Webmaster © Paul L Money 2010
Occultation’s of Stars and Planets by the Moon
During its orbit the Moon can pass very close to some of the brighter stars and bright planets often producing a conjunction which is enjoyable to see. Occasionally though it gets even better when it actually occults (covers) the object. 2010 has several opportunities involving the moon and stars but sadly there are no bright planets occulted this year. Although some of them will be challenging in twilight or almost full moonlight they are worth trying for either with binoculars or a small telescope if you have one. In Nightscenes as a rule I always select stars brighter than magnitude 4 so that everyone stands a chance of spotting them and potentially seeing the event. Note that all times given are approximations, always begin observing at least ten minutes before the start. Note that all the tracks are now shown for the two extremes of the occultation path across the UK and Ireland. The northern limit is set for the top of mainland Scotland whilst the southern limits are set for Southern England and Ireland. The rest of Great Britain and Ireland falls between them. D = Disappearance and R = Reappearance. By a strange quirk all the main events for 2010 occur in the early hours of the morning but that's the nature of astronomy!
Occultations for the rest of 2010
On May 28th the occultation is a challenge as it involves a Full Moon. It is included
as the star, Sigma Scorpii or Al Niyat is bright at mag 2.9 and so it should be visible.
Full Moon only occurs three hours earlier so there will be little in the way of a
dark limb but the author is always fascinated to watch the moon slowly creep up towards
the stars as it shows the solar system in motion! Start viewing from about 02:05am
(BST) for the difficult disappearance and begin looking out for the difficult reappearance
from about 03:00am! The moon will be low in the SW during this event and the bright
star off to their left is Antares -
The final occultation has to wait several months until October 28th but again lies
in the early morning sky. It involves mag 2.9 Mu Geminorium also called Tejat Posterior
which is quite high in the south part of the sky. 'D' is at the bright limb and you
should begin checking its progress from about 05:50am (BST). The further south you
are then the closer to the Moon's southern limb is where you will see the star disappear
and it will be occulted for a shorter duration. Somewhere like Inverness will see
'D' at approx 05:54am whereas Plymouth will see 'D' at around 06:18am. For Inverness
the duration will be at least 59 minutes (R= ~06:54am) whilst Plymouth will have
around 27 minutes (R= ~06:45) before the star reappears. 'R' is at the dark limb
so should be quite spectacular when Tejat suddenly reappears. It can often catch
even the most experienced observers out. This is due to the fact the Moon has no
atmosphere and so there is no dimming of the starlight -