Sky watching will be very good in the islands in June. A trio of bright planets is visible in the evening sky, including Mars, which remains unusually bright throughout the month. Jupiter and Saturn are clearly visible from the midevening sky as well.
We have lost all of the winter constellations such as Orion and Taurus, but the classic starry patterns of summer, from Scorpius to the Summer Triangle, are now on parade.
Throughout this June, look for the distinctive triangle formed by Mars, Saturn and Antares, the brightest star in the Scorpion. While Mars’ brightness peaked in late May, it remains brilliant, and is by far the brightest member of the triangle. Orange-white Mars shines at minus 2 magnitude in early June and at minus 1.4 at the end of the month, still about as bright as the brightest star.
The other two dots in the triangle are the planet Saturn, the second brightest dot at zero magnitude, shining with its distinctive yellow-white color; and the star Antares, the least brilliant of the three dots at 1.03 magnitude, showing an orange glow that’s similar to much-brighter Mars. (Antares’ name means “the rival of Mars,” due to the similarity in color.)
Throughout the month the three dots make a long, narrow triangle; check out our June star map for their basic configuration. At the start of June, look for the trio rising in the southeast at dusk, with blazing Mars on top; Antares will be 12 degrees (a little more than the width of a fist) below Mars; and Saturn will be about three fingers to the left of Antares.
By midnight in early June the triangle will be halfway between the southern horizon and the top of the sky; by this time of night, the triangle will be on its side with Mars leading the way. By 4:30 a.m. in early June, the triangle plunges for the horizon in the west, Mars now the lowest dot and Saturn and Antares above.
Since stars and planets generally rise (and set) about 30 minutes earlier each week, things will look different at the end of June. By then, the triangle of Mars, Saturn and Antares will be high in the south as it gets dark at 8 p.m., with still-blazing Mars leading the way; the red planet remains the point of a narrow triangle, with dimmer Saturn and Antares each about the width of two palms to the left of Mars. The triangle hits the western horizon in the early hours of the morning in late June, with Mars plunging below the horizon at 2:30 a.m. and then Saturn and Antares taking the plunge around an hour later.
Look for the waxing gibbous moon (between first quarter phase and full phase) visiting the triangle on the nights of June 16-18.
On June 3, Saturn is in opposition. When an outer planet like Saturn is in opposition, this means there is a straight line between sun, earth and the planet. The ringed planet will rise at sunset, be overhead all night, set at dawn and shines at its brightest, at exactly zero magnitude.
For this May and June, we have the rare sight of Jupiter being rivaled in brightness by Mars. (Normally there is no contest here, Mars usually being the much fainter of the two dots.) At the start of June, look for Jupiter high in the southwest at dusk (two-thirds of the way between the horizon and the zenith), shining at minus 2.04; after you locate it in the west, compare its brightness to Mars, rising in the east. While white Jupiter is just a little brighter than minus 2 Mars, the distinctive orangey color of Mars stands out so much that the two planets look almost identical in brightness.
Jupiter sets in the west at 1 a.m. in early June. By month’s end, Jupiter is only about halfway up in the west at dusk, and sets around 11 p.m.
For the first half of June, Mercury rises in the east just after 4:30 a.m. and is about 10 degrees above the eastern horizon at daybreak. By June 15, it shines at minus 0.2 magnitude. For the week after that, until about June 22, Mercury comes up in the east around 5 a.m. and is visible for only about 20 minutes before being washed out by the day.
Southern Cross
In the islands, June is always the last time to find the Southern Cross, or Crux. After June, Crux vanishes into the sun, reappearing in the pre-dawn sky in December.
At dusk in early June (8 p.m.), look due south; the cross will be exactly south. When the Cross is due south, it is at its highest point, even though still quite low from Oahu. By dusk, the stars Alpha and Beta Centauri have also risen, and appear to the left of Crux. Find these two first; they are brighter than the stars in Crux and will pop out sooner. Once you’ve found these stars, go right, and they will point you to Gacrux, the top star in the Cross. By 10 p.m., the time the star map is good for in early June, Crux is still visible in the southwest but is heading for the horizon; the star map gives a good idea of what Crux and Alpha and Beta Centauri look like.
If you go Crux-hunting in the latter half of June, use our star map to locate the cross, low in the southwest. The map is good for 9 p.m. in mid-June, and right at 8 p.m. in late June. Make sure you have a flat southwest horizon, such as you get by looking over the ocean. As the Cross approaches the southwest horizon, it becomes even more important to use Alpha and Beta Centauri, the two “southern pointer” stars, to find your way to the cross. They are due south on the map.