The nights of June are not very long as we march towards and past the “longest day” where 16 hours of sunlight actually mean 20 hours of daylight for us living in temperate zones. Nevertheless, there are some great objects to look out for, especially the planet Saturn.
Moon in June:
New: 24th June
First quarter: 1st June
Full: 9th June
Last Quarter: 17th June
Planets in June:
Mercury: Moves into Taurus in June and is not well placed, coming to superior conjunction on the 21st of the month.
Venus: is a morning object rising before the Sun in the constellation of Aries and is still a brilliant object. It is at greatest western elongation on the 3rd June.
Mars: Is in Gemini at mid month and sets by 19:00 so is not well placed for observation in the bright daylight.
Jupiter: still shines as a bright object in the constellation of Virgo, lying close to the first magnitude star Spica. Shining at magnitude -2 the planet is still visible most of the night.
Saturn: rises in Ophiuchus after sunset but the lighter evenings may make it an object for later study. It is at opposition on the 15th June and can be seen all night, shining at magnitude 0. The rings look fantastic!
Uranus: Is in Pisces and shines in the early morning rising at 02:00, shining at magnitude 5.9 but only subtends a small disk just under 4” across.
Neptune: The furthest planet from the Sun remains in Aquarius and rises just before midnight but shining at a miserable magnitude of 7.9. It has a small 2” disc.
Meteor showers in June.
June has a lack of meteor showers worth looking out for. Due to the twilight lasting into the late and early hours any meteors would have to be very bright to be visible. However, there are some under reported showers such as the Arietids, which have a long period of activity between the 21st May and the 2nd July, which may be associated with the minor body 1566 Icarus.
There are also the June Scutids which are active between the 2nd June and the 29th July and the June Lyrids active between the 11th – 21st June. The ZHR for all these showers is very variable and so any meteor seen in the late evening or early morning during these dates could belong to any of the above showers.
Interesting Events in June
On the morning of 2nd June the two planets Uranus and Venus are separated by only 1.8 degrees and so may present an interesting photo opportunity. Look out for the waxing and waning moon moving close to any of the planets throughout the month, especially on the 3rd June when the 9 day moon will be close to Jupiter in the constellation of Virgo.
Comets in June
Comet C2015/V2 Johnson continues to be a lovely object for binocular observation throughout the month as it passes the star Izar in Bootes in the first few days of the month and travels through Bootes for most of June. The comet is expected to reach perihelion in June but it will still be well placed throughout the early parts of the month. In June, the comet may reach magnitude 6 before it plummets southward, becoming unobservable to northern sky observers by July. The finder charts can be found here:
Constellation of the Month: Corona Borealis
The constellation of the “Northern Crown” is easily recognizable on a spring evening, sandwiched as it is between Bootes and Hercules. It is an ancient constellation said to represent the crown given by Theseus to Ariadne after his defeat of the half man – half bull creature, the Minotaur. Theseus later deserted Ariadne, and she threw away the crown, only to have the gods place the emblem in the sky. It has been used as a pastoral sign, as the Greeks under the scholar Eratosthenes connected it with the laurel wreath. Its agricultural significance is evident as the poet Virgil attests:
If thou plow to sow more solid grain,
A Wheat or Barley harvest to obtain,
First let the morning Pleiads set,
And Ariadne’s shining coronet,
Ere now commit the seed to the ground.
In Welsh mythology this constellation is associated with the Goddess Arianrhod. This charming little circlet of stars holds a few deep sky wonders that are well worth the trouble to find, although major deep sky objects such as clusters or nebulae are sadly deficient.
The main attraction of Corona Borealis is without question the variable star R. Corona Borealis, but this is a variable with a difference as R Coronae usually stays at maximum light, around 6th magnitude, before fading away, sometimes down to 13th magnitude. R Coronae is a late type M or R type object that has intense lines of carbon in its spectrum. As such giant stars give out large stellar winds, what probably happens is that R Coronae is cutting itself off from the rest of the universe by hiding behind vast clouds of “soot” that condense out as the material of the stellar wind cools and becomes grainy.
The light fluctuations are irregular in period; no one in fact can predict when R. Coronae is going to disappear, so it is worth keeping an eye on it whenever it is visible. R coronae is the prototype of this kind of variable, and is a halo object, a population 2 star lying between 2500 and 4000 light years away, the discrepancy in the computed distance lying in the fact that different observations of the star have revealed different spectral peculiarities that give rise to opposing computed distances. Whatever the case, R coronae is the most attractive and wondrous star of its type and can be easily seen with binoculars or a small telescope.
a Coronae or “Gemma” is a double star that unfortunately can only be split with a spectroscope, but close by this star is a field of faint stars that contains the only well observed recurrent novae. The star is T. Coronae, and it appears to go through novae – like eruptions every 80 to 100 years or so, the last occasion was in 1946. This period is by no means fixed however, so scan the field and identify this 10th magnitude star so that you can observe it regularly.
The star r Coronae has an attendant planetary system, which was discovered in 1997. The planet is another massive Jupiter and is extremely close to the parent star, only 0.23 AU from the star and having a mass of 1.5 times that of Jupiter, revolving around the star in 40 days. The orbit is so close that the atmosphere of this planet is estimated to be in excess of 300 degrees and may be blowing off into space with the impact of the stellar wind from the star.
There are few other objects that will draw the attention of the average amateur in this stellar group. In the southwest corner of the constellation there is a rich field of galaxies arising from the presence of the Corona Borealis cluster, but these objects are over 150 million light years away and the brightest of them is beyond the reach of most amateur equipment.