Venus is latest damp squib for astronomers

Such was the case on June 4 when observers all over Britain, with the exception of Shetland, were unable to witness the transit of our sister planet Venus across the face of the sun.

Its beauty – to paraphrase Shakespeare in Henry IV – was smothered up from the world by base, contagious clouds and there was nothing anyone could do about it.

One of the greatest disappointments for me was Comet Kohoutek way back in 1973.

It was spotted when over 400 million miles away, which implied that it was very large and predictions were that, by the time it crossed Earth’s orbit that December, it would be as bright as a first quarter moon with a tail streaming across the void like a cosmic peacock’s.

Designated in advance as the comet of the century, if not the millennium, its actual arrival was rather more prosaic.

Kohoutek turned out to be the dampest of damp squibs, barely visible to the naked eye and scarcely worth pointing one’s binoculars at.

The ancient peoples of the world often looked on comets as harbingers of dreadful events, including the wars, pestilences and plagues by which their lives were all too often shortened.

Could they present danger to modern humans and our fragile little planet?

Astrologers clearly believe they can, but astrologers will believe almost anything.

Are comets merely dirty snowballs careering harmlessly thorough the solar system and providing us with occasional spectacles in their own right or with meteor showers as an attractive by-product?

Over the next month or two I will try to take a balanced view.

In the meantime, those with an interest in the topic might care to look up Jan Hendrik Oort or even Ernst Opik.

The month in brief

The naked-eye planets:

Mercury – Just as Venus did last month, Mercury passes between us and the sun in July as it enters inferior conjunction. Regrettably, it won’t be on such a direct path that we will be able to see it against the sun’s face but, on the 28th, it will be passing through and, because it is so close to the dazzling light of our parent star, will be out of sight until August.

Its next transit will be on May 9, 2016, when – as with Venus last month – we will be able to see its disk against the sun. Weather permitting, that is!

Venus – Having transited the sun on June 4, Venus is now moving on to resume its position as the morning star but won’t be visible until very late in the month when it will come in view, in the south-east, shortly before and after sun-up.

Mars – Mars is low in the west after sunset but, given our extended twilight, will be very hard to see.

Jupiter – Jupiter, with its attendant moons, will be visible in the early hours of the morning in the south-eastern sky. On the 15th, for viewers in south-east of England, the king of the planets will be occulted by the moon. In other words, the moon will pass directly between the viewer and it. We are too far north to enjoy this but may be able to see a very close pairing between the two objects.

Saturn – Saturn is very low in the western sky after sunset and will be setting quite soon after the sun so will not be a good target for observation.

Noctilucent clouds:

The chances of seeing noctilucent cloud remain very high throughout July provided that the lower clouds – to which we are more accustomed – clear sufficiently for us to have a view of the atmosphere beyond.

These ethereal phenomena were the subject of a recent excellent talk in the Castlehill centre by Ken Kennedy, of the British Astronomical Association. But, in spite of his revelation of their increasing frequency and wider distribution, we haven’t seen a lot of them since. Maybe July will be the month for noctilucence.

Phases of the moon:

Full moon – Tuesday, July 3, at 18.52.

Last quarter – Wednesday, July 11, at 01.48.

New moon – Thursday, July 19, at 04.24.

First quarter – Thursday, July 26, at 08.56.

Jim A. Johnston would welcome suggestions for future topics for his Skywatching column. He may be contacted by e-mail at jimajo@btinternet.com

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