In the Transient Sky – June 2012

The big event this month (at least for folks around the northern Pacific basin) is the annular solar eclipse on May 20. As for planets, Venus, Mars and Saturn are easy to see in the evening.

June 2012 Highlights
* Transit of Venus on June 5
* Partial Lunar Eclipse on June 3 
* Venus rockets out into the morning sky
* Mars fades but still is high in the evening sky
* Saturn is easily seen in eastern evening sky
* Mercury starts a nice apparition in the evening sky

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <>.

Partial Lunar Eclipse

The Moon follows up last month’s annular eclipse with a partial eclipse on the morning of June 4th. The eclipse can be seen  North and South America, Australia, eastern parts of Asia and all across the Pacific Ocean. Only 37% of the Moon will enter the umbra so it will be far from a total eclipse. Here in the US, the Moon enters the dark umbra at 10:00 UT (6:00 am EDT, 5:00 am CDT, 4:00 am MDT, 3:00 am PDT). Maximum eclipse occurs an hour and three minutes later. For more information on when and where this event can be seen go to Science News @ NASA Science.

Venus Transit of the Sun

On June 5th, Venus will pass in front of the Sun for the first time since 2004 and the last time till 2117. For more info please visit the Transit of Venus website.


Evening Planets

Mars – Mars is the brightish reddish “star” to the SW early in the evening. Mars reached opposition (the point opposite the Sun on the sky) in early March. In June, it fades from +0.5 to +1.0. The red planet will spend the month moving eastwards from the constellation of Leo into Virgo. The Moon visits on the evening of the 25th and 26th.

Saturn – Saturn reached opposition on April 15 at a distance of 8.75 AU (813 million miles or 1.3 million km) from Earth. This month it continues making a nice but distant pair with the bright 1st magnitude Spica. Both can be seen to the South at the end of twilight. Saturn will fade from magnitude +0.5 to +0.7. The Moon visits on the mornings of the 27th.

Morning Planets

Mercury – This month Mercury starts a rather good apparition for northern observers in the evening. It reaches its highest point above the horizon on June 22.

Jupiter – A month past conjunction with the Sun, Jupiter can be seen slowly rising out of morning twilight. During the later half of the month Jupiter and Venus make a nice pair once again (similar to their showing this Spring in the evening) against the backdrop of the Pleiades and Hyades clusters of Taurus. The Moon is located near Jupiter on the morning of the 17th.

Venus  – After its spectacular transit of the Sun on the 5th Venus enters the morning sky. Not quite reaching as high as Jupiter, the brightest planet will be easy to see just before the start of morning twilight by the end of the month. The Moon pays it a visit on the morning of the 18th.


The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers. Background rates start to tic upwards in June.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During June mornings, 7 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None this month

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the International Meteor Organization’s 2012 Meteor Shower Calendar.


Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)


Small Telescope Comets (V = 8.0 – 10.0)

Comet 96P/Machholz

Comet 96P/Machholz is the only comet that may be brighter than 10th magnitude this month. And even then it will only be brighter than 10th magnitude for the last day or two of the month. Next month the comet will be much brighter though it will also be located closer to the Sun.

This comet has one of the smallest perihelion distances of any short-period comet at 0.12 AU. For this go-around, the comet will reach perihelion on July 14. During June it will only be visible from the Southern Hemisphere. Northerners will get their chance towards the end of July. At the start of June, it will be located 1.19 AU from the Sun and 1.17 AU from Earth. Though rapidly brightening it will still only be a faint magnitude 14. By the end of the month the comet will have brightened to magnitude 10 or a little brighter. It will close out the month at a distance of 0.55 AU from the Sun and 0.95 AU from Earth.

Don Machholz first spotted 96P back on May 12, 1986 at magnitude 9.7. Though the comet can get very bright (up to magnitude -2) it is always located too close to the Sun for observation when that bright. By the time the comet has moved far enough from the Sun for easy observations it will have faded to 8th or 9th magnitude. It currently takes ~5.3 years to orbit the Sun.

Date            RA        DEC    Delta   r   Elong    V
2012 Jun 01   01h 59m  -31d 44'  1.168 1.190   66   14.2
2012 Jun 10   02h 58m  -26d 41'  1.031 1.015   59   13.1
2012 Jun 20   04h 12m  -17d 24'  0.942 0.798   48   11.7
2012 Jun 30   05h 27m  -04d 13'  0.949 0.549   32    9.8

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude