Night Sky Highlights for April-June, 2015
Solar System
Mercury
Mercury makes its best appearance of the year along the western horizon after sunset in late April and early May. On April 30, it will be just a few degrees away from the Pleiades.
Venus
Bright Venus will be visible in the western sky after sunset throughout the spring, and by June a view through a telescope or large binoculars should show a half-illuminated ball, like a miniature version of the first-quarter moon.
Mars
In early April, Mars will be low in the west just after sunset, but soon it drifts too close to the Sun and out of sight for the rest of the spring.
Jupiter
Throughout the spring, Jupiter will be high in the sky during the evening hours, not too far from the Beehive Cluster in Cancer. On June 30, it will pass within 1/3 of a degree of Venus, which should be a very impressive conjunction.
Saturn
The ringed planet is currently located just a bit to the west of Beta Scorpii, the northernmost of the 3 stars that form the “claws” of the scorpion. It rises around midnight in April, but by June it is visible in the east as soon as the evening sky darkens.
Lyrid Meteor Shower
April 22-23, late evening until dawn
This first meteor shower of the spring season is not particularly strong. Its zenithal hourly rate (ZHR, the estimated maximum rate under ideal conditions) is about 15-20 meteors per hour. But with the Moon out of the sky by later in the evening, this is a good year to try to observe them.
Deep Sky Objects
The spring season is known for the many galaxies that can be observed in the regions of Leo, Virgo, and Coma Berenices with a telescope of modest size. There are, however, many other types of deep-sky objects overhead, just waiting to be observed.
Messier 44, the Beehive Cluster
Open cluster in Cancer
Dimly visible to the naked eye from a dark site, this is good binocular target. Compared to the Coma Berenices open cluster (see below), this group is much smaller—about 1.5 degrees in diameter.
Melotte 111
Naked-eye open cluster in Coma Berenices
This is one of the nearest open clusters, at a distance of about 260 light years. This cluster spans over 5 degrees of sky. Its brightest stars are about magnitude 4 and 5, making them visible under a reasonably dark sky.
Messier 53 and NGC 5053
Two globular clusters in Coma Berenices
Messier 53 is located 1 degree to the northeast of alpha Coma Berenices, the brightest star of this dim constellation. It is a fairly bright globular cluster with stars that can be resolved in a medium-sized telescope. NGC 5053 is a smaller globular cluster just 1 degree ESE of Messier 53.
Messier 65 and 66, and NGC 3628
Three galaxies in Leo
Known as the Leo Trio, these three bright spiral galaxies form a triangle about 1/2 degree wide, so they can easily fit in the same field of view with a low-power eyepiece.
Messier 84 and 86
Two galaxies in Virgo
These two elliptical galaxies of about 10th magnitude are visible in even a small telescope, just ¼ degree apart. Once you have spotted them, use a low-power eyepiece and slowly pan to the northeast. You are likely to run into more faint, fuzzy galaxies. This is the heart of the Virgo galaxy cluster.
Gamma Virginis
Double star in Virgo
This is a beautiful pair, consisting of a brighter yellow star and dimmer blue one, separated by 3 arcseconds.
Messier 3
Globular cluster in Canes Venatici
This is one of the brightest globular clusters in the sky. It can be seen any telescope, but the bigger the scope, the more impressive is the view.
Messier 97. The Owl Nebula
Planetary nebula in Ursa Major
This nebula is fairly large but dim. Through a telescope of medium aperture, it appears as a large circle of dim light. Two dark patches that make up the eyes of the owl are quite challenging to see even through large telescopes.
Messier 108
Spiral galaxy in Ursa Major
This galaxy is just 1 degree north of the Owl Nebula. Its oblong shape is obvious through a telescope.