This April should be a great month for sky watching. Every year, April is the best month to see nearly every key star and constellation in the Hawaiian night sky, literally from the North Star to the Southern Cross.

Most of the planets also put in a good appearance here this April.

“North Star to Southern Cross” is the name of a well-known sky guide by Will Kyselka, who was a planetarium lecturer at the Bishop Museum in the 1960s into the 1980s. “North Star to Southern Cross” was the first astronomy reference book I bought when I started my planetarium career in Seattle, long before I came to work in the same planetarium theater as its author.

While Kyselka’s book, which is still in print, is an excellent guide to the night sky for anyone in the continental United States, its title refers to something that is specific to Hawaii among the 50 states: we are the only state where you can see the whole expanse of stars from the North Star to the Southern Cross. April is a good time for this, with the Big Dipper high overhead, the Little Dipper and the North Star visible as always, and the Southern Cross coming up in the evening sky.

The museum’s April star map illustrates this. Like all of our monthly maps, this one is good for 10 p.m. on the first day of the month, 9 p.m. for the middle of the month, and for 8 p.m. at the end.

The Little Dipper, which contains the North Star at the end of its handle, should be visible from a clear dark sky, as the dipper is no longer plunging straight at the horizon.

You can use the handle of the Big Dipper to “arc to Arcturus,” the brilliant star in Bootes that is known as Hokule‘a in the islands. You can keep on going to “spike to Spica” in Virgo, and continue all the way to the Southern Cross, just rising in the east-southeast at map time. The Southern Cross itself is small and compact and hugs the horizon. Find a flat southern horizon, such as looking over the ocean, to see it.

Here in April, the great winter constellations are also still visible. They are now low in the west; the parade includes Orion, Canis Major, Auriga, and Gemini. Meanwhile Leo, the classic spring constellation and the first of Hercules’ 12 labors, is in the center of our April sky. Below Leo is the second labor of Hercules, the snaky constellation on Hydra.

On this April map, Orion is just about to set in the west. Once he is gone (about three hours after map-time), his nemesis, Scorpius the scorpion, will be visible in the east-southeast.

April planets

Jupiter is the only planet visible throughout the month. The planet is the brightest dot in the evening sky, several times brighter than the brightest star. Throughout the month, it lies just below Leo.

In early April, look for Jupiter a third of the way up in the east at dusk. Jupiter crosses the top of the sky at 11 p.m. in early April and sets in the west at 5 a.m. By the end of April, look for Jupiter two-thirds of the way up in the east at dusk; it will be high in the south by 9 p.m., and sets in the west at 3 a.m.

Mars will be at its brightest in 10 years in May. As it heads to this peak, you will see it increase dramatically in brightness in April.

Mars rises in the east at 11 p.m. in early April, amid the stars of Scorpius. Throughout the month, Mars will be just above Antares, the brightest star in the Scorpion. Mars will be in fact about six degrees above Antares in April, which is the width of three fingers held at arm’s length. Antares has a similar orange color to Mars, and its name means “Mars’ rival,” after the Greek god of war, Ares. However, while the brightness of Antares will remain steady, at 1.03 magnitude, Mars above it will double in brightness this month.

You can use Antares to observe the change in the red planet’s brightness. In early April, Mars shines at minus 0.5 magnitude, already somewhat brighter than Antares. By the end of April, Mars shines at minus 1.4 magnitude, which is almost exactly the same brightness as Sirius, the sky’s brightest star. By the end of the month, Mars far outshines Antares, just below it.

Mars rises at 11 p.m. in early April, is halfway up in the south at 4 a.m., and is still partway up in the west by daybreak. By the end of the month, Mars rises at 9 p.m., is due south at 2:30 a.m., and is a third of the way up in the west at dawn.

Saturn rises in the east about 30 minutes after Mars. Throughout April, Saturn is just a little less than a palm’s width to the left of Antares while Mars blazes above both Antares and Saturn. In fact, Saturn, Antares and Mars make a nice triangle all month, with Mars on top. Saturn shines bright all month, and its pale yellow-white makes a nice contrast to the orange blaze of Antares and Mars.

Mercury has its best evening appearance for 2016 in April. Look for it as early as April 5; if you look west at 7:15 p.m., Mercury shines at minus 1.16 in the dusk, about 5 degrees (three fingers) above the horizon. You will have 30 minutes to catch it before it sets at 7:45 p.m. By April 18, Mercury will be 10 degrees above the horizon at dusk (one palm’s diameter), setting at 8:15 p.m. After that, you’ll have only a few more days to catch Mercury; it will be lost in the dusk light by about April 25.

Mercury can be tricky to find, always huddling low near the horizon at dusk or at dawn. On April 8, the slender crescent moon can help. Look for the moon low in the west around 7:30 p.m. Mercury is the bright dot to the moon’s lower right.

Mike Shanahan is the director of visitor experience and plan- etarium at Bishop Museum. He can be reached at mikes@bishopmuseum.org.