This page provides some astronomical information on a monthly basis for those of you living in the United Kingdom. Timings are in GMT (Greenwich Mean Time) unless otherwise noted. York will be used as a representative location for the United Kingdom. Latest additions or updates are highlighted with a red border.
This month we have sections on:
Additional information on phases of the Moon, seasons, summer times, eclipses, chronological cycles and eras, religious holidays, the United Kingdom civil calendar and holiday dates can be found in HMNAO's Astronomical and Calendarial Sheet for 2018. This is a pdf document for which a document reader can be downloaded by clicking on the Adobe Reader icon above.
↻ The last update to this page was made on Friday, 2018 February 16 at 08:29:30 GMT.
An animated view of the Sun's disk over the last twenty-eight days is shown in the image on the left. North is at the top of the image and east is to the left. These images come from the Helioseismic and Magnetic Imager instrument on the NASA Solar Dynamics Observatory (SDO) satellite. More multi-wavelength data from the SDO can be found here.
The Sun has been devoid of active regions for a total of eighteen days this year, bringing the number of spotless days for 2018 to 38% of the year so far. The latest run of spotless days was ended by the appearance of the active region AR2699 on Sunday February 4th which is now approaching the western limb of the Sun. AR2699 became a quadruple-cored feature and doubled in size within a couple of days of its first appearance. However, it has now decayed to a single-cored feature and poses no significant threat of solar flare activity. The magnetic canopy of AR2699 erupted in the early hours of Monday February 12th, a process which lasted more than six hours, producing a minor C1-class solar flare and an Earth-directed coronal mass ejection (CME). This CME reached the Earth on February 15th causing polar auroral displays, e.g. in northern Norway. There is a coronal hole located just to the north west of the centre of the Sun's disk. Solar winds from this feature are expected to reach the Earth on February 16th-17th. The combined effect of the solar wind and the wake of the CME could lead to more geomagnetic storms and polar auroral activity. Overall solar activity remains at very low levels.
NASA reported that a reversal of the Sun's magnetic field took place at the start of 2014 indicating that the maximum of solar cycle 24 had been reached. A plot of sunspot numbers, both observed and predicted versus time indicates that this solar maximum is more complex than had been previously predicted. The maximum is double-peaked in a similar manner to that of the previous maximum of 2001/2002. The individual peaks occurred in 2011 and 2014 with the latter being the larger of the two. However, sunspot numbers are significantly down on the predictions made for this maximum — indeed solar cycle 24 may be the weakest in the last 100 years or so i.e. since solar cycle 14. Assuming the start of 2014 was the beginning of the post maximum phase of solar cycle 24, we are now well into the decreasing phase of activity where individual energetic events can spawn some of the most powerful flares and coronal mass ejections of the cycle. The so-called Carrington event of 1859 is a good example of just what might be expected from this type of violent outburst. The next solar minimum, characterized by periods of many days without sunspots and flare activity, may occur in 2019 or 2020. It is likely to be a deep minimum with long periods without much sunspot or flare activity. Space weather will be dominated by solar winds and cosmic rays rather than sunspots and solar flares.
The sequence of Moon phases for this month and their designations are shown in the following animation:
|Moon phases for February 2018 are as follows:|
|Last Quarter||—||Wednesday February 7th at 15:54 GMT|
|New Moon||—||Thursday February 15th at 21:05 GMT
|First Quarter||—||Friday February 23rd at 08:09 GMT|
The Moon is at apogee (furthest from the Earth) on Sunday February 11th at 14:16 GMT when it is 405,700km from the Earth. It is at perigee (closest to the Earth) on Tuesday February 27th at 14:39 GMT when it is 363,933km from the Earth.
You can see there is no Full Moon in February 2018. The lack of a full moon in February is sometimes known as a "Black Moon". There are several definitions of this term. One is the second occurrence of a new moon in a calendar month. It can also be the third new moon in a season of four new moons. Both of these are analogous to the "blue moon" definitions covered last month. The third is the absence of a full moon in a calendar month and the fourth is the absence of a new moon in a calendar month. The last two can only happen in February in addition to the previous January and the following March having two full or new moons respectively. February 2018, is an example of the third definition which occurs about once every 19 years.
On Thursday February 1st, the Moon occults Regulus, the bluish-white first-magnitude star in the constellation of Leo. This occultation by the nearly full moon is visible from Scandinavia, northern Greenland, Svalbard, northern and eastern Russia, north-east China, north-west Alaska and most of Japan. The end of this occultation (the re-emergence phase) is visible from northern Scotland and the Orkney and Shetland Islands at around moonrise. The occultation is not visible from the remainder of the United Kingdom.
On Friday February 23rd, the Moon continues its current series of occultations of Aldebaran, the orange first-magnitude star in the constellation of Taurus. This occultation by the first quarter moon is visible from Bermuda, north-eastern parts of North America, Greenland, most of Europe (including the British Isles), Svalbard, most of Russia, Kazakhstan, western Mongolia and north-west China. This occultation is visible from York, starting (disappearance phase) at 16:37 UT and ending (re-emergence phase) at 17:46 UT.
Please follow the New Moon link above to take part in our Crescent Moon Watch program which involves sighting the new crescent moon as early as possible after the instant of New Moon.
If you want to know what the Moon looks like now, try this USNO page generated by our colleagues in the Astronomical Applications Department at the US Naval Observatory in Washington.
There are five eclipses in 2018, two are total eclipses of the Moon and the remaining three are partial eclipses of the Sun. One total eclipse of the Moon is visible in the United Kingdom, namely that of 2018 July 27th. One partial eclipse of the Sun is also visible from the northernmost parts of the United Kingdom on 2018 August 11th.
A total eclipse of the Moon occurred on Wednesday January 31st 2018. It was visible in its entirety from Alaska, western Canada, the Hawaiian Islands, western Polynesia, Melanesia, Micronesia, most of Australia, New Zealand, eastern Indonesia, the Philippines, eastern China, Japan and eastern Siberia. Western parts of the United States, western China and India also saw the total phase of the eclipse. The eclipse ended just before moonrise in the United Kingdom so it was not visible in the United Kingdom. Photographs of this eclipse taken around the end of totality show the effect of atmospheric scattering (left-hand image – red colouration) and ozone in the Earth's stratosphere (right-hand image – turquoise colouration).
A partial eclipse of the Sun will occur on Thursday February 15th 2018. It will be visible in its entirety from most of Antarctica except parts of eastern Antarctica including Enderby Land, American Highland and Wilkes Land, and the southern part of South America including Argentina and the southern half of Chile. This eclipse is not visible from the United Kingdom.
A partial eclipse of the Sun will occur on Friday July 13th 2018. It will be visible from the easternmost part of Wilkes Land in Antarctica, the southern tip of New Zealand and the southernmost parts of South Australia and Tasmania. This eclipse is not visible from the United Kingdom.
A total eclipse of the Moon will occur on Friday July 27th 2018. It will be visible in its entirety from the Indian Ocean region, westernmost China, India, the Middle East, central Asia, Turkey and the eastern half of Africa. Most of Australia, the Philippines, Indonesia, most of China, western Africa and most of Europe will see the total phase of the eclipse. Some of the total phase of the eclipse is visible from the United Kingdom as the Moon rises during the umbral part of the eclipse. In York, the Moon rises at 21:04 BST, approximately halfway between the start of the total phase at 20:30 BST and the middle of the total phase at 21:22 BST. The Moon will rise in a totally-eclipsed state and we will see about three quarters of the total phase of the eclipse.
A partial eclipse of the Sun will occur on Saturday August 11th 2018. It will be visible in its entirety from north-easternmost parts of Canada, Greenland, Iceland, northern Scotland, Scandinavia except Denmark, most of Russia except the south-western and eastern parts, and central Asia. In the United Kingdom, this eclipse is visible from the northernmost parts of Scotland, the Orkney Islands and the Shetland Islands as a very small partial eclipse with an obscuration of less than 1.8%. The eclipse will last 30 to 40 minutes with maximum obscuration occurring at around 9:49 BST. The eclipse is not visible from the remainder of the UK.
Further information on all the eclipses in 2018 can be found on the Eclipses Online web pages. This web site provides information on both solar and lunar eclipses in the period from 1501 CE to 2100 CE. Global circumstances of both solar and lunar eclipses are provided as well as local circumstances of the solar eclipses based on a gazetteer of approximately 1500 locations worldwide. Eclipses for next year, 2019, are also available.
Mercury is extremely low in the east south-eastern morning twilight sky shortly before sunrise for the first week or so of the month. It disappears into the Sun's glow as it reaches superior conjunction on Saturday February 17th. Mercury reappears very low in the west south-western sky during evening civil twilight for the last week of the month, climbing higher in the sky for a rendezvous with Venus on Monday March 5th. At the start of the month its magnitude is around −0.8 and by the end of the month it brightens to around −1.4.
Venus is too close to the Sun to be observed for most of this month. It will not reappear in our skies until the end of the third week of February when it will be visible, perhaps with difficulty, in the twilight glow as a brilliant object in the western sky at the end of evening civil twilight. Venus climbs higher in the twilight sky during the last week of February as it moves towards a rendezvous with Mercury on Monday March 5th.
Mars rises around three and a half hours before the start of morning nautical twilight in the south-eastern twilight sky. It lies in the constellation of Scorpius for the first week or so of February. Mars then moves eastwards into Ophiuchus for the remainder of the month. It brightens somewhat from magnitude +1.2 at the start of the month to +0.9 at the end of February. Mars lies 4° south of the waning crescent moon on Friday February 9th and 5° north of the red first-magnitude star Antares (α Scorpii) on Saturday February 10th. With Mars and Antares being of similar colours and magnitudes, Antares really is the "Rival of Mars".
Jupiter rises nearly five hours before the start of morning nautical twilight in the east south-eastern twilight sky. It lies in the constellation of Libra where it will remain for much of 2018. Jupiter brightens somewhat from magnitude −2.0 at the start of the month to −2.2 at the end of February. It lies 4° south of the waning crescent moon on Wednesday February 7th.
Saturn rises in the south-eastern twilight sky about an hour before the start of morning nautical twilight. It lies in the central part of the constellation of Sagittarius where it will remain for the remainder of 2018. Saturn's magnitude remains constant at +0.6 for the whole of February. It lies 2° south of the new crescent moon on Sunday February 11th.
Uranus rises in the east north-eastern sky about two hours after sunrise and lies in the south-western sky at the end of evening nautical twilight. It lies in the constellation of Pisces approximately 3° to the west of the 4th magnitude star Omicron Piscium. Uranus is blue-green object of magnitude +5.8 visible with binoculars at the start of the month fading slightly to +5.9 by the end of February. This planet can also be glimpsed with the naked-eye under optimum conditions.
Neptune rises in the east north-eastern sky less than an hour after sunrise and is close to the south-western horizon at the end of evening nautical twilight. It lies in the constellation of Aquarius approximately 1.5° to the east of the 4th magnitude star Lambda Aquarii. Neptune is getting closer to the Sun as it approaches conjunction on Sunday March 4th. Neptune is a bluish object of magnitude +8.0 visible with good binoculars under optimum conditions. However, please note that it can be difficult to distinguish Neptune from other stellar objects of a similar magnitude.
Pluto lies in the constellation of Sagittarius and is too close to the Sun to be observed this month. Strictly speaking, this is a dwarf planet as it got demoted from the ranks of the "bona-fide" planets in 2006. I have to confess that I was one of those astronomers that voted for its demotion at the IAU General Assembly in Prague! At magnitude +14.6, you are going to need a much more serious telescope to see this remote member of the Solar System.
The rarely-spotted Zodiacal Light can be seen in the half hour or so before astronomical twilight starts in the morning or in the half hour or so after astronomical twilight ends in the evening. It is best seen when the ecliptic, the path the Sun takes in the night sky, is at a steep angle to the horizon. In northerly latitudes, this occurs in the western evening post-twilight sky in February and March and the eastern morning pre-twilight sky in September and October. The Zodiacal Light appears as a large, softly radiant pyramid of light with its base near the horizon and its axis centred on the Zodiac constellations. It appears to be about as bright as the Milky Way, so a dark, unpolluted sky without haze is essential to see this phenomenon. Beware, it can easily be confused with twilight itself. In the accompanying photograph, the Zodiacal Light is on the left and the Milky Way is on the right. For York, astronomical twilight ends in the evening at around 18:50 GMT at the beginning of the month and at 19:35 GMT at the end of the month. The cause of this so-called "false dawn" is sunlight reflecting of a lens-shaped cloud of dust in the plane of the inner solar system.
There are no major meteor showers active during February. The next significant shower is the April Lyrids, active during the latter half of April and peaking on Sunday April 22nd at around 18:00 UT, displaying a rate of about 20 meteors per hour. This year's display is reasonably well-aspected for morning observations as the maximum occurs close to first quarter moon. Further information can be found at the International Meteor Organization and their 2018 Meteor Shower Calendar.
It is worth noting that bright sporadic meteors and fireballs are possible at any time e.g. the fireball observed over many parts of England and Scotland on Saturday March 3rd 2012 at 21:40 GMT. Larger events, known as bolides, are rarer. Typically, this is a very bright fireball reaching an apparent magnitude of −14 or so, perhaps three times as bright as a full moon. Even rarer are the superbolides, events with apparent magnitudes of −17 or so, around 50 times brighter than the full moon. A recent example of a superbolide was the Chelyabinsk meteor of 2013 February 15th at 03:20 UTC which may have been a 20-metre diameter near-Earth asteroid.
Another loosely-related phenomenon is the re-entry of space debris from space vehicles and satellites whose orbits are decaying to the point where they burn up in the Earth's atmosphere. A couple of well-reported examples of this occurred at around 23:00 BST on Friday September 21st 2012 as well as the return of the GOCE satellite just after midnight on Tuesday November 12th 2013.
There are a number of comets around the sky at the moment. However, most of them require telescopic assistance to see them and some may be too far south in the sky to be seen by observers based in the United Kingdom. Here is a brief summary of the comets that may be accessible to observers with binoculars or small telescopes in the northern hemisphere.
A possible target for the observer with access to a small telescope is the comet C/2017 T1 Heinze. It was closest to the Earth on Thursday January 4th at a distance of 33 million kilometres from the Earth reaching a magnitude of 9.8. During February, it lies in the constellation of Pegasus. It was discovered on 2017 October 2nd and will reach perihelion on 2018 February 21st. The magnitude of this comet would suggest that it exceeds the Bortle limit for comets, indicating that it may not survive its passage through perihelion. Nevertheless during the first half of February, it should be visible low in the western evening sky at the end of nautical twilight before disappearing into the Sun's glow as it approaches perihelion.
The tenth-magnitude comet C/2016 R2 PANSTARRS has recently exhibited some unusual behaviour. For those of you with access to a small telescope, it may be of interest to take a look at this comet. It remains in the constellation of Taurus, not too far from the Pleiades open cluster for the whole of February, In this photograph, the comet lies between the 4th magnitude star Gamma Tauri (bottom left) and the seventh magnitude star HD27029 (top right). It has a very strong blue colour indicative of significant quantities of ionised carbon monoxide, CO+, fluorescing under the influence of sunlight in its orbit just outside that of Mars. It has a chaotic tail fed by jets from the comet's core; the tail also exhibits swirls of material and an unusual knee-shaped feature. The comet can be seen high in the southern sky at the end of evening nautical twilight and there is plenty of scope for more volatility as carbon monoxide-rich C/2016 R2 reaches perihelion on 2018 May 9th.
If you want to look for the International Space Station (ISS) as it passes over your location, please have a look at the Heavens Above web site. Choose your observing location in the Configuration section and then select ISS in the Satellites section. The ISS is at least as bright as a first magnitude star and can approach the brightness of Venus. Similarly, if you want to look for the Chinese space stations, Tiangong-1 and Tiangong-2 by selecting the appropriate links. It has been known for some time now that Tiangong-1 will re-enter the Earth's atmosphere in an "uncontrolled manner" early in 2018, most likely in March. Tiangong-1 and Tiangong-2 are significantly fainter than the ISS, normally as bright as a third or fourth magnitude star. Predictions for other satellites obtained from the Heavens Above web site.
Another satellite-related phenomena to look out for are the so-called "Iridium flares". These bright flashes of sunlight reflecting off the Iridium series of communication satellites can be seen at night and also occasionally during the daytime if they are bright enough. Predictions for the next seven nights can be obtained from the Heavens Above web site by setting your observing location in the Configuration section and then selecting Iridium Flares in the Satellites section.
The above image is a 30 minute forecast of the location and probability of auroral activity based loosely on a model developed at Johns Hopkins' Applied Physics Laboratory known as the Ovation Aurora Forecast model. It provides estimates of the energy per unit area on the Earth's atmosphere from observations of the solar wind and interplanetary magnetic field made by the Advanced Composition Explorer satellite in conjunction with empirical relationships derived from the Defense Meteorological Satellite Program. It shows where the aurora is most likely to be seen and how bright it is likely to be. The model generates a global estimate of power, called the Hemispheric Power, deposited into the atmosphere in gigawatts (GW). For powers of less than 20GW, little or no aurora may be visible. For powers of 20-50GW, you may need to be relatively close to the aurora to see it. For values above 50GW, the aurora should be easily observable, active and mobile. For values above 100GW, this is considered to be a significant storm where the aurora may be visible from hundreds of miles away. The current prediction is downloaded when you load this page. If you want to download the latest model, simply reload this page or hit F5. If you want to see the full-sized map, please click on the above image.
The above sky chart, generated from the Heavens-Above.com web site, shows what the night sky looks like at 22:00 GMT on Wednesday February 14th 2018 from York. The night sky will look the same an hour later at 23:00 GMT at the beginning of the month and one hour earlier at 21:00 GMT at the end of the month. Please click on the chart to see a full-sized sky chart image. If you want to generate your own star chart for another combination of location, date and time, please have a look at the Heavens Above web site. Choose your observing location in the Configuration section and then select Sky Chart in the Astronomy section.
Rising and setting times for the Sun and Moon as well as the planets and the times of twilights for other locations in the United Kingdom can be obtained from HMNAO's Websurf web pages using the Rise, Set and Twilight Times option.
The actual times at which the Sun will just appear, or disappear, will depend on the difference of the altitudes of the observer and the local horizon and the actual refraction, which depends on the meteorological conditions along the light path. Differences of a minute or so from the tabulated times are to be expected.
For the drivers amongst you, the "Hours of Darkness", as defined by the Road Vehicle Lighting Regulations (1989), start half an hour after sunset and end half an hour before the following sunrise. Headlights should be used during the Hours of Darkness and sidelights in the half hour periods after sunset and before sunrise. These timings can also be obtained from HMNAO's Websurf web pages using the Rise, Set and Twilight Times option.
For the VFR (Visual Flight Rules) pilots amongst you, night, according to Statutory Instrument 2009 No. 3015, Civil Aviation, The Air Navigation Order 2009, Part 33 (Interpretation), Article 255(1), means "the time from half an hour after sunset until half an hour before sunrise (both times inclusive), sunset and sunrise being determined at surface level". In other words, the night time period starts at the beginning of the Hours of Darkness and finishes at the end of the Hours of Darkness.