In
the evening sky, low in the horizon, if we carefully look we can find
the smallest planet in our solar system. After sunset, in a place
where there are no obstruction like buildings or trees, in this
unobstructed view of the western horizon we can spot planet mercury.
Since mercury orbits close to the sun we can only find the planets
close to the horizon in evening or morning skies.
During
its orbit around the sun there are two favorable points where we can
observe the planet. This is the maximum separation of angle between
Sun and planet. This point of maximum separation is called Greatest
elongation. For planet mercury this greatest elongation angle is
between 18 degrees to 28 degrees. This is the reason why most people
miss the planet, since it is so close to horizon.
On
November 6th the planet will reach greatest elongation
giving us a good opportunity to catch a glimpse of this planet with
naked eye, binoculars and telescopes. The angle for this elongation
is 23 degrees, this means just after sunset the planet will be
23degrees above western horizon.
 |
| Spot planet after sunset in western sky. |
The
planet will be at a magnitude of -0.2, although it is bright the
drawback is that it is immersed in twilight making it difficult to
spot but as twilight fades its easy to spot.
With
a telescope we can see the gibbous phase of mercury with an angular
size of 6min of arc. The planet will be in half phase on 11th
of November and from there on the illuminated side of mercury will
start decreasing. This is a nice time to see and enjoy and also
understand the phases and orbit of mercury. Since the planet is
coming closer to earth the angular size will keep increasing and it
will be 9mins of arc before the planet sinks into the glare of the
sun and then reach inferior conjunction on 27th of
November.
Clear
Skies.
