Sky Notes March 19 turn

PULSAR
NORTH ESSEX ASTRONOMICAL SOCIETY
March 2019
SKY NOTES
Special edition

Image credit: NASA

March 2019
The Spring Equinox arrives on March 20th and around this date daylight expands at its fastest
for the year – increasing by about 4 minutes each day. The clocks go forward to British Summer
Time on Sunday 31st March when at 1 am the clocks go to 2 am and we then stay on BST
until late October. So on April 1st sunset is at 7.30 pm BST and twilight will last until 9.30
pm BST.
Full Moon this month is in the early hours of the 21st. Our nearest neighbour in space will
then be in the constellation of Virgo and some 20 degrees lower in the sky when in the South
compared to a mid-winter Full Moon.
This month marks the 50th anniversary of the Apollo 9 mission. NASA was under pressure
as the 1960’s drew to a close to achieve the goal set by JFK in 1962 of landing on the Moon
before the end of the decade. It was a period of only months between Apollo 8 being the first
crewed spacecraft to leave Earth orbit at the end of 1968, to the successful landing on the Moon
by Apollo 11 in July 1969.
But between these achievements NASA had to test the equipment and methods that would be
needed for the landing. Apollo 9 was a “low key”, but vital Earth-orbiting mission that lasted
10 days and was used to test the Apollo lunar module for the first time.
Mars is still an evening object setting at about 11 pm by the end of the month. It is by then
mag +1.4 and with a disk under 5 arcseconds in diameter. The young crescent Moon will be
close by on the evening of March 11th. This early Spring period is an ideal time to see if
Earthshine is visible on the part of the young Moon not lit by the Sun.
Jupiter remains an early morning object and will be very close to the last quarter Moon on the
morning of the 27th, best seen in the South at 5 am, or just before.
Comet 2018 Y1 (Iwamoto) passed 0.3 AU from the Earth on February 12th and was an easy
object in large binoculars. It fades through March but remains an evening object in the West
– as ever the BAA Comet Section has details on all currently observable comets.
Before the Moon waxes towards Full, late evenings during the second week of March will be
a good time in dark skies to view galaxies. The Virgo cluster will be well placed at this time
– located high in the “bowl” of Virgo and swarming around the giant elliptical galaxy M87.
Everything about M87 is big. It is home to several trillion stars, a relativistic jet being powered

y the central super-massive black hole and a family of roughly 15,000 globular clusters –
compared to the 157 globular clusters associated with the Milky Way.
The Virgo Cluster is the closest and best-studied great cluster of galaxies, at a distance of
approximately 50 to 70 million light years. It is the nucleus of the Local Supercluster of
galaxies, in whose outskirts we in the Milky Way and the Local Group are situated – and
gravitationally associated. 15 of the 109 Messier objects are Virgo Cluster galaxies.
In the first week or so of March the full array of Winter constellations are still well placed in
the evening, though not for much longer as we head into Spring. At 9 pm, Sirius is in the South
and above it and a bit to the left is Procyon. Both stars are bright as we see them and, in
astronomical terms, in “our neighbourhood”, Sirius being only 9 light years away and Procyon
11 light years distant. To the right of Procyon the imposing outline of the constellation Orion
has all of its primary stars much further away from us. Notably, Rigel, whilst it appears only
slightly brighter than Procyon, is in fact over 700 light years away, shining with a luminosity
around 80,000 times greater than our Sun. If Rigel were the same distance from us as Procyon,
it would be as bright as a first quarter Moon and casting shadows at night.
James Abbott
Picture: M87 - credit The Hubble Heritage Team