The M.A.S. Newsletter
Journal of the Mauritius Astronomical Society
February 2000
The Next Meeting:
The annual general meeting, will be due on Friday 25th of February 2000 at 7:30 pm at the Saint Esprit College, Quatre Bornes.
AGENDA:
Reading and approval of
previous AGM minutes.
Matters araising.
President's address.
Treasurer's report.
Committee members for 2000.
A.O.B.
NOTE:
Members wishing to from part of the committee should send their letters to reach the Secretary not later than Wednesday the 23rd of February. We hope to see you for this important meeting.
MY ADDRESS:
Serge Florens
47, Rue Vengta
Solférino
MAURITIUS
The sky this month:
A very crescent Moon passes close to the planet Mars after sunset on the 8th. On the night of the 10th and 11th, the Moon visits Jupiter and Saturn. On the 12th, Mars, which sets at 20:47, is virtually at the Vernal Equinox, observable just after sunset. Mercury returns very briefly to the evening sky where it is observable till the 23rd of February. It is now in the constellation of Aquarius, entering Pisces on the 19th, and by the 23rd vanishes back in the glow of dusk.
The Zodiacal Light:
The zodiacal light is a skyglow which
is visible in the plane of the zodiacal constellations. It is the sunlight scattered off a
limitless number of small particles a few micrometers in size, each of which is orbiting
the Sun indepedently. The high density of the dusts near the Sun results in the zodiacal
light being visible shortly after the end of evening twilight to the west and before the
morning twilight to the east as what is more accurately called the zodiacal light
pyramids. Also part of the display, the gegenschein, the German word for
counterglow, can sometimes be seen centered at 180º from the Sun as an oval patch of
light about 15º across. The gegenschein and the zodiacal light pyramids are
joined by the extremely faint zodiacal band. The zodiacal light pyramids can
be seen all year round from the seaside on a dark moonless night whereas the gegenschein
can only be observed on a dark moonless sky when the Milky Way does not happen to be
in the background i.e. in the months of February to April and September to November.
Gegenschein Visually Observed:
The perfect instrument to view the gegenschein is a large (15cm) diameter tube blackened on the inside. All the beginning of the month of February, the tube (which works like a horse's blinders) must be directed close to y Leonis, midway between Regulus and M44 Praesepe. Whereas at the end of the month towards r Leonis (rho of the Lion). In November, towards d Arietis (delta of the Aries), about 10º to the west of the Pleiades. The time of observation should be around midnight when the gegenschein is highest in the sky.
Serge Florens, Secretary