Night Sky Highlights for April-June 2017
Solar System
Lyrid Meteor Shower
This modest meteor shower peaks during the early morning hours of Saturday, April 22. The best part of the shower lasts only a few hours, when up to perhaps 10 to 20 meteors per hour might be seen. Some years, stronger bursts of meteors have been reported.
Comet 41P/Tuttle-Giacobini-Kresak
This periodic comet will be well placed for viewing in April and early May, passing through Ursa Major, Ursa Minor, and Draco. It could reach magnitude 5 or 6, and it should be easy to see through a telescope or binoculars if you know where to look. Here is a finder chart:
http://www.skyandtelescope.com/observing/worldwide-4p-comet-campaign-needs-your-photos/
Mercury
This spring, the only good time to see Mercury in the evening will be during the first few days of April, when it will be low in the west after sunset. Later, it will appear in the east just before dawn in the second half of May, but it will be quite close to the horizon and difficult to see.
Venus
Brilliant Venus will be in the eastern sky before dawn throughout the spring months, slowly getting higher in the sky as the weeks go by.
Mars
Mars will continue to be visible in the southwestern sky after sunset throughout the spring. It will be getting closer to the Sun as we approach summer. It is quite far from Earth and will display only a small red disk through a telescope.
Jupiter
On April 7 Jupiter will reach opposition (the point opposite the Sun in the sky), so it will closest to Earth at that time, and it will be visible all night long. By June, it will be high in the eastern sky right after dark and well placed for viewing.
Saturn
The ringed planet spends most of 2017 in Ophiuchus, and in April it will be rising in the east around midnight. By June, it will rise around sunset so it will be visible in the east later in the evening. From our angle, its rings will be wide open throughout the year, making it a wonderful sight through a telescope.
Uranus
Uranus is in Pisces, and it will too close to the Sun to see in April and May. By June, it will appear in the east before dawn. On June 3, Uranus will be 1.7 degrees north of Venus, making it relatively easy to find. To find it at other times you will need a map, and this article from the Sky & Telescope website includes finder charts for both Uranus and Neptune:
www.skyandtelescope.com/observing/planets/ice-giants-neptune-and-uranus/
Neptune
This outer planet is in Aquarius this year. It will be close to the Sun in April, but by May it will be in the morning sky before dawn. By mid-June it rises around midnight.
Deep Sky Objects
Messier 98 and 99
Galaxies in Coma Berenices
These two galaxies are part of the Virgo galaxy cluster, about 55 million light years away. Their shapes make an interesting contrast. Messier 98 is nearly edge-on so it appears very elongated. About 1.3 degrees to the east is Messier 99, a face-on spiral that appears round with a bright center.
Messier 100
Galaxy in Coma Berenices
Less than 2 degrees to the northeast of Messier 99, this is another face-on spiral galaxy. At magnitude 10 it sounds like M100 should be easy to spot, but its light is spread out over a fairly large area (about 6 arcminutes across), and its surface brightness is somewhat low.
Messier 64, the Black-eye galaxy
Galaxy in Coma Berenices
The bright nucleus of this oblong galaxy is very easy to see, and so is the large curving dust lane that gives the galaxy its name. At a distance of about 13 million light years, it is one of the nearer galaxies in our sky.
Messier 104, the Sombrero Galaxy
Galaxy in Virgo
This galaxy really does resemble a sombrero with it bulging nucleus and pointy spiral arms. It has a broad dust lane that is a bit challenging to see, but it can be detected under good conditions with a telescope of moderate size.
Messier 94
Galaxy in Canes Venatici
This oval spiral galaxy has a very high surface brightness, so it is not very hard to find. If you look closely around the edges of the bright nucleus, you may be able to discern some details in the tightly wound spiral arms.
NGC 4361
Planetary Nebula in Corvus
This round nebula can be found inside the 4 stars that form the most distinctive part of Corvus, the crow. Its angular size is just a little smaller than that of the M57, the Ring Nebula, but it is dimmer and harder to find. However, unlike the Ring Nebula, its central star of magnitude 13 is fairly easy to see through a telescope.
Mizar and Alcor
Double star in Ursa Major
This famous pair can be seen through much of the year, but it is high in the sky during the spring. Even in light polluted skies, it is usually possible to see these two stars with the naked eye, and through a telescope with low or medium power, Mizar resolves into a nice moderately close double star.
Polaris
Double star in Ursa Minor
Even most beginners can find Polaris, but many do not realize that it is a nice double star, though Polaris B requires fairly high power to spot because it can get lost in the glare of the primary star. Polaris A is magnitude 2, and Polaris B, 18 arcseconds away, is magnitude 9, a difference in brightness of more than 600 times.
Cor Caroli
Double star in Canes Venatici
Cor Caroli is the brightest star in Canes Venatici, and it is easy to find below the handle of the Big Dipper. It has a blue-white primary of magnitude 2.8 and a dimmer secondary of magnitude 5.6. They are separated by about 20 arcseconds, and the two can be easily seen in any telescope.