At the beginning of October observers at southern latitudes should be able to catch Mercury low down towards the western horizon just after sunset. However, it won't be long before the planet is lost to the bright twilight glare as it draws in towards the Sun. Mercury then passes through inferior conjunction on October 16th. The planet is such a fast mover that observers at equatorial and northern temperate latitudes will be able to spot this elusive world low down towards the east just before sunrise during the last week of October. From southern temperate latitudes, Mercury is unsuitably placed for observation during this time.
The planet increases in brightness from mag. +0.8 on October 25th to -0.5 at the end of the month.
Venus is currently located on the opposite side of the Sun and passes through superior conjunction on October 25th. As a result the planet is not suitably placed for observation during October.
Mars remains an evening object during October but the "Red planet" has now faded to mag. +0.9, down from a peak of -1.5 during opposition last April. On September 27th, the planet passed 3 degrees north of its "rival", red supergiant Antares (α Sco - mag. +1.0) the brightest star in Scorpius. At magnitude +0.8, Mars was fractionally the brighter but otherwise to the naked eye they appeared similar. The planet is now "speeding" away from Antares as it continues its direct motion through Ophiuchus before moving into Sagittarius on October 21st.
From northern temperate latitudes Mars sets about 2.5 hours after the Sun. From locations further south, planet watchers can follow the planet for about 4 hours before it disappears.
On October 26th, Mars reaches its most southerly point at approx. 25 degrees south. A few days later the waxing crescent Moon passes 7 degrees north of Mars (Oct 28th).
Jupiter is a now brilliant object that dominates the morning sky. From northern temperate latitudes the planet rises 4 hours before the Sun at the start of October improving to around midnight by months end. For those located further south the period of visibility is not quite as good, but only about a couple of hours less.
The great planet starts October in Cancer at magnitude -1.9 with an apparent size of 34 arc seconds. Moving direct it then crosses the constellation boundary into Leo on October 14th where it remains for the remainder of the month. At months end, Jupiter shines at magnitude -2.1 with an apparent size of 36 arc seconds.
Even when viewed through a small telescope a wealth of surface details are visible on Jupiter. These include cloud bands, twists, knots and storms; the most famous of all being "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 October 18th, the waning crescent Moon passes 5 degrees south of Jupiter.
Saturn, mag. +0.6, is visible towards the southwest sky as soon as it's dark enough. The planet is currently moving direct in Libra. It's better seen from southern latitudes where it sets some 3 hours after the Sun at the start of the month, decreasing to an hour by the end of October. From northern locations the visibility period is shorter and by months end Saturn will be lost to the Sun's glare.
On October 4th, dwarf planet Ceres (mag. +9.0) passes 0.4 degrees north of Saturn. The thin waxing crescent Moon passes a degree north of the planet with an occultation visible from the northern Atlantic on October 25th.
Uranus shines at its best this month; it reaches opposition in Pisces on October 7th. The seventh planet from the Sun has a magnitude of +5.7 and therefore is just about visible to the naked eye. However, dark moonless skies are required along with good seeing conditions in order to spot the distant ice giant. For those without such fortunate seeing conditions, the planet is an easy binocular catch.
Uranus was discovered by Sir William Herschel on March 13, 1781 from the garden of his house at 19 New King Street, Bath, England. At opposition this year, the planet will be located approx. 19.041 AU or 2844.5 million km (1767.5 million miles) from the Earth, which results in an apparent diameter of 3.7 arc seconds. A small telescope at high magnification will show the planet as an obviously non-stellar small green disk. However, even when viewed through the largest amateur telescopes it's difficult to make out any details on the surface of Uranus.
An extremely rare event occurs on October 8th when the full Moon in total eclipse occults Uranus. Unfortunately, its unlikely many people will be able to observe this conjunction as it occurs during daytime and is only visible from remote Greenland.
Neptune, mag. +7.8, continues to move very slowly retrograde in Aquarius during October. Although now passed opposition the planet remains well placed for observation this month, visible as soon as it's dark enough until after midnight.
Neptune is far too faint to be seen with the naked eye but it's relatively easy to spot with binoculars once the correct region of sky has been identified. On October 5th, the waxing gibbous Moon passes 5 degrees north of Neptune.
M87 is a supergiant elliptical galaxy that's a prominent member of the Virgo cluster of galaxies. It's one of the largest and most luminous galaxies known and a strong source of radiation, particularly radio and X-ray emissions. At the centre of M87 is a supermassive black hole with a jet of extremely energetic plasma extending outwards for at least 5000 light-years. The galaxy is therefore an interesting object for both professional and amateur astronomers alike.
With an apparent magnitude of +8.6, M87 is the second brightest of the Virgo cluster galaxies; only M49 at mag. +8.4 is brighter. On dark moonless nights it's visible with 7x50 or 10x50 binoculars, appearing as a faint hazy patch of light. The galaxy was one of eight discovered by Charles Messier on March 18, 1781. On this day he also re-discovered fine globular cluster M92.
M87 lies at the heart of the Virgo cluster. It can be found by imagining a line connecting Denebola (β Leo - mag. +2.1) with Vindemiatrix (ε Vir - mag. +2.8). Just over half way along this line is M87. Faint elliptical galaxy M89 is positioned just over a degree east of M87 with galaxy pair M84/M86 located 1.5 degrees northwest of M87.
The Virgo galaxies are best seen during the months of March, April and May.
M88, mag. +9.6, is a fine spiral galaxy located in Coma Berenices that's a member of the Virgo cluster of galaxies. It has a reasonably high surface brightness - partly due to its favourable inclination of 30 degrees - and therefore a nice small telescope object. It appears somewhat like a much smaller and fainter version of M31, the spectacular Andromeda Galaxy.
M88 is one of the brightest Seyfert galaxies in the sky. These types of galaxies exhibit extremely active quasar like nuclei and are strong emitters of electromagnetic radiation with highly ionised spectral emission lines present. They are named after 20th century American astronomer Carl Seyfert who first identified them. Galaxies M51, M66, M77, M81, M87 and M106 also belong to this class of object.
M88 was one of the eight Virgo cluster galaxies discovered by Messier on his most productive night, March 18, 1781. Messier's description of M88 was of a "nebula without star between two small stars and one star of the sixth magnitude, which appear at the same time as the nebula in the field of the telescope". He also remarked that it was similar in appearance to M58. William Parsons the 3rd Earl of Rosse was the first to recognise the spiral shape and listed M88 as one of 14 "spiral nebulae" discovered to 1850.
As with some of the Virgo galaxies, locating M88 can be challenging since there are no bright stars located in the vicinity. The galaxy is positioned about a degree north of the Coma Berenices-Virgo constellation boundary with the general area of sky located midway between stars Denebola (β Leo - mag. +2.1) and Vindemiatrix (ε Vir - mag. +2.8). Tenth magnitude barred spiral galaxy M91 is located just east of M88.
The best time of year to look for the Virgo galaxies is during the months of March, April and May.
M89 is another member of the Virgo Cluster of galaxies. It's a small magnitude +10.0 elliptical galaxy (type - E0) discovered by Charles Messier on March 18, 1781. On this bumper night for Messier he also discovered seven other Virgo galaxies and re-discovered globular cluster M92 in Hercules. Recent observations indicate that M89 may be nearly perfectly spherical in shape. This is unusual because all other known ellipticals are elongated. However, it's possible that the spherical nature of M89 is purely a visual affect resulting from its orientation from our perspective.
The galaxy is not as bright as some other group members and therefore a challenging small telescope object. Messier's original discovery observation acknowledges this: "extremely faint and pale and it's not without difficulty that one can distinguish it". The galaxy is best seen with large telescopes but generally featureless and rather unexciting through most amateur instruments.
M89 is located in Virgo just south of the Virgo-Coma Berenices constellation boundary. It's positioned roughly 60% along an imaginary line connecting stars, Denebola (β Leo - mag. +2.1) and Vindemiatrix (ε Vir - mag. +2.8). Slightly brighter spiral galaxy M90 is 0.75 degrees northeast of M89. One degree southeast of M89 is fine barred spiral galaxy M58 with supergiant elliptical galaxy M87 located about a degree west of M89.
The Virgo galaxies are best seen during the months of March, April and May.
M100, mag. +9.5, is a spiral galaxy located in the southern part of constellation of Coma Berenices. It's one of the brightest members of the Virgo cluster of galaxies appearing almost face-on from our perspective. M100 exhibits prominent well-defined spiral arms and is therefore regarded as an example of a grand design spiral galaxy; other notable galaxies that fall into this category are M51, M74, M81 and M101.
M100 was discovered - along with M98 and M99 - by Pierre Méchain on March 15, 1781. Charles Messier subsequently observed all three objects and added them to his catalogue on April 13, 1781. He described the galaxy as faint without stars. It was not until 1850 that the spiral nature of M100 was first detected. Ango-Irish astronomer William Parsons the 3rd Earl of Rosse was the person to achieve this. He included M100 in a list of 14 spiral nebulae he had observed.
Finding the area of sky where M100 is positioned is not so difficult once one is familiar with the location of Virgo cluster. The centre of the cluster is located close to supergiant elliptical galaxy M87, about halfway along a line connecting Denebola (β Leo - mag. +2.1) with Vindemiatrix (ε Vir - mag. +2.8). M100 is positioned towards the northern section of the group, 2 degrees southeast of star 11 Com (mag. +4.7).
The Virgo cluster galaxies are best seen during the months of March, April and May.
Comet Jacques is now past its best but remains well placed for observation high in the sky during the second half of September. In July when at its brightest, Jacques reached the cusp of naked eye visibility; just too faint to be seen without optical aid but nevertheless a superb sight in binoculars, telescopes and a wonderful object for astro imagers.
Location and star chart
The comet is currently traveling in a south-westerly direction. It started September by moving into Cygnus from Cepheus where it remains until the middle of the month. During this period it traveled almost parallel to the body of the "Swan" and on September 14th passes a degree east of beautiful double star Albireo (β Cyg - mag. +3.0). Later on the same day Jacques moves into Vulpecula and on September 21st passes just west of the large open cluster Collinder 399; more commonly know as the "Coathanger". This loose star grouping is easily visible in binoculars and does look remarkably like a Coathanger! Jacques then crosses into Sagitta and onto Aquila (Sep 24th), where it stays for the remainder of the month.
The comet is expected to dim from magnitude +7.6 to +9.9 as the month progresses. During the second part of the month, it's visible relatively high in the sky after sunset from most locations as soon as it's dark enough. It should be visible with small telescopes during this time, although it will start to become more and more difficult to spot with binoculars as it dims. It may also be difficult to see against the rich Milky Way background that fills this part of the sky.
The finder chart below shows the positions of Jacques from September 10th to September 23rd, 2014.
M90 is a spiral galaxy located in Virgo. It's a member of the Virgo Cluster and one of the largest and brightest spirals in the group. With an apparent magnitude of +9.6, M90 is visible through small scopes as a reasonably bright oval shaped patch of light. It appears bright in medium size telescopes but to spot the spiral structure requires a larger amateur scope.
The galaxy was one of eight galaxies, all Virgo members, discovered by Charles Messier on March 18, 1781. It's located about 60 Million light-years distant and is intrinsically large with an actual diameter of 165,000 light-years, more than the Andromeda Galaxy (M31). It's estimated to contain a trillion stars.
M90 is positioned close to the centre of the Virgo cluster and right at the Virgo-Coma Berenices constellation boundary. The centre of the cluster is located roughly halfway along a line connecting stars, Denebola (β Leo - mag. +2.1) and Vindemiatrix (ε Vir - mag. +2.8). In the same area of sky are M84, M86 and M87 with M90 positioned 1.5 degrees northeast of M87. The small elliptical galaxy M89 is 0.75 degrees southwest of M90 with M91 about a degree to the north-northwest of M90. Tenth magnitude spiral galaxy M88 is located 1.5 degrees northwest of M90.
The Virgo galaxies are best seen during the months of March, April and May.
Comet Oukaimeden, which was discovered at the end of last year, has recently brightened sufficiently to move within binocular and small telescope range. During September, the comet should continue to improve until peaking at about magnitude +6.0 on the 19th, just short of naked eye visibility. It can be seen from the tropics and southern locations.
At the beginning of the month, Oukaimeden appeared as a well-placed morning object high in the sky towards the east before sunrise from the tropics and Southern Hemisphere. As the month progresses, it draws in towards the Sun but still remains well placed for at least the first two weeks of the month before switching to the evening sky. It should then be visible low down above the western horizon just after sunset during the last week of September.
From mid-latitude northern latitudes, Oukaimeden is not suitably placed for observation. It was visible for the first few days of September, low down towards the eastern sky during morning twilight, but then quickly lost to the Sun's glare.
Oukaimeden was discovered on November 12, 2013 at Oukaimeden observatory in Marrakech, Morocco using a 0.5-metre (20-inch) reflecting telescope by Michel Ory. It was the fourth comet discovered at the observatory and the first by Michel Ory. At apparent magnitude +19.4, Oukaimeden was extremely faint when found.
Location and star chart
Oukaimeden started September at magnitude +8.4 in Monoceros, heading in a southeasterly direction against the "fixed" background stars. It was faintly visible with 7x50 or 10x50 binoculars but much easier with telescopes, appearing as a smaller and fainter version of another current comet, Jacques (C/2014 E2). Oukaimeden then moved into Puppis on September 7th where it remains for 3 days. The next stop on its journey is Hydra, the largest of all modern 88 constellations. The comet stays in Hydra until September 22nd, apart from a short diversion of less than 24 hours into Antlia on September 16th. From September 22nd to 27th it moves through Centaurus before returning back to Hydra, where it remains for the rest of the month.
On 16 September 2014, Oukaimeden will pass 0.480 AU (71.8 million kilometres or 44.6 million miles) from the Earth and will reach perihelion on September 28th when it's 0.625 AU (93.5 million kilometres or 58.1 million miles) distant from the Sun.
The finder chart below shoes the positions of Oukaimeden from September 8th to 15th, 2014.
M104 more commonly known as the Sombrero Galaxy is a spectacular, almost edge-on, spiral galaxy located in Virgo. At magnitude +8.4, the Sombrero appears in binoculars as a small patch of nebulosity. Its most striking feature - visible in medium/large sized amateur scopes - is a ring of thick dust that encapsulates the bulge of the galaxy, giving the appearance of a Sombrero hat. Many astronomers regard M104 as the finest of all galaxies in Virgo.
Pierre Méchain discovered M104 on May 11, 1781. A couple of years later he described the galaxy in a letter to Johann Bernoulli and subsequently it was published in the Berliner Astronomisches Jahrbuch (Berlin Astronomy Year Book). Charles Messier made hand-written notes about this and five other objects but none were included in the final published catalogue version. The Sombrero Galaxy was finally added to the "official" catalogue in 1921 with the other five "missing" items (M105 to M109) added a few years later.
M104 was one of the first galaxies to have its spectra and velocity measured by Vesto Slipher in 1912. He noted that the object was redshifted and therefore receding from us, the current accepted rate being 900 km/s. Slipher's redshift calculation of M104 along with similar observations from other galaxies pointed towards an expanding Universe, hence providing a key piece of evidence for the Big Bang Theory.
The Sombrero Galaxy is located very close to the constellation boundary between Virgo and Corvus. It's positioned 11.5 degrees directly west of Spica (α Vir - mag. +1.0) and 6 degrees northeast of delta Crv (δ Crv - mag. +2.9). The stars chi Vir (χ Vir - mag. +4.7), psi Vir (ψ Vir - mag. +4.8) and 21 Vir (mag. +5.5) form a faint naked-eye triangle just north of M104.
It's best seen during the months of March, April and May.
M91, mag. +10.3, is a barred spiral galaxy located in the southern part of constellation Coma Berenices. It's a member of the Virgo cluster of galaxies and was discovered by Charles Messier on March 18, 1781. This was a productive night for Messier; he discovered eight objects, all of them Virgo cluster galaxies and also rediscovered globular cluster M92 in Hercules. When recording the position of M91, Messier incorrectly referenced its location from galaxy M58 when he meant to use M89. It was only a one degree mistake, however the result meant that M91 was a missing object for almost 200 years!
It was not until 1969 when some astronomy detective work by William Williams solved the mystery of M91. In 1969, he pinpointed the location in the sky after applying Messier's measurements to a starting point of M89 and concluded that the missing object was almost certainly NGC 4548.
Finding M91 can be challenging. The galaxy is located about a degree north of the Coma Berenices-Virgo constellation boundary but there are no bright stars in the vicinity. The general area of sky can be found by imagining a line connecting Denebola (β Leo - mag. +2.1) with Vindemiatrix (ε Vir - mag. +2.8). About 60% of the way along this line is elliptical galaxy M89 (mag. +10.0) with M91 positioned two degrees directly north of it.
M91 and the Virgo cluster galaxies are best seen during the months of March, April and May.
Although just beyond naked eye visibility, comet Jacques has recently put on a fine display for binocular and telescope observers. During August the comet was high in the sky from northern locations - even circumpolar in many cases - as it passed through the constellations of Auriga, Perseus, Camelopardalis, Cassiopeia and Cepheus.
With 7x50 or 10x50 binoculars Jacques appeared as an out of focus "fuzzy" ball of light. Small telescopes of the order of 80mm (3.1-inch) aperture showed a bright centre, diffuse coma with hints of a short thin tail that was better seen through larger instruments. Photographically the comet appeared green in colour with a bright coma and narrow tail extending many degrees.
Now fading, Jacques remains high in the sky from northern and tropical locations throughout September. From the Southern Hemisphere, it reappears low down in the northern part of the sky at the beginning of the month with the visibility improving each day.
The comet remains visible with telescopes during September, although binocular observers may struggle to spot it towards the end of the month. It's expected to fade from magnitude +7.6 to +9.9 during this time. However, comets are unpredictable objects and almost anything can happen, so keep watching!
Location and star chart
After recently passing north of the "W" of Cassiopeia and to within a degree of the Garnet star in Cepheus, Jacques moved in Cygnus on September 2nd. The comet is now heading south-westerly and on September 5th will be located 2.5 degrees west/northwest of the brightest star in the constellation, Deneb (α Cyg - mag. +1.25) which also forms one corner of the "Summer Triangle" asterism. Jacques then continues its path through the rich Milky Way star fields of Cygnus before moving into Vulpecula on February 14th, Sagitta on September 21st and Aquila on September 24th, where it stays for the remainder of the month.
The finder chart below shows the positions of Jacques from September 1 to September 9, 2014.
Mercury reaches greatest elongation east on September 21st when it's positioned 26 degrees east of the Sun, close to the maximum possible obtainable. Unfortunately due to the angle of the ecliptic, the planet is unsuitably placed for observation from northern temperate latitudes this month. However for observers in equatorial and more southerly locations Mercury is superbly placed, visible above the western horizon just after sunset throughout September and into early October. From these latitudes, this also happens to be the most favourable evening apparition of the year.
For example, on September 1st from latitude 35S (approx. equal to Sydney, Cape Town and Santiago), Mercury will appear 10 degrees above the western horizon 45 minutes after sunset. The planets altitude then increases each subsequent evening, peaking on the day of greatest elongation east at 17 degrees. By months end Mercury is still 14 degrees above the horizon. The diagram below shows the changes in position of Mercury, 45 minutes after sunset from latitudes of 35 degrees south.
During September, the brightness of Mercury fades slightly from magnitude -0.2 to +0.3. On the 21st, the planet passes 0.6 degrees south of Spica (α Vir - mag. +1.0) with the thin waxing crescent Moon 4 degrees south of Mercury on the same day, forming a nice triangle.
Venus long morning apparition finally comes to an end during September. At the start of the month the planet remains a brilliant object low above the eastern horizon before dawn, shining at magnitude -3.9. However, it's not long before the brightest planet of all is lost to the glare of the Sun. For those at southern latitudes the planet will only be visible for the first week of the month, observers at northern temperate latitudes should be able to catch Venus until at least the middle of the month with those in the tropics possibly able to glimpse the planet for a few more days still.
On September 5th, Venus reaches perihelion at a distant of 0.718 AU (approx. 107 million kilometres or 66.7 million miles) from the Sun. On the same day the planet passes 0.8 degrees north of the Regulus (α Leo - mag +1.4), the brightest star in Leo.
Mars remains an evening object during September, visible after sunset above the southwestern horizon (NH) / western horizon (SH). The Earth is currently distancing itself from the planet so it continues to fade in brightness (mag. +0.6 to +0.8) and shrink in apparent size (6.8 to 6.1 arc seconds) as the month progresses.
Having overtaken Saturn at the end of last month, the "Red planet" starts September in Libra. It then continues its rapid direct movement against the "fixed" background stars, passing into Scorpius on September 13th before moving into Ophiuchus on September 26th, where it remains for the remainder of the month.
Last month it was interesting to compare the colours of deep orange-red Mars as it passed by creamish white Saturn. This month, another interesting conjunction occurs on September 27th when Mars passes 3 degrees north of red supergiant Antares (α Sco - mag. +1.0), the brightest star in Scorpius. Antares is often referred to as the "Rival of Mars" and the two should appear very similar to the naked eye, although Mars will be marginally brighter at magnitude +0.8.
On September 29th, the waxing crescent Moon passes 3 degrees north of Mars.
Jupiter. mag. +1.9, is now a brilliant morning object moving direct amongst the stars of Cancer. At the beginning of September, the dominant planet in the Solar System rises over 2 hours before the Sun increasing to over 4 hours by months end.
The planet dominates a relatively barren part of the sky although the twins of Castor (α Gem - mag. +1.6) and Pollux (β Gem - mag. +1.1) are positioned about 20 degrees northwest of Jupiter. Since moving into the morning sky, this is probably the first month when telescope users have enough observing time to study the planet in detail. As the year progresses, Jupiter will continue to brighten and increase in apparent size as it moves towards opposition early next year.
On September 20th, the waning crescent Moon passes 5 degrees south of Jupiter.
Saturn, mag. +0.6, remains an early evening object in Libra throughout the month. On September 1st, the "Ringed planet" appears rather low down above the southwestern horizon from northern temperate latitudes, setting about 2 hours after the Sun. However, it's much better placed from Southern Hemisphere locations, where it appears higher in the sky and sets much later at around midnight.
On the first day of the month, Mars (mag. +0.6) is positioned 5 degrees southeast of Saturn but as its much closer to Earth and traveling on a faster trajectory, it's not long before Mars distances itself from Saturn.
By months end, for northern-based observers Saturn will be rather low down at dusk but better placed and easier to see for observers located further south. On September 28th, the waxing crescent Moon passes 0.7 degrees north of Saturn and an occultation is visible from Hawaii, southwestern Alaska and the Pacific Ocean (4:25 UT).
Uranus, mag. +5.7, is now closing in on next month's opposition. The planet is moving slowly retrograde in Pisces and at the start of September rises in the east less than two hours after sunset. The period of visibility continues to improve as the month progresses and by month's end, Uranus is practically visible all night.
A good starting point to find Uranus is the "Great Square of Pegasus". Uranus is positioned about 25 degrees southeast of the centre of the square. The stars ε Psc (mag. +4.3) and δ Psc (mag. +4.4) are positioned 2 degrees northeast and 2 degrees northwest of Uranus respectively.
Uranus has an apparent diameter of 3.7 arc seconds and a small telescope at high magnification will show a small green disk that's obviously non-stellar. However, even when viewed through the largest amateur scopes it's difficult to make out any surface details on Uranus.
On September 11th the waning gibbous Moon passes 1 degree north of Uranus.
Neptune is located in Aquarius and has recently just past opposition (August 29th). The distant planet is moving very slowly retrograde and remains well placed for observation during September, visible as soon as it's dark enough until just before sunrise. At magnitude +7.8, Neptune is the only planet that can't be glimpsed with the naked eye (under dark skies Uranus can be seen), however it can be spotted relatively easily with binoculars or small telescopes.
The constellation Aquarius lies between the Great Square of Pegasus and the barren starfields of Capricornus and Piscis Austrinus. It contains mostly faint stars but locating Neptune is not difficult once you have identified sigma Aqr (σ Aqr -mag. +4.8). Neptune is positioned about a degree to the north with the planet being 15x fainter than the star.
On September 8th, the almost full Moon passes 5 degrees north of Neptune.
M99 is a magnitude +10.2 spiral galaxy situated in the southern part of the constellation of Coma Berenices. It's a beautiful object that's a member of the Virgo cluster of galaxies and appears almost face-on from our perspective. M99 was discovered by Pierre Mechain on March 15, 1781, on the same night he also discovered M98 and M100. The discoveries were then reported to Charles Messier, who measured the positions before adding them to his catalogue on April 13, 1781. This was just prior to the release of the third and final published edition.
The 3rd Earl of Rosse, William Parsons, first identified the spiral structure of M99 in 1846 using his 72-inch (1.83 m) reflecting telescope at Birr Castle in Ireland. The galaxy was one of the first to have its structure identified. At the time, Rosse was using the World's largest optical telescope.
M99 is located 55 Million light-years from Earth. It covers 5.3 x 4.6 arc minutes of apparent sky, which corresponds to a spatial diameter of 85,000 light-years. The galaxy is positioned 7 degrees east of bright star Denebola (β Leo - mag. +2.1) and just less than 1 degree southeast of star 6 Com (mag. +5.1). Tenth magnitude edge-on spiral galaxy M98 lies 0.5 degrees west of 6 Com.
If you live in the Northern Hemisphere the next few weeks offer a superb opportunity to spot Comet Jacques. The comet appears high in the sky and passes just north of the famous and easily recognisable "W" of Cassiopeia. Although not visible to the naked eye, Jacques shines at 7th magnitude and therefore within the range of binoculars and small telescopes.
Jacques was discovered by Cristovao Jacques, Eduardo Pimentel and Joao Ribeiro de Barros on March 13, 2014, shining at a dim magnitude +14.7. The comet passed perihelion on July 2nd when it approached to within 0.66 AU (99 million kilometres or 61 million miles) of the Sun. On August 28th, Jacques will pass closest to the Earth at distance of 0.56 AU (84 million kilometres or 52 million miles). It will be visible in Cepheus at magnitude +7.5 on this day.
Location and star chart
Before, during and after flyby of Earth, Jacques moves at it's fastest against the "fixed" background stars. The comet began August in the constellation Auriga before moving into Perseus on August 5th. It then passed into Camelopardalis on August 14th remaining there for a few days before moving into Cassiopeia on the 18th. Jacques is currently moving westwards and between August 22nd and 26th passes about 5 degrees north of the Cassiopeia "W" asterism. With a declination of 60+ degrees north during this time, Jacques is circumpolar and hence visible all night from latitudes of 30N or more. On August 26th, the comet moves into Cepheus where it remains for the rest of the month. It will pass 0.5 degrees south of Herschel's famous Garnet Star (μ Cep - mag. +4.1(v)) on the last day of the month. From southern temperate latitudes, Jacques won't be visible again until early September.
The comet is expected to fade from magnitude +6.5 to +7.6 during August. So far it has put on a fine show with a nice coma and small tail visible through binoculars and small telescopes. Photographically it looks green in appearance.
The finder chart below shows the positions of Jacques from August 22 to August 31, 2014.
M98, mag. +10.4, is a large beautiful edge-on spiral galaxy that's located in the southern section of the constellation of Coma Berenices. It's one of the fainter Messier objects and a medium sized amateur telescope or greater is recommended. The galaxy is a member of the Virgo cluster and was discovered by Pierre Mechain on March 15, 1781. On the same night he also discovered M99 and M100. Messier catalogued them shortly afterwards and remarked that M98 was the faintest of the three.
M98 is one of a small group of galaxies that are blueshifted. The vast majority of galaxies are receding from us and display redshifts but due to the movement of M98 within the Virgo cluster, it's currently falling towards us, hence the blueshift. The galaxy is located about 57 Million light-years distant and has an apparent size of 9.8 x 2.8 arc minutes. This corresponds to an actual diameter of 160,000 light-years. It's estimated to contain 1 trillion stars.
Pinpointing the area of sky where M98 is located is easy. It's located 6 degrees east of Denebola (β Leo - mag. +2.1) the third brightest star in Leo. The star 6 Com (mag. +5.1) lies 0.5 degree east of M98 and acts as a perfect marker.
The Virgo cluster galaxies are best seen during the months of March, April and May.
M102 is a galaxy catalogued by Charles Messier that hasn't been explicitly identified. It was Pierre Mechain who made the original observation in March 1781 before passing the information onto Messier, who catalogued it without verification. However, Mechain himself believed M102 was an error and wrote a letter on the May 6, 1783 expressing his view that the object was in fact a duplicate entry of M101. The story does not end there, historical evidence based on Messier description of the galaxy combined with its co-ordinates suggest that M102 could well be lenticular galaxy NGC 5866, also known as the Spindle galaxy. A number of other possible candidates have been suggested but it seems both Messier and Mechain have observed NGC 5866 in the past and therefore we list it as the missing item.
The Spindle galaxy (mag. +9.9) is located at the southern edge of the far northern constellation of Draco. It's positioned four degrees southwest of star Iota Draconis (ι Dra - mag. +3.3). Directly west of NGC 5866 are the seven stars that form the famous "Plough" or "Big Dipper" asterism of Ursa Major.
NGC 5866 is a challenging binocular object but easier to spot with small scopes. It's best seen from the Northern Hemisphere during the months of April, May and June. From latitudes of 35N or greater, the galaxy is circumpolar and therefore never sets.
M86 is a giant lenticular or elliptical galaxy located in Virgo that's one of the brighter galaxies in the Virgo cluster (mag. +9.3). It lies at the heart of the grouping and forms a conspicuous pair with close neighbour and almost twin, M84. Through a medium sized scope, M86 appears as a bright, elongated patch of light. Also visible in the same low/medium power eyepiece field of view is M84.
It's currently not 100% certain what type of galaxy M86 is, it could be either a type S0 lenticular galaxy or an elliptical galaxy of type E3. The galaxy is unusual in that it's blue shifted and hence moving towards the Milky Way. Due to the expansion of the Universe most galaxies are receding and show redshifts. However, M86 is falling towards the centre of the Virgo cluster, causing it to move towards us at a speed of 244 km/s. This resulting blueshift is the highest of all Messier objects.
M86 was discovered by Charles Messier on March 18, 1781. This was an extremely productive night for Messier since he also discovered another seven Virgo cluster members and rediscovered globular cluster M92 in Hercules. The galaxy has an apparent diameter of 8.9 x 5.8 arc minutes and at a distance of 52 million light-years this corresponds to a spatial diameter of 135,000 light-years. It's estimated to contain at least 400 billion stars.
M86 is positioned close to the Virgo-Coma Berenices constellation border and can be found by imagining a line connecting Denebola (β Leo - mag. +2.1) with Vindemiatrix (ε Vir - mag. +2.8). Towards the centre of this line is M86 and positioned 17 arc minutes west of M86 is M84.
The galaxies are best seen during the months of March, April and May.
M60 is an elliptical galaxy and a member of the Virgo cluster of galaxies. With an apparent magnitude of +9.2 it's the third brightest of the giant elliptical galaxies in the Virgo cluster. Only M49 (mag. +8.4) and M87 (mag. +8.7) appear more luminous from our perspective. M60 is visible with small scopes or large binoculars, but as with most galaxies it's better seen with greater aperture.
On April 11, 1779 while comet chasing, Johann Gottfried Koehler discovered M60 together with its slightly smaller and fainter neighbour M59. Also searching around the same time and the same part of the sky was none other than Charles Messier, who independently found both M59 and M60 four days after Koehler. During his search, Messier also discovered M58, another nearby Virgo cluster galaxy that was missed by Koehler. Of the three galaxies, Messier described M60 as the brightest with M59 and M58 being fainter and of similar magnitude.
Locating M60 is relatively easy. Start by imagining a line from Vindemiatrix (ε Vir - mag. +2.8) heading in the direction of Denebola (β Leo - mag. +2.1). About 4.5 degrees along this line is M60 with M59 positioned 0.4 degrees west of M60. Moving another degree in the same westerly direction arrives at M58.
M60 is estimated to lie 55 million light-years from Earth. It spans 7.6 x 6.2 arc minutes of apparent sky, which corresponds to a spatial diameter of 120,000 light-years. The galaxy contains about 400 billion stars and is best seen during the months of March, April and May.
M17 also known as the Omega Nebula is a bright emission nebula located in the rich Milky Way star fields of Sagittarius. It's a H II star formation region that shines with an apparent magnitude of +6.0, placing it at the limit of naked eye visibility. Through binoculars, M17 appears as a diffuse patch of light that's oval shaped. In the same field of view to the south are open cluster M18 (mag. +7.5) and the very large Sagittarius Star Cloud (M24 - mag. +4.6).
The Omega Nebula is located 5,500 light-years from Earth. Embedded within it is an open cluster of at least 35 stars that provides the source of the glowing gas. In many similar nebulae such stars are relatively easily visible, but not so in the case of M17. They are hidden deep within the structure and are not obvious. In total, there are many hundreds of stars contained in the nebula itself.
M17 was discovered by Philippe Loys de Chéseaux sometime between 1745-46. Charles Messier independently rediscovered it on June 3, 1764. The nebula covers 20x15 arc minutes of apparent sky, which corresponds to an actual diameter of 32 light-years. It's also sometimes referred to as the Swan Nebula, Horseshoe Nebula, Checkmark Nebula or Lobster Nebula.
The Omega Nebula is positioned at the very north of Sagittarius, close to the Serpens Cauda and Scutum constellation boundaries. It's located about 15 degrees north of the "teapot" asterism of Sagittarius. A couple of degrees south of M18 is M24 with M17 sandwiched between them. The star γ Sct (mag. +4.7) lies 2 degrees northeast of M17 with M16 the Eagle Nebula located 2.5 degrees west of this star.
The objects are best seen from southern and equatorial regions during the months of June, July and August.
Comet Jacques is now gradually fading in brightness but is currently superbly placed for observation from Northern Hemisphere latitudes. The comet started August in Auriga and at magnitude +6.7 was easily within binocular and small telescope range. Through the eyepiece it displayed a bright condensed coma with a short tail.
Location and star chart
Jacques is currently continuing on its northwesterly path and moved into Perseus on August 5th where it remains until the 15th. On this date, the comet passes into the faint constellation of Camelopardalis and is expected to have faded slightly to magnitude +6.8. It then moves into Cassiopeia on August 19th before crossing into Cepheus on August 27th, where it stays for the remainder of the month.
From northern latitudes, the comet is visible during August high in the sky towards the east in the early hours of the morning. The visibility improves as the month progresses. From latitudes of 40N or greater, Jacques is circumpolar during the second half of August, hence never setting. It should remain within binocular range although by months end is expected to have faded to magnitude +7.4
From Southern Hemisphere latitudes, the comet won't be visible again until early September. The finder chart below shows the positions of Jacques from August 11 to August 22, 2014.