This page provides some astronomical information on a monthly basis for those of you living in the Taunton area. Timings are in GMT (Greenwich Mean Time) unless otherwise noted. Latest additions or updates are highlighted with a red border.
This month we have sections on:
The Earth reaches perihelion, the point closest to the Sun in its orbit, on Saturday January 2nd at 13:51 GMT when it is 147,093,163 km from the Sun.
Additional information on the phases of the Moon, the seasons, summer times, eclipses, chronological cycles and eras, religious calendars, the civil calendar and holiday dates in the United Kingdom can be found in HMNAO's Astronomical and Calendarial Sheet No. 108 for 2021. This is a pdf document for which a document reader can be downloaded by clicking on the Adobe Reader icon above.
This web page can also be accessed from outside the UK Hydrographic Office on http://astro.ukho.gov.uk/nao/taunton.html.
↻ The last update to this page was made on Friday, 2021 January 22 at 12:10:29 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 visible disk of the Sun has two active regions on it, AR2797 and AR2798. The former has split into two groups, the trailing group is now designated AR2798 which is also exhibiting a significant number of minor B-class solar flares. AR2797 is now a twin core feature which is quiet and unlikely to produce strong solar flares. The total number of spotless days for 2021 remains at twelve, or 55% of the year so far. Solar winds are currently blowing with velocities of around 310km/s and the planetary Kp geomagnetic activity index is likely to peak at 1 (quiet) today. There is a new coronal hole close to the centre of the Sun's disk. Solar winds emanating from this feature could reach the Earth on January 25th–26th. Streams of solar wind from the previous coronal hole missed the Earth, probably passing over the planet's north pole. Predicted geomagnetic storms are therefore very unlikely to occur. Satellite observations indicate that a new sunspot may appear over the north-eastern limb of the Sun in the next 48 hours. The overall amount of 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 the solar maximum of Solar Cycle 24 was more complex than had been previously predicted. The maximum was 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 were significantly down on the predictions made for the maximum — indeed Solar Cycle 24 may be the weakest in the last 100 years or so i.e. since Solar Cycle 14.
The declining phase of the solar cycle brings increased numbers of cosmic rays to the Earth, an increased frequency of 'pink' aurorae and a slight dimming of the Sun of approximately 0.1% in terms of the total solar irradiance. TSIS-1 was launched on December 15th 2017, which will monitor the Sun over a five-year period covering the whole of the current solar minimum. Cooling and contraction of the Earth's upper atmosphere in response to the changes on the Sun due to the solar minimum also delayed the orbital decay of satellites such as the Chinese space station, Tiangong 1, which returned to Earth on Monday April 2nd 2018 at 00:16 UTC. The Sun's magnetic field and solar winds provide some protection for the Earth from cosmic rays. A recent paper in the journal Space Weather claims that this solar minimum could see a rise in the number of cosmic rays reaching the Earth by as much as 30% due to the weakening magnetic field of the Sun and reduced levels of solar winds. This could mean an increased risk of radiation exposure for travellers on commercial airlines and possible changes to the climate.
During the post maximum phase of the solar cycle individual energetic events can spawn some of the most powerful flares and coronal mass ejections of the cycle. The so-called Carrington event on September 1st–2nd 1859 during Solar Cycle 10 is a good example of just what might ensue from this type of violent outburst. On 2020 September 15th NASA and NOAA announced that a minimum of the Sun's activity had been reached in December 2019 bringing to an end the old Solar Cycle 24. Predictions are that the new Solar Cycle 25 will be a weak one, similar to its predecessor, peaking in 2025. 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 flare activity.
The sequence of Moon phases for this month and their designations are shown in the following animation:
|Moon phases for January 2021 are as follows:|
|Last Quarter||—||Wednesday January 6th at 09:37 GMT|
|New Moon||—||Wednesday January 13th at 05:00 GMT
|First Quarter||—||Wednesday January 20th at 21:02 GMT|
|Full Moon||—||Thursday January 28th at 19:16 GMT
The Moon is at perigee (i.e. nearest to the Earth) on Saturday January 9th at 15:37 GMT when it is 367,387 km from the Earth. It is at apogee (i.e. furthest from the Earth) on Thursday January 21st at 13:11 GMT when it is 404,360 km from the Earth.
Please follow the New Moon link above to find out more about our Crescent Moon Watch program which involves making sighting of the new crescent moon as early as possible after the instant of New Moon.
There are four eclipses visible from the Earth during 2021 — two lunar eclipses, one total and one partial and two solar eclipses, one annular and one total. Parts of two of the eclipses are visible from the United Kingdom, namely the partial phase of the annular eclipse of the Sun and some of the partial eclipse of the Moon. The total eclipses of the Sun and Moon are not visible from the United Kingdom.
A total eclipse of the Moon occurs on Wednesday May 26th 2021. It is visible in its entirety from south-westernmost Alaska, the Aleutian Islands, the Hawaiian Islands, Polynesia, the central Pacific Ocean region, New Zealand, Melanesia, Micronesia, central and eastern Australia and parts of Antarctica. Parts of the eclipse are visible from the Americas except north-eastern Canada and eastern parts of South America, Indonesia, the Philippines, Japan, eastern Asia, north-easternmost Russia and the eastern half of the Indian Ocean. The eclipse begins at 08:46 UT and ends at 13:51 UT. The Moon enters the umbral shadow at 09:45 UT. Totality begins at 11:10 UT and ends at 11:28 UT. The Moon leaves the umbral shadow at 12:53 UT. The eclipse is not visible from the United Kingdom.
An annular eclipse of the Sun occurs on Thursday June 10th 2021. It is visible as a partial eclipse from the north-eastern part of North America, the Arctic Ocean, most of Greenland, Iceland, northern Europe (including the British Isles), Scandinavia, most of Russia, Mongolia and most of China. The path of annularity begins over central Ontario and crosses over north-western Quebec, the southern part of Baffin Island, the north-western part of Greenland, the North Pole (for the only time this century) and the north-eastern part of Siberia. The eclipse begins at 08:12 UT and ends at 13:11 UT. The annular phase starts at 09:50 UT and ends at 11:33 UT. The maximum duration of annularity of 3m 48s takes place at 10:42 UT over the sea between Ellesmere Island and north-western Greenland. From Taunton, the partial eclipse starts at 10:04 BST and ends at 12:18 BST. The maximum obscuration occurs high in the south-eastern sky at 11:08 BST when 21.4% of the Sun is obscured.
A deep partial eclipse of the Moon occurs on Friday November 19th 2021. It is visible in its entirety from most of North America except the easternmost parts, Mexico, the eastern and central Pacific Ocean regions and north-eastern parts of Russia. Parts of the eclipse are visible from Scandinavia, the British Isles, Iceland, South and Central America, Australasia, Japan, the Philippines, most of Indonesia, eastern and northern Asia. The eclipse starts at 06:00 UT and ends at 12:06 UT. The umbral phase of the eclipse starts at 07:18 UT and ends at 10:47 UT. The maximum of the eclipse occurs at 09:03 UT with a magnitude of 0.978. The eclipse is visible in part from the United Kingdom. From Taunton, the partial eclipse starts at 06:00 UT and ends at 07:35 UT at moonset.
A total eclipse of the Sun occurs on Saturday December 4th 2021. It is visible as a partial eclipse from Antarctica, the South Atlantic Ocean, the southernmost part of South Africa, the South Indian Ocean, Tasmania and the southernmost part of Australia. The path of totality starts approximately 450km to the east of the Falkland Islands, crosses the Weddell Sea and the Ronne Ice Shelf, Ellsworth Land and ends over the Amundsen Sea, approximately 500km from the coast of western Antarctica. The eclipse starts at 05:29 UT and ends at 09:38 UT. The total phase of the eclipse starts at 07:00 UT and ends at 08:07 UT. The maximum duration of totality is 1m 57s at 07:33 UT over the Ronne Ice Shelf in western Antarctica. The eclipse is not visible from the United Kingdom.
Further information on all the eclipses in 2021 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, 2022, are also available.
Mercury returns to the evening twilight sky at the end of the first week of the month reaching greatest eastern elongation on Sunday January 24th. It moves higher in the west south-western sky as the month progresses making it visible low in the sky after the end of civil twilight. Mercury fades significantly from magnitude −1.0 at the start of the month to +0.7 by the end of January. It lies 1.5° south of Jupiter on Monday January 11th and 2.0° north of the waxing crescent Moon on Thursday January 14th.
Venus continues to move south in the sky as its elongation from the Sun decreases from 20° to 13° by the end of the month. It continues to lose its prominence in the south-eastern morning twilight sky, rising an hour or so before the Sun by the end of January. Venus remains at magnitude −3.9 during the month. It lies 1.5° north of the waning crescent moon on Monday January 11th.
Mars rises in the east north-eastern sky just before mid-day and sets a couple of hours after midnight in the west north-western sky. It spends the first five days of the month in the constellation of Pisces and then moves into Aries for the remainder of the month. Mars fades significantly from magnitude −0.2 at the start of the month to +0.4 by the end of January. It lies 5° north of the waxing gibbous moon on Thursday January 21st and 1.7° north of Uranus on Friday January 22nd.
Jupiter is visible in the west south-western early evening twilight until the middle of the month. It then becomes too close to the Sun for observation reaching conjunction with the Sun on Friday January 29th. Jupiter reappears in the morning twilight sky in the second week of February. It lies in the western part of the constellation of Capricornus for the whole of the month and remains at magnitude −1.9 for the whole of January. Jupiter lies 1.5° north of Mercury on Monday January 11th and 3.0° north of the waxing crescent Moon on Thursday January 14th.
Saturn is visible in the west south-western early evening twilight sky for the first week of the month. It then becomes too close to the Sun for observation reaching conjunction with the Sun on Sunday January 24th. Saturn reappears in the morning twilight sky in the second week of February. It lies in the westernmost part of the constellation of Capricornus for the whole of the month and remains at magnitude +0.6 for the whole of January.
Uranus rises in the east north-eastern sky before mid-day and sets around two hours after midnight in the west north-western sky. It is a blue-green object which fades slightly from magnitude +5.7 at the start of the month to +5.8 at the end of January. Uranus lies in the south-western part of the constellation of Aries where it remains for the rest of the year. It is approximately 8.7° north east of the fourth magnitude yellow giant star Torcular (ο Piscium). This planet can also be glimpsed with the naked eye under optimum conditions.
Neptune rises in the mid-morning in the eastern sky and sets in the mid-evening in the western sky. It lies in the north-eastern part of the constellation of Aquarius where it will remain for the rest of the year. Neptune is approximately 7.0° to the north east of the third magnitude red-giant star Hydor (λ Aquarii). It is a bluish object of magnitude +7.9 for the whole of the month. It can be visible with good binoculars under optimum conditions although it can also be difficult to distinguish Neptune from other stellar objects of a similar magnitude.
Pluto is too close to the Sun for observation until the beginning of February, reaching conjunction with the Sun on Thursday January 14th. It lies in the north-eastern part of the constellation of Sagittarius about 11.6° to the south west of Jupiter in mid-January. Strictly speaking, this is a dwarf planet which was demoted from the ranks of the 'bona-fide' planets at the 2006 International Astronomical Union General Assembly in Prague. At magnitude +14.7, you will need a much larger telescope to find this remote member of the Solar System.
The Quadrantid meteor shower is active from Monday December 28th 2020 to Tuesday January 12th 2021 although the shower reaches a very sharp peak of activity in the afternoon of Sunday January 3rd at around 14:30 GMT. The shower generates approximately 110 meteors per hour for around six to eight hours around the peak of activity. However, rates can vary between 60 and 200 meteors per hour. This shower is well known for producing fireballs and bright meteors usually lacking persistent trails. The peak of the shower this year occurs in the presence of a waning gibbous moon making for somewhat compromised conditions after midnight to observe this shower.
The radiant, the point from which the meteors appear to emanate, lies between the "tail" of Ursa Major, the head of Boötes, the Herdsman and the tail of Draco, the Dragon in the now-defunct constellation of Quadrans Muralis, the Mural Quadrant – hence the unusual name of the shower. The optimum time to observe the peak of this meteor shower in 2020 is to go out in the early hours of either Sunday January 3rd or Monday January 4th looking towards the north-eastern sky at an altitude of around 30°. The radiant gets higher as the night progresses reaching an altitude of 55° in the east north-eastern sky about 05:00 GMT.
These meteors are thought to be related to the asteroid 2003 EH1, an extinct comet which in turn may be related to a comet known as C/1490 Y1. This comet was first recorded by Chinese and Korean astronomers 500 years ago and probably disintegrated a century or so later. This makes the Quadrantids one of only two showers that are not connected directly with a comet – the other being the Geminids which were visible last month. No other showers exhibiting significant numbers of meteors are active this month. Further information can be found at the International Meteor Organization and their 2021 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.
C/2020 S3 (Erasmus) brightened rapidly shortly after its discovery on Thursday September 17th 2020. It reached perihelion on Saturday December 12th 2020 and starts the month at magnitude +8.1 fading to magnitude +11.0 by the end of the month. It starts the month in the constellation of Scutum and passes through Sagittarius Aquila Capricornus. Aquila again and ends the month in Aquarius. However, it is too close to the Sun to be observed this month as it lies within the twilight glare.
88P/HOWELL is a magnitude +9.9 object barely visible with a small telescope in the constellation of Aquarius where it spends the whole month. By the end of the month it will have faded by more than a magnitude. It can just be seen very low in the south-western sky in the early evening twilight. It reached perihelion on Saturday September 26th 2020 and is likely to be very difficult to find.
C/2020 R4 (ATLAS) is a magnitude +10.4 object barely visible with a small telescope in the constellation of Capricornus where it spends the whole month. By the end of the month it will have brightened by about a magnitude. It can just be seen very low in the south south-western sky in the evening twilight not too far away from the planet Mercury in the middle of the month. It reached perihelion on Saturday September 26th 2020 and is likely to be very difficult to find.
156P/Russell-LINEAR is visible in the constellation of Pisces during the first week of January and moves into the neighbouring constellation of Triangulum for the remainder of the month. It is a magnitude +10.4 object visible with a small telescope which fades by more than a magnitude by the end of January. The comet can be seen very high in the southern sky in the early evening setting a couple of hours after midnight in the western sky.
C/2020 M3 (ATLAS) is a magnitude +10.6 object best seen with a small telescope very high in the southern sky shortly before midnight but it is visible throughout the night. C/2020 M3 (ATLAS) was discovered on Saturday June 27th 2020 and reached perihelion on Sunday October 25th 2020. It reached its closest point to the Earth of 0.358au on Saturday November 14th. The comet spends the whole of the month in the constellation of Auriga, passing close to Capella (α Aurigae) at the beginning of January. By the end of the month it will have faded by as much as two magnitudes.
If you want to look for the International Space Station (ISS) as it passes over Taunton, please have a look at this page on the Heavens Above web site. 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 station, Tiangong-1, you are too late! Tiangong-1 re-entered the Earth's atmosphere in an 'uncontrolled manner' on Monday April 2nd 2018 at 00:16 UTC over an uninhabited part of the central Pacific Ocean at longitude 164.3° west and 13.6° south after the loss of a telemetry link in 2016. Information for Tiangong-2, the sole remaining Chinese space station orbiting the Earth, can be found on this page. Tiangong-2 is significantly fainter than the ISS, normally as bright as a third or fourth magnitude star. Predictions for other satellites may also be obtained from the Heavens Above web site.
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 might 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 press 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 Saturday January 16th 2021 from Taunton. The night sky will look the same an hour later at 23:00 GMT at the beginning of the month and an hour earlier at 20:00 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 Taunton for another date and/or time, please follow this link
In January 2021, the amount of daylight (measured from sunrise to sunset) increases from 8 hours 1 minutes at the start of the month to 9 hours 12 minutes at the end of the month. Total daylight (sunrise to sunset) for the month is 264 hours 11 minutes.
start and end times of civil, nautical and astronomical twilights.
|h m||h m||h m||h m||h m|
|** ** No phenomenon that day|
|PLEASE NOTE: These times are in Greenwich Mean Time (GMT) except between 01:00 GMT on March 28th and 01:00 GMT on October 31st when the times are in BST (British Summer Time) which is one hour in advance of GMT.|
The timings in the table above should be accurate to within 1–2 minutes inside the red circle superimposed on the map shown on the left.
Rising and setting times for the Sun, Moon and planets and times of twilights for other locations 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 between 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 in 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.