The night sky in March 2018

posted 28 Feb 2018, 01:52 by Pete Collins
by Anne Holt

Sunrise        1st:   06.57       31st:    06.45  (BST)
Sunset         1st:   17.46       31st:    19.42    "

Astronomical darkness 
 1st:   19.12 -  04.58      31st:  21.47 - 04.37  "  

British Summer time begins on Sunday 25th at 01.00, when the clocks go forward one hour.
The Vernal Equinox. when the centre of the Sun's disc crosses the plane of the celestial equator, is on 20th at 16.15.  Despite the name, day and night are not equal then - the day is 12hrs 10 mins 19 seconds long.   The closest day to 12 hours is 18th at 12h.01m.46s. 

Full Moon:    2nd at 00.51  and  31st at 13.36
New Moon:   17th at 13.11

The full Moon on 2nd is known as the Worm Moon because it is when the ground begins to soften after the Winter frosts and worms reappear.  (but maybe not this year).  It is sometimes known as the Lenten Moon - for obvious reasons.
The second one is, of course, another Blue Moon - but just a regular one this time.

Highlights

Again, not a lot in the way of things to look forward to.  Planetary positions are improving slightly, with Jupiter rising earlier and Venus setting later, but neither has yet reached its best for the year.  The Moon passes through the Hyades on 22nd, occulting several of the stars.  It passes in front of Aldebaran soon after 23.30 but they will be very low in the sky by this time.
What we really need to do this month is to appreciate the things we'll soon have  to say goodbye to until next Autumn, so enjoy them while you can.   Orion, the most beautiful constellation in the sky is setting soon after 11pm by the end of March, we have less astronomical darkness: fewer than 7 hours at month end,  BST is imposed on us from 25th and, worst of all, our last meeting of the season is on 29th.

Constellations

We are now losing the winter highlights of Orion, Sirius and Taurus soon after midnight, though they are still promiinent in the south in the early part of the night.
Auriga, with the bright yellowish-white star Capella, is now overhead soon after sunset, with Gemini and Leo also prominent. The not very obvious zodiac constellation, Cancer, is now well placed. The Plough is overhead by midnight, the handle pointing to the orange hued Arcturus, the brightest star north of the celestial equator, in the constellation of Bootes. By the end of March the Summer Triangle will be above the horizon soon after 2am - or by 1am if you've forgotten to put the clock forward.
 
Planets

Not the best time for planetary observation, all the naked eye planets are very low in the sky, even at their highest point.

Mercury:  in Aquarius, mag  -1.3. Not visible in the first few days of the month,  on 1st it sets about 80 minutes after the Sun but is only 6 degrees above the horizon as the sky darkens.  On 3rd it moves into Pisces and a few days later may be glimpsed briefly soon after Sunset.  On 6th it will be at an altitude of 8 degrees at 18.00.  The following couple of weeks is the best time this year to see it, it will be higher in the sky as darkness falls - 12 degrees on 13th - but will have faded to mag -0.7.  It reaches Greatest Eastern Elongation on 15th, when it sets 1hr 45 minutes after the Sun, but is down to mag -0.4.  It fades rapidly during the rest of the month, mag 0.3 on 19th and 1.1 on 22nd, when it will be very low in the West at dusk.  It won't be visible by month end as it appears only 4 degrees from the Sun and will have faded to mag 5.3.

Venus:  in Aquarius, mag 3.9. Appears close to Mercury in the early evening sky for much of March.  On 1st it sets at 18.46 about an hour after the Sun but will be only 6 degrees above the horizon at dusk.  It moves into Pisces on 3rd, when it appears only one degree left of the much fainter planet, neither easy to see as they are very low in the darkening sky.  Venus sets 3 or 4 minutes later each night and, after the first few days of March, should be more easily visible, low in the West at dusk. It spends a couple of days (13 & 14th) in the non Zodiac constellation of Cetus the whale before moving back into Pisces for the rest of the month.  On 18th, Venus, Mercury and the 1% lit Moon will appear in a straight line about 30 minutes after Sunset, with Venus in the middle at an altitude of 10%, Mercury slightly higher and the Moon very low.  By the last week of the month Venus is still getting higher in the evening sky, leaving Mercury behind. On 31st it is 12 degrees above the horizon at dusk and sets at 21.28.

Mars:  in Ophiuchus, mag 0.8. On 1st it rises at 03.03 and reaches its highest point at 06.49.  Because of its relatively fast Eastward movement it rises less than a minute earlier each day.  Moves into Sagittarius on 12th.  It is now getting closer to Earth so during the month will brighten, and the disc will appear to be increasing in size when seen through a scope.  However, the downside is that it remains very low in the sky, no higher than 11 degrees throughout March.  On 31st, when it will be at mag 0.3, it rises at 03.26 and culminates after Sunrise.

Jupiter:  in Libra, mag -2.2. Rises at 00.32 on 1st, and reaches its highest point, 19 degrees above the S horizon, just before 5am - as astronomical darkness ends.  It rises 3 or 4 minutes earlier each day,  before midnight after the first week of the month.  Like Mars it appears to increase in size during March, and also brightens slightly.  It ends the month at mag -2.4, rising at 23.36 and culminating at 03.56.

Saturn:  in Sagittarius, mag 0.6. Visible low in the pre dawn SE sky, a little to the North of the teapot asterism.  Rises at 04.14 on 1st but is best seen after 11th, when it will be 11 degrees above above the horizon as dawn breaks.  On this day it is just 2 degrees from the 34% lit Moon.  At month end it rises at 03.22 and will be at mag 0.5.  During the month the slightly brighter and much more reddish hued Mars appears to be moving towards Saturn, on 31 st they will be separated by only 1.5 degrees.

Uranus:  in Pisces, mag 5.3. On 1st it is 24 degrees above the Western horizon as the sky darkens, setting a few minutes after 22.00.  Sets a few minutes earlier each day and is soon lost in the evening twilight.  On 28th it is only a quarter of a degree from Venus but too faint to be seen with the unaided eye.  Might be visible in binoculars but DO NOT point binoculars or a scope at Venus until the Sun is fully below the horizon.

Dwarf Planets
Makemake is at opposition on 24th but at a mag of only 17 won't be visible in most amateur scopes.  Could be a possible photographic target as it passes through Coma Berenices in a NW direction.
At mag 7.6 Ceres, in Cancer, is a much better bet for telescopic observation.  On 1st it culminates at 22.23, about 68 degrees above the S horizon.  On 31st it culminates at 21.16.  

For more information on the position of planets, dwarf planets and other Solar system objects see  https://in-the-sky.org/ephemeris.php  or https://theskylive.com

Meteors

Another bad month for meteor spotters in the Northern hemisphere.  If you do happen to be South of the equator there is the Gamma Normids which peak on 16th with a ZHR of 6.
From our latitudes the best we can expect is several small showers with radiants in Virgo - the pi Virginids (peak between 3rd & 9th), eta Virginids (peak 18th) and the theta Virginids (peak 20th), all with a ZHR of 3 or less.  The International Meteor Organisation now classes these as part of the antihelion source as the radiants are very close and the showers almost impossible to separate.

Comets

There are still several faint comets around but none are brighter than mag 10.5.  For anyone who wants to try their hand at photographing these, more details can be found in www.cometwatch.co.uk/current-observable-comets/
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