in Monoceros. Located 19 degrees southwest of NGC 2506 is the brightest star in the sky, Sirius (α CMa - mag. -1.46). Although α Mon and Sirius are the brightest stars in their respective constellations the difference in apparent brightness between them is enormous; more than 100x.
Large open cluster M48 lies 6 degrees northeast of NGC 2506 with open cluster pair M46 and M47 positioned 6 degrees southwest of NGC 2506. They are best seen during the months of December, January and February.
NGC 40 is a planetary nebula located in the northern constellation of Cepheus. It was discovered by William Herschel on November 25, 1788 who described it as "a 9th magnitude star, surrounded with milky nebulosity". Herschel used his 475mm (18.7) inch telescope to make the discovery but for today's amateur astronomers such a large scope isn't required; it can be glimpsed with just a 100mm (4-inch) instrument. NGC 40 is also known as the Bow Tie nebula, a nickname it shares with another planetary nebula, NGC 2440 in Puppis.
NGC 40 is located just over 17 degrees from the North Celestial Pole and therefore circumpolar from most northern latitudes. It's one of the finest examples of its type in the far northern part of the sky. The best time to look for the nebula is during October, November and December when it appears highest in the sky during early evening. The Bow Tie nebula is also visible from most tropical locations although lower down. However, from southern temperate latitudes it's not visible at all.
Locating NGC 40 can be precarious as it's positioned in a star poor region of eastern Cepheus. One method to find it is by imagining a line connecting Errai (γ Cep - mag. +3.21) and γ Cas (mag. +2.15). The planetary lies approximately one-third of the way along this line.
The Helix Nebula (NGC 7293) is a large and famous planetary nebula located in the faint zodiac constellation of Aquarius. Also known as Caldwell 63 it's one of the nearest objects of its type; a beautiful remnant of a dying star containing a double ring structure not unlike two coils of a spring, hence the popular name "The Helix Nebula".
Although the immediate area surrounding the Helix Nebula is devoid of any particular bright stars, the region can be easily located by star-hoping. NGC 7293 lies roughly halfway along an imaginary line connecting Fomalhaut (α PsA - mag. +1.2) the brightest star in the southerly constellation of Piscis Austrinus and ι Aqr (mag. +4.3). Just over one degree to the east of the Helix Nebula is υ Aqr. At magnitude +5.2 this star is visible to the naked eye under dark skies, simplifying the search for the Helix Nebula.
NGC 2392 is a 9th magnitude bipolar double shell planetary nebula located in the constellation of Gemini. Resembling a person's head surrounded by a parka hood, it's commonly known as the "Eskimo Nebula" or "Clown Face Nebula". William Herschel discovered it from his observatory in Slough on January 17, 1787, describing the planetary nebula as a 9th magnitude star with a bright centre surrounded by equally dispersed nebulosity.
Locating the Eskimo Nebula is relatively easy; it's positioned just east of centre of the bright zodiacal constellation of Gemini, "the Twins" and close to Wasat (δ Gem - mag. +3.5). The easiest way to find Gemini is by identifying its two brightest stars Castor (α Gem - mag. +1.58) and Pollux (β Gem - mag. +1.16). They are positioned east of the familiar "V" shaped asterism of Taurus and to the northeast of the bright prominent constellation of Orion.
Imagine a line extending from Pollux - the brighter of the twins - towards the southwest in the direction of Orions belt. Positioned just over 8 degrees along this line is Wasat and 2.3 degrees southeast of Wasat is NGC 2392. The planetary nebula is positioned next to a mag. +8.2 yellow white star. At first glance through a telescope the pair appears like a wide double star, separated by about 100 arc seconds.
NGC 869 and NGC 884 are two bright open clusters in the constellation of Perseus that are separated by only half a degree of apparent sky. Together, they are commonly known as the "Double Cluster", and form a famous showpiece object that is easily visible to the naked eye and a wonderful sight in binoculars and telescopes. The two clusters are so easy to spot that they have been known since antiquity and probably pre-historically. Greek astronomer Hipparchus first catalogued them around 130 B.C. Early celestial cartographers named them as "h Persei" (NGC 869) and "χ Persei" (NGC 884).
The Double Cluster is located in the far northwest part of Perseus close to the border with Cassiopeia. With a declination of 57N they are circumpolar and therefore never set from most northern latitudes. To locate the Double cluster, draw an imaginary line from Mirfak (α Per - mag +1.8) in a northwest direction towards the centre of the famous "W" of Cassiopeia. The Double Cluster lies just over halfway along this line.
NGC 2775 is a magnitude +10.5 spiral galaxy located in the constellation of Cancer, close to its border with Hydra. The galaxy is unusual in that it contains a very smooth nucleus with multiple spiral arms extending outwards from the central region. What makes the spiral arms interesting is their incredibly complex detail, tightly wound structures and active star formation. Amateur astronomers should also keep their eye on this galaxy; it's been host to 5 supernovae explosions in the past 30 years and you never know when the next one will go off!
To find NGC 2775 look for the head of Hydra "the Sea Serpent". The asterism of stars that forms the head are ω Hyd (mag. +5.0), ζ Hyd (mag. +3.1), ρ Hyd (mag. +4.4), ε Hyd (mag. +3.4), δ Hyd (mag. +4.1), σ Hyd (mag. +4.5) and η Hyd (mag. +4.3). None of the stars are particularly bright but all can be seen with the naked eye. The galaxy is positioned a few degrees east and slightly north of this grouping.
NGC 2775 was discovered by William Herschel in 1783 and is best seen during the months of February, March and April. The galaxy is located 55.5 million light-years from Earth and has an actual diameter of 70,000 light-years. It's estimated to contain 100 billion stars.
IC 2497 is a spiral galaxy located about 650 million light-years distant in the small northern constellation of Leo Minor. Although similar in size to the Milky Way galaxy it appears very small and faint due to its vast distance from us. At apparent magnitude +15.8, the galaxy is beyond the reach of most amateur backyard scopes and seemingly just one of the many thousands of faint galaxies populating the night sky. However a few years ago IC 2497 made international news not because of the galaxy itself but due to a new strangle object that was discovered next to it - Hanny's Voorwerp.
In 2007, Dutch school teacher Hanny van Arkel signed up to the newly created on-line citizen science project Galaxy Zoo. The project enlisted help from the public to classify vast numbers of galaxies based on their physical appearance. The original dataset used was obtained from the Sloan Digital Sky Survey and contained almost 1 million galaxies. With so many galaxies it was thought that the analysis would take years but the organisers were in for a pleasant surprise - within 24 hours the website was receiving almost 70,000 classifications an hour and the site even crashing temporarily due to the intense traffic.
Within a few days of signing up Hanny van Arkel while classifying galaxy IC 2497 noticed a blue object just below the galaxy. She asked if anyone knew what it was, and nobody did! The new object became known as "Hanny's Voorwerp" - Voorwerp the Dutch word for object. It turns out to be a giant gas cloud located next to IC 2497 that's as large as the Milky Way and believed to have been illuminated 100,000 years or so ago by a powerful quasar event at the centre of the galaxy. From recent X-ray and light measurements it appears that the quasar has at sometime within the last 70,000 years either "turned off" or even switched energy states and therefore no longer operating as it was. Whatever has happened, Hanny's Voorwerp and IC 2497 are incredibly interesting objects for professional astronomers.
Location and observing
IC 2497 is located in the western section of Leo Minor and close to the Lynx border. It's positioned 4 degrees directly east of α Lyn (mag. +3.1) and 0.5 degrees southwest of star 13 LMi (mag. +6.1). To spot it at least a 350mm (14-inch) aperture scope is recommended. In total, the galaxy spans just 0.6 x 0.3 arc minutes of apparent size and even with the largest amateur scopes IC 2497 appears small, faint and lacking in detail.
If you think the galaxy is faint, the Voorwerp pushes this to another level. At about magnitude +19, it's incredibly dim! However, a few amateur astronomers with massive Dobsonian reflectors have managed to glimpse it as a ghostly glow hanging off the galaxy. It has been seen with scopes as small as 750mm (30-inch) in aperture!!
Aries "the Ram" is a medium sized northern constellation of the zodiac that lies in a rather barren part of the sky. It contains mostly faint inconspicuous stars and is bordered by Taurus to the east, Perseus and Triangulum to the north, Pisces to west and Cetus to the south. The constellation was one of the original 48 constellations plotted by second century astronomer Ptolemy and today remains as one of the modern 88 constellations defined by the IAU (International Astronomical Union).
In Greek mythology, Aries represents the golden ram that was sent to rescue Phrixos and Helle, the children of King Athamus of Boeotia and his first wife Nephele. The King's second wife, Ino, was resentful and wanted the children, in particular, Phrixos killed. She induced a famine in the Kingdom and then falsified a message to the King indicating Phrixos must be sacrificed in order to save the land. Athamus was about to sacrifice his son when Aries - sent by Nephele - arrived. The ram managed to rescue Phrixos but Helle didn't survive. Phrixus then sacrificed the ram to Zeus with its Golden Fleece presented to King Aeëtes of Colchis. In a later myth, Jason and the Argonauts who actively sought the fleece, eventually managed to steal it. In ancient Egyptian astronomy, Aries was associated with the god Amon-Ra, who was depicted as a man with a ram's head and represented fertility and creativity. The Arabs knew Aries as a sheep and the Chinese as a dog.
The constellation contains a single second magnitude star, a third magnitude star, three fourth magnitude stars and over a dozen fifth magnitude stars. It contains no Messier objects and no bright deep sky objects. However, in its boundaries are numerous faint galaxies within the range of medium/large amateur scopes. For small scopes there are a handful of nice double stars with some bright ones.
Two thousand or so years ago Aries contained the vernal equinox, the point where the Sun annually passes from south to north across the celestial equator. This occurs on or about March 20th and signals the start of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. Due to precession - the slight wobble of the Earth in space - the Vernal Equinox has now moved into neighbouring Pisces.
Aries covers 441 square degrees of sky ranking it 39th in overall size. It's best seen from Northern Hemisphere latitudes during October, November and December. There are several meteor showers that radiate from Aries, including the Daytime Arietids and the Delta Arietids.
Hamal (alpha Ari) – at mag. +2.01 is the brightest star in Aries. It's a K2 orange giant about twice as massive as the Sun that's located 66 light-years distant. The star is variable although the range is extremely small (mag. +1.98 to +2.04). From 2000 BC to 100 BC, Hamal was positioned at the Vernal Equinox.
Sheratan (beta Ari) – is a spectroscopic binary system located 59.6 light-years from Earth. The primary star is a white A5V type main sequence star that completes a highly elliptical orbit with its companion every 107 days. The secondary star is intrinsically fainter and although its spectral type has not been accurately determined it could be F type or even G type similar to the Sun. The stars shine with a combined magnitude of +2.64.
Mesartim (gamma Ari) – is a striking double star consisting of equally bright (mag. +4.5) white-blue components. With a separation of 7.6 arc seconds the two stars are resolvable with any size scope and are widely considered to be one of the prettiest equal pairs. The combined magnitude is +3.9 and the stars lie about 164 light-years away.
Mesartim was one of the first double stars to be telescopically identified. English scientist Robert Hooke accidentally stumbled across it while searching for a comet in 1664.
Epsilon Ari (ε Ari) – is a challenging double of two almost equally bright white stars. Together they shine at magnitude +4.6 but are separated by only 1.4 arc seconds. Telescopes of 100mm (4-inch) should split them but nights of steady transparency are required. A magnification of 200x or so should suffice.
The Epsilon Ari system is located 330 light-years distant. Both stars are classified as A2 V with the primary at magnitude +5.2 and the secondary magnitude +5.6. When first identified as a double by F.G.W. Struve in 1827 the two stars were separated by just 0.5 arc seconds.
Lambda Ari (λ Ari) – mag. +4.8 is located 2 degrees west of Hamal (α Ari). This wide separated double (40 arc seconds) is easily split with small telescopes. The primary star is white (mag. +4.9) and the fainter secondary yellow (mag. +7.7). The pair can be resolved with 7x50 binoculars although the task is much easier with 10x50 models due to increased magnification.
Lambda Ari is located 129 light-years distant.
Pi Ari (π Ari) – is a multiple star system about 800 light years distant. The main star is a magnitude +5.3 blue giant star that's separated by 3.3 arc seconds from its magnitude +8.5 companion. For small telescopes owners this is a challenging split due to the faintness of the secondary and the closeness of the pair. A good quality 100mm (4-inch) refractor on good nights should do the trick but needs to be pushed towards the higher end of its magnification range.
A third fainter star with a separation 25.2 arc seconds (mag. +10.8) is visible in larger scopes. In addition, the primary itself is a spectroscopic binary making this a 4 star system.
30 Ari – a 6th magnitude wide double for small scopes. Both stars are white in colour (mag. +6.5 and +7.0). With a separation of 38 arc seconds they are resolvable with any size scope. The primary component is also a spectroscopic double itself and therefore it's a triple star system.
33 Ari – consists of a primary pure white star of magnitude +5.4 with a magnitude +8.4 companion separated by 24 arc seconds. With a combined magnitude of +5.3, it's just about visible to the naked eye. A small scope 80mm (3.1-inch) scope at about 50x magnification will easily split the pair.
41 Ari – at mag. +3.6 is the brightest star that makes up a small faint naked eye triangle along with 35 Ari (mag. +4.7) and 39 Ari (mag. +4.5). This grouping formed the basis of the short-lived and now obsolete constellation of the "Northern Fly" Musca Borealis. The fly hovered over the back of Aries was finally swatted for good at the beginning of the 20th century when the modern 88 constellations were defined.
A number of faint stars surround 41 Ari making it a multiple star but all except one are due to line of sight effects. The only true companion is separated from the main star by just 0.2 arc seconds and can't be seen visually but can be detected by spectroscopic methods.
The fainter surrounding stars visible through medium sized amateur scopes are of magnitudes +8.8 (sep. 121 arc secs), +10.6 (sep. 27 arc secs) and +11.0 (sep. 33 arc secs).
U Ari – is a Mira type variable star that varies between magnitudes +7.2 and +15.2 over a period of 371 days. At its brightest it's easily visible with 7x50 or 10x50 binoculars. When faintest, a minimum 300mm (14-inch) scope is recommended to spot it.
It's located 1630 light-years distant.
R Ari – is another Mira type variable star that's 4100 light-years away. It varies between magnitudes +7.4 and +13.7 over 187 days. When at its brightest and like U Ari the star is easily visible with 7x50 or 10x50 binoculars.
SX Ari (56 Ari) – is an unusual variable star worth mentioning. It varies in brightness by only 0.1 magnitudes over a period of about a day. What makes this star interesting is it's a rotating helium variable star and the prototype of its class. About 50 such stars have so far been identified.
With an apparent magnitude of +5.8, SX Ari is faintly visible to the naked eye but the brightness variations are far too small to be noticed visually.
NGC 772 – is the largest and brightest of the galaxies in Aries. It's a magnitude +10.3 type SA(s)b unbarred spiral galaxy visible in small scopes and in total spans 7.2 x 4.3 arc minutes of apparent sky. Located 105 million light-years from us, NGC 772 is an extremely large galaxy with an actual diameter of 220,000 light-years. For comparison this is twice the size of our Milky Way and 1.5 times the size of the Andromeda Galaxy (M31) the largest Local Group galaxy. NGC 772 is estimated to contain at least 1 trillion stars.
Locating NGC 772 is quite easy. The galaxy is positioned 2 degrees east-southeast of Mesartim (γ Ari) and forms a small right-angle triangle with Mesartim and Sheratan (β Ari). A 100mm (4-inch) telescope at low powers reveals a faint oval misty patch of light spread over 3 arc minutes. On nights of good seeing the nucleus appears well defined and surrounded by a hazy nebulosity representing the spiral arms. It's possible to glimpse the spiral arms using a 200mm (8-inch) scope but they are much easier to see in larger backyard scopes of 300mm (12-inch) aperture or more.
As a result of gravitational tidal forces probably from nearby satellite galaxy NGC 770 one of the spiral arms in NGC 772 is more developed that the others. It appears longer and slightly elongated in shape and as a result Halton Arp included NGC 772 in his Atlas of Peculiar Galaxies as Arp 78.
To date, two supernovae SN 2003hl and SN 2003iq have been observed in NGC 772.
NGC 770 – observers with very large backyard scopes maybe able to spot NGC 770 in the same field of view as NGC 772. This is the largest satellite galaxy of NGC 772 but its small and faint, shining at a feeble magnitude +14.1 and spanning only 1.1 x 0.8 arc minutes. A 400mm (16-inch) scope reveals an object that looks like an out of focus star. At high magnifications it’s possible to notice a small amount of detail such as the nucleus.
NGC 821 – is a mag. +10.8 type E6 elliptical galaxy located in the far southern section of Aries close to the border with Cetus and Pisces. It's positioned 2.5 degrees north of star ξ1 Cet (mag. +4.3) and can be spotted with 100mm (4-inch) scopes appearing as a small faint round nebulous patch of light. NGC 821 has an apparent size of 2.5 x 1.7 arc minutes. When viewed with larger backyard scopes the surface appears uneven in brightness with some mottling visible.
The galaxy is 80 million light-years distant with an actual diameter of 60,000 light-years.
NGC 972 – is an inclined spiral galaxy at the northern section of the constellation. It's positioned 3.5 degrees northwest of double star 41 Ari (mag. +3.6). Located just off an imaginary line connecting NGC 972 and 41 Ari is star 35 Ari (mag. +4.7).
At magnitude +11.4, NGC 972 is best seen with at least a medium sized scope. Through a 200mm (8-inch) instrument it appears as an elongated misty envelope of nebulosity with a brighter centre just north of a faint double star. The galaxy covers 3.3 x 1.7 arc minutes but has a reasonably high surface brightness.
NGC 1156 – is another galaxy located near to star 41 Ari but this time in the opposite direction to NGC 972. It's an irregular object positioned 3 degrees southeast of the star. At magnitude +11.7 you would probably not expect much from NGC 1156 but be in for a pleasant surprise. Even small scopes show some details including a faint ghostly like halo surrounding a brighter core with a number of foreground stars also visible in the same field of view. On nights of good seeing, a 200mm (8-inch) scope reveals mottling with larger instruments displaying subtle texture in the halo.
NGC 877 – mag. +11.8 is a spiral galaxy 1.5 degrees southeast of 19 Ari (mag. +5.7). There are two 8th magnitude stars adjacent to NGC 877 and the galaxy appears in the same low power field of view as one of the stars. A 200mm (8-inch) scope shows little detail except for a slightly brighter core. Increasing the aperture does not significantly enhance the view although the galaxy appears larger and hints at structural details. It's located 180 million light-years distant.
NGC 678 and NGC 680 – are a pair of 12th magnitude galaxies very close together in the eastern part of the constellation close to the Pisces border. They are separated by only 5 arc minutes of apparent sky, which corresponds physically to about 200,000 light-years. NGC 678 and 680 are currently interacting with each other resulting in shape distortions. They are part of the NGC 691 group of galaxies and are both located 125 million light-years away.
Of the two, NGC 680 is an elliptical galaxy and the brighter at magnitude +11.9. It measures 1.8 x 1.6 arc minutes. Although larger in both apparent and absolute size, NGC 678 is not as bright as NGC 680. This spiral galaxy shines at magnitude +12.5 with an apparent size of 4.5 x 0.8 arc minutes. It appears almost edge on from our perspective.
Both galaxies are visible in medium sized telescopes but are fairly faint. What's noticeable are the different shapes; NGC 680 is essential round, NGC 678 needle like. A prominent dust lane bisects through NGC 678 and can be seen in larger amateur scopes.
NGC 697 – is a barred spiral galaxy with an apparent magnitude of +12.0 that's located 2 degrees northwest of Sharatan (β Ari). A 200mm (8-inch) scope reveals a highly inclined thin elongated patch of light. It stands out quite well due to a reasonably high surface brightness. There is a 12th magnitude star positioned at the eastern edge of NGC 697.
The galaxy NGC 674 is widely believed to be a mistake entry in the NGC catalogue and though to be the same object as NGC 697.
Mercury reached inferior conjunction on January 30th and consequently was too close to the Sun to be observable. However, since the planet moves fast it takes less than two weeks before it reappears as a morning object for observers at tropical and Southern Hemisphere latitudes. Mercury then climbs higher in the sky each subsequent morning until peaking on February 24th, when it reaches greatest elongation west (26.7 degrees from the Sun). From northern temperate latitudes, the angle of the ecliptic is not favourable and during this time the planet is unsuitably placed for observation.
As often is the case with Mercury apparitions, one hemisphere of the Earth is favoured over the other. On this occasion it's the Southern Hemisphere with the added bonus that this also happens to be the most favourable morning apparition of the year. With an extended period of visibility the opportunity to spot the illusive planet over the next few weeks is superb.
For example, from latitude 35S (approx. equal to Sydney, Cape Town and Santiago) Mercury (mag. +0.3) will appear 13 degrees above the eastern horizon 45 minutes before sunrise on February 14th. The planets altitude continues to improve slightly each subsequent morning until February 24th when it peaks at 16 degrees above the horizon. Mercury shines at mag. 0.0 on this day.
The diagram below shows the February and March apparition of Mercury from latitude 35S. The thin waning crescent Moon passes 3.5 degrees north of Mercury on February 17th.
From northern temperate latitudes, Venus is a brilliant evening object visible above the west-southwestern horizon after sunset. At the start of the month the planet sets over 2 hours after the Sun from such latitudes increasing to over 3 hours by months end. Even though it's currently languishing towards the lower end of its brightness scale (mag. -3.9) Venus is always brighter than any other planet.
During September the phase of Venus decreases from 92% to 87% with the apparent diameter increasing marginally from 11 to 12 arc seconds. From the Southern Hemisphere, Venus appears low down above the western horizon and sets just over 1 hour after the Sun.
On February 21st, Venus passes less than 0.5 degrees south of Mars. At magnitude +1.3 the "Red planet" is over one hundred times fainter than brilliant Venus! The waxing crescent Moon is nearby on the same day making a lovely grouping in the early evening sky.
Mars remains an early evening object towards the west during February. The fourth planet from the Sun continues its rapid direct eastward motion against the background stars. It starts the month in Aquarius before crossing into Pisces on February 11th where it remains for the rest of the month. At magnitude +1.2, Mars is not that bright and there are currently 17 night-time stars brighter! Mars will be very close to Venus on the evening of February 21st with the Moon also nearby.
By months end, Mars sets 2.5 hours after the Sun from northern temperate latitudes but only 1 hour for those located further south.
Jupiter reaches opposition on February 6th and therefore visible all night. On this day, the giant planet rises in the east when the Sun sets in the west and then sets in the west as the Sun rises again for the new day. At magnitude -2.6, Jupiter is far brighter than any night-time star and unmistakable due to its brilliance.
This year at opposition, Jupiter is located 4.346 AU (650.18 million kilometers or 404.01 million miles) from Earth, which gives it an apparent size of 45 arc seconds. The planet is currently moving retrograde and spends the first few days of the month in Leo before crossing the constellation boundary into Cancer on February 4th. Jupiter's current declination of +16 degrees favours Northern Hemisphere based observers with the planet appearing higher in the night sky and visible for a longer period of time.
To the naked eye Jupiter appears creamy or off-white in colour. Unlike the brightest stars it doesn't twinkle at all. Compare the planet (or any other bright planet) with Sirius (α CMa - mag. -1.45) the brightest star in the night sky. Sirius twinkles and flashes many different colours particularly when close to the horizon but Jupiter doesn't twinkle at all.
A pair of 7x50 or 10x50 binoculars will reveal the planets disk although it's small. Also visible are Io, Europa, Ganymede and Callisto, the four large Galilean moons. As they orbit Jupiter they constantly change position; sometimes all four are visible but often some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.
When viewed through a telescope, Jupiter is an awesome sight. A 80mm (3.1 inch) scope shows the main northern and southern equatorial cloud belts and finer details along with the Galilean moons. Larger telescopes reveal much more detail including smaller belts, ovals, festoons, darkenings and of course the famous "Red Spot".
On February 4th, the full Moon passes 5 degrees south of Jupiter.
Saturn is now a morning object moving direct in northern section of Scorpius "the Scorpion". The planet is located a few degrees northwest of Antares (α Sco mag. +1.0) the brightest star in the constellation. Saturn is currently far better seen from the southern latitudes where by months end it rises well before midnight. From northern temperate locations Saturn rises around 1:30am at the end of February.
Saturn brightens from mag. +0.6 to +0.5 as the month progresses with its apparent size increasing marginally from 16 to 17 arc seconds. On February 13th, the last quarter Moon passes 2 degrees north of the planet.
Uranus, mag. +5.9, remains an early evening object during February. The distant ice giant is visible towards the west as soon as it's dark enough. The planet is easily visible with binoculars but by months end sets less than 3 hours after the Sun.
Uranus is currently located in Pisces close to the Cetus border and about 20 degrees southeast of the Great Square of Pegasus. At the end of the February, Venus (mag. - 3.9) and Mars (mag. +1.3) are less than 10 degrees southwest of the much fainter Uranus.
On February 21st, the waxing crescent Moon passes 0.3 degrees north of Uranus and an occultation is visible from southeast Canada and northeast America at 22:16 UT.
Neptune reaches solar conjunction on February 26th and therefore is not visible this month.
The brightest comet that can be seen in the night sky at the moment is comet Lovejoy (C/2014 Q2). At the end of December it was a superb binocular/telescope sight, faintly visible to naked eye as it moved through the southern constellations of Columba and Lepus. The comet then continued to brighten until peaking at magnitude +3.9 during closest approach to the Earth on January 7th. On this day it was 0.469 AU (70.2 million km or 43.6 million miles) distant from our planet and although the bright Moon somewhat interfered, the comet was easily visible with binoculars and small scopes as a large hazy circular patch of light. When imaged or photographed it displayed a long thin wispy green tail that extended over 10 degrees in length.
Now fading Lovejoy remains excellently placed for observation from the Northern Hemisphere during February. As the month progresses it's expected to fade from magnitude +4.8 to +6.3. For the first part of February the comet should still be visible to the naked eye and will remain an easy binocular and small telescope target for quite sometime to come.
From southern latitudes the comet maybe glimpsed low down above the northern horizon at the start of February. However, for these observers it isn't long before it disappears from view completely. On January 30, Lovejoy reaches perihelion (closest point to the Sun) at 1.2908 AU equivalent to 193.1 million kilometres or 120 million miles.
Location and star chart
During February, Lovejoy continues its northwesterly motion against the background stars. The comet starts the month in southeastern Andromeda close to the border with Triangulum and Perseus. On February 1st it's located 4 degrees southeast of star Almach (γ And - mag. +2.1) and is expected to shine at magnitude +4.8. Over the next few nights the comet moves closer to Almach and on February 5th the two objects are separated by only 0.5 degrees.
Although Lovejoy is now moving away from the Earth and heading into deep space it still moves reasonably quickly against the night sky backdrop. It's possible to notice its motion from one night to the next and even in a single observing session. On February 20th/21st the comet passes less than half a degree west of M76, the Little Dumbbell nebula in Perseus. At magnitude +10.1 and spanning 2.7 x 1.8 arc minutes this planetary nebula is one of the faintest, smallest and difficult objects in Messier's catalogue.
February offers an excellent opportunity for northern-based observers to follow comet Lovejoy. It based high in the sky and should be visible through binoculars or small scopes as a fading fuzzy nebulous patch of light that may even appear slightly greenish with a small tail.
The finder charts below show the positions of the comet from January 18th to March 1, 2015.
Jupiter the Solar System's largest planet has been well placed for observation for a few months now as it moves retrograde amongst the stars of Leo. Since the end of last year the planet was visible in early evening, appearing as a spectacular dazzling object. On February 6th, Jupiter is at its best for 2015 when the giant planet reaches opposition. On this day, it will rise in the east as the Sun sets and then set in west as the Sun re-rises on the opposite side of the sky. With a magnitude of -2.6, the "King of the planets" is unmistakable and far brighter than any nighttime star.
Jupiter stars the month in western Leo before crossing the constellation boundary into Cancer on February 4th where it remains for the rest of the month. Positioned 12 degrees southeast of Jupiter is Regulus (α Leo - mag. +1.4) the brightest star in Leo with the Gemini twin stars of Castor (α Gem - mag. +1.6) and Pollux (β Gem - mag. +1.2) located 25 degrees northwest of Jupiter. Although all three stars are bright, Jupiter far outshines them being about 35x brighter than Pollux and 40x brighter than Castor and Regulus.
The current northern declination of Jupiter slightly favours Northern Hemisphere observers, but even from southern latitudes where the planet appears lower down it's still unmistakable due to its brightness.
At opposition, Jupiter is located 4.346 AU (650.18 million kilometers or 404.01 million miles) from Earth. Although Jupiter is slightly further from Earth than during the last few oppositions its apparent size is still an impressive 45.4 arc seconds. Of all other planets only Venus - on rare occasions - displays a greater apparent size than Jupiter. At very favourable oppositions, when Jupiter is closest to Earth, it can reach magnitude -2.9 with an apparent size of over 50 arc seconds.
Popular 7x50 and 10x50 binoculars will reveal the disk of Jupiter. It appears off white or creamy coloured but no surface details are visible. Also visible are the four large Galilean moons (Io, Europa, Ganymede and Callisto). The moons continuously change position as they orbit Jupiter and sometimes all four are visible, but on other occasions some or all of the satellites will be temporarily obstructed and hidden as they pass behind or in front of Jupiter's disk.