Four planets light up the night sky

In May and June, Mercury, Mars, Jupiter and Saturn can be seen falling in line forming a natural planetary conjunction, writes S A Mohan Krishna.

Planet watching is one of the most fascinating, enjoyable and mesmerising activites.

If we witness the sky on a dark, clear night we can see hundreds of stars and few terrestrial planets also.

They are not alike; they are of different colours, and of course they differ in brightness.

Planets move slowly among the stars, following patterns that repeat over months or years.

In May, Indians are privileged to witness four planets in the night sky namely Mercury, Mars, Jupiter and Saturn falling in line forming a natural planetary conjunction.

It is a fabulous astronomical spectacle for amateur astronomers and general public.

The innermost planet of the solar system is Mercury.

Its orbit keeps close to the Sun hence the planet is visible only shortly before or briefly after sunset.

It is clearly perceptible as a magnitude star at approximately two-monthly intervals.
Skywatch

During times of best visibility, Mercury stands low in the twilight for about three weeks.

It looks like a warm-white star and binoculars often help us to spot it.

Presently, it can be seen at around 6:30 PM (IST) after sunset and is regarded as a hostile planet.

It is well placed for viewing over the western horizon after sunset for northern hemisphere observing.

Very occasionally, the Earth, Mercury and the Sun accomplish planetary conjunction and the planet is then seen as a small dark spot crossing the yellow solar disc.

Mars is the resplendent yellow-orange planet in the solar system.

Mars reached opposition on April 8, 2014 and the best visibility happens every 780 days on average.

The magnitude of Mars decreases from -1.5 at the beginning of the month to about half of that, -0.60 by month’s end.

Look for Mars high over the southeast horizon at sunset, and it sets just a few hours before sunrise.

During night, we can clearly see the red planet at around 7:00 PM (IST) over the southeast or almost in western horizon.

Mars can appear at any place in the sky on the ecliptic, rather than always staying near the Sun, like Mercury and Venus.

On first viewing Mars by telescope, beginners are often startled by its smallness.

Even at its closest approach. Mars appears no larger than a lunar crater.

Typical first looks show an amber disk, some faint markings, and maybe a whitish polar cap.

Jupiter is the fifth planet from the Sun and the largest of the Solar System, easily perceptible with the unaided eye.

Jupiter can be seen around 6:45 pm (IST) over the southwest horizon at the beginning of the month, and quickly becomes a bright and noticeable evening planet.

It can be seen in the constellation Aries.

Jupiter’s disk offers the backyard astronomer a wealth of ever changing detail that can be seen in almost any telescope.

Bright zones and dark belts vary in strength and change position slightly.

Jupiter’s most famous single feature is the Great Red Spot, a vast and turbulent eddy located just below the south equatorial belt that has been observed for at least 300 years.

A treat for the eyes

Saturn is the sixth planet from the Sun and the outermost planet immaculately perceptible with the unaided eye.

The imperative physical distinctiveness like magnitude, composition, internal configuration, and atmosphere advocate an overall similarity to Jupiter.

Saturn’s rings are well known and were explored in great detail by the Voyager missions.

Saturn rises at about 6.30 pm (IST) and will be visible throughout the evening sky and over the western horizon during night sky.

Almost any telescope will show Titan, Saturn’s largest moon, and at least three other moons will be apparent in a 6 inch telescope.

To see Saturn’s low-contrast cloud features better, try using a blue filter or view during mid-twilight.

The term conjunction primarily refers to a phenomenon defined only for the position of the observer, not just to a celestial relationship.

However, for moon and Sun observed from the earth, conjunction as a classifying term may apply both to the positions of conjunction (both sun and moon observed jointly in one direction or with similar elliptically longitude) and to opposition (both sun and moon observed separately in opposite directions or with elliptically longitude 180 degrees apart).

As seen from a planet that is superior, if an inferior planet is on the opposite side of the Sun, it is in superior conjunction with the Sun.

An inferior conjunction occurs when the two planets lie in a line on the same side of the Sun.

In an inferior conjunction, the superior planet is “in opposition” to the Sun as seen from the inferior planet.

The terms are generally used with respect to Venus and Mars as they are the inferior planets when seen from Earth.

Enjoy watching these dominating planets in May and June. These planets can be seen through naked eyes easily.

Telescopes for planet watching need sturdy mountings and high-quality optics.

Most observers use powers of 200x or less, due to unsettled view.

Also useful are coloured filters, which accentuate specific features on planets.