The Night Sky This Month: November 2018

Asteroid 3 Juno
Image Credit: Atacama Large Millimetre/submillimeter Array (ALMA)

Prominent constellations at this time of year include Lyra, Cygnus, Andromeda, and Pegasus in the south, but the constellation Taurus is now appearing in east during the late evening. Taurus is known as one of the most beautiful constellations, and it includes two spectacular open clusters among its many deep sky treasures, namely the Pleiades (M45) and the Hyades.

The night of 16th/17th November also offers asteroid hunters the opportunity to view ‘3 Juno’ with binoculars in the constellation Eridanus as it moves towards its point of closest approach to the Earth. Observers can start tracking the 233 km-diameter asteroid from November 1st when it will shine at magnitude 7.58 at an elevation of 27 degrees, or a little above the star 35 Eridani, which will be shining at magnitude 5.2. By the 17th, the asteroid will be located to the lower right of the star 32 Eridani, where it will shine at magnitude 7.46.

Moon Phases

New Moon: 7th
First Quarter: 15th
Full Moon: 23rd
Last Quarter: 30th

The Planets

– Mercury will be furthest from the Sun on the 6th of the month, but since the ecliptic is at a very shallow angle relative to the horizon at this time, the little planet will be overshadowed by the glare of the Sun as it approaches a point of inferior conjunction. By the 27th, Mercury will have reached a point between Earth and the Sun, and will therefore not be visible during November.

– Venus will become visible as an early morning object on about the 6th, having passed between Earth and the Sun during the last week of October. Although Venus will be visible low on the eastern horizon at the start of November, the steep angle of the ecliptic at dawn means that the planet will gain height very rapidly as the month wears on. By month’s end, Venus will be visible at about 20 degrees above the horizon, but although its angular diameter reduces from 60.6 seconds of arc to 41.4 seconds of arc during the month, its illumination will increase from 1 percent to a spectacular 25 percent, which means its magnitude will increase from -4.6 to -4.9.

– Mars will dim from magnitude -0.6 to magnitude -0.1 during November, but since it rises from an elevation of about 17 degrees to about 27 degrees by month’s end, it will actually become more prominent in the sky as it clears the murk of the atmosphere as it moves into the constellation Aquarius. Although the Red planets’ angular diameter reduces to 9.3 seconds of arc from 11.9 seconds of arc it should still be possible to spot some surface detail on the planet with small to medium telescopes, due its higher elevation.

– Jupiter remains invisible during the month, since it is now approaching a point of superior conjunction with the Sun.

– Saturn can still be spotted at about 11 degrees or so above the southwestern horizon after sunset at the start of November, but it will become progressively more difficult to spot later in the month as it approaches the Sun. Nonetheless, look for Saturn just above the “Teapot” asterism in the constellation Sagittarius, where it will be shining at about magnitude +0.6 during the first half of the month.

– Uranus was in opposition on the 23rd of October, and it will therefore be visible throughout the night during November. It will culminate in the south at about 1 AM (BST) in the constellation Aries (near the Cetus/Pisces border), where its distinctive turquoise color should make an easy target for binoculars and small telescopes.

– Neptune was at its point of closest approach to Earth during the first week of September, meaning that it is still favorably placed for observation during November. The planet is now in the constellation Aquarius, and although it is still shining at magnitude +7.9 at an elevation of about 27 degrees, its angular diameter of just 3.7 seconds of arc means that telescopes 8-inch or bigger are required for the best views. Under clear and dark skies, larger instruments may be able to resolve Neptune’s moon Triton as well.

Meteor Showers

November sees two meteor showers, these being:

– The Leonids is expected to peak on the night of the 17th/18th of November, but sadly, the First Quarter moon will hamper viewing. However, meteor activity may be observed from the 15th to about the 20th, when up to 15 meteors per hour can be expected during this period.

– The Northern Taurids, which is expected to peak on the 10th of the month, is not a particularly productive shower and although it has a broad peak that runs for about 10 days, it rarely produces more than about 10 or so meteors per hour even at its height of activity. Nonetheless, this year there will be no moonlight during the peak and since the tail end of the debris stream is relatively rich in large particles, it may be possible to spot a few fireballs.

Deep-Sky Objects

Hyades and Pleiades

As mentioned, the constellation Taurus contains two beautiful open clusters among its many deep sky treasures. The image above shows both clusters in one field: to the lower left is the distinctive “V” shaped Hyades cluster, with the bright star Aldebaran marking out the “eye” of the Bull. Note though that Aldebaran is not a member of the Hyades cluster- it is less than half the distance of the Hyades proper from us, and its apparent position within the cluster is only the result of a fortuitous line-of- sight coincidence.

The blue open cluster to the upper right in this field is M45, the Pleiades, and it is arguably the most beautiful star cluster in the entire sky. Although the cluster is also known as the Seven Sisters, it contains about 3,000 stars all told and most share an almost identical composition, having formed out of the same molecular cloud. The ghostly blue glow is caused by starlight within the cluster being reflected off small carbon grains that make up a dust cloud through which the cluster was moving a few hundred years ago, and which we are only seeing now due to the cluster’s distance from us.

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