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Astronomy Fact Of The Day

2018
April 1

Tomorrow morning around 3:30am you will find the planet Mars and Saturn close together in the southeastern sky.

Tomorrow morning around 3:30am you will find the planet Mars and Saturn close together in the southeastern sky.
April 2

Mars is about 4 months from opposition. This configuration of Mars occurs on July 26/27 and is when Mars will be at its brightest. With a telescope you will be able to see the surface of Mars.

Mars is about 4 months from opposition.  This configuration of Mars occurs on July 26/27 and is when Mars will be at its brightest. With a telescope you will be able to see the surface of Mars.
April 3

Orion contains two of the ten brightest stars in the night sky. Betelgeuse is the 10th brightest and Rigel is the 7th brightest star. Orion is visible in the west around 9pm tonight.

April 4

The Apollo 11 mission featured lunar and command module guidance computer programming by MIT programmer Margaret Hamilton.

The Apollo 11 mission featured lunar and command module guidance computer programming by MIT programmer Margaret Hamilton.
Learn more about Margaret Hamilton.

Come to the Saint Louis Science Center and see the Apollo 11 space capsule in our special exhibition Destination Moon: The Apollo 11 Mission!
April 5

Thanks to liquid recycling techniques in Apollo missions, kidney dialysis technology was advanced. Check NASA spinoffs to learn more about how NASA innovations affect your everyday life.

April 6

Public Telescope Viewing will be held at the James S. McDonnell Planetarium tonight with the St. Louis Astronomical Society.

Public Telescope Viewing will be held at the James S. McDonnell Planetarium tonight with the St. Louis Astronomical Society.
For more information view our Public Telescope Viewing information
April 7

Mars is the 4th planet from the sun. It takes about 687 Earth days to complete one orbit. Because Earth orbits faster we catch up to Mars every 26 months and opposition occurs.

Mars is the 4th planet from the sun.  It takes about 687 Earth days to complete one orbit.  Because Earth orbits faster we catch up to Mars every 26 months and opposition occurs.
April 8

Last quarter moon occurs today. This is a good opportunity to grab some daytime views of the moon before it sets at 12:26 pm.

Last quarter moon occurs today.  This is a good opportunity to grab some daytime views of the moon before it sets at 12:26 pm.
April 9

James S. McDonnell was born on this date in 1899. He started his first company in 1928, to build the Doodlebug, before founding St. Louis-based McDonnell Aircraft Company in 1939.

April 10

Even though it is spring we can still see the Winter Circle. Looking to the southwest around 9pm tonight you will see six bright stars that form the Winter Circle!

April 11

Look north around 9pm and you will find the Big Dipper. If you follow the two stars at the end of its bowl you can find the current North Star named Polaris.

April 12

On May 5 NASA will launch the next Mars lander called InSight. This mission is intended to study the crust, mantle and core of Mars. This is the first robotic mission to study the interior of Mars.

April 13

Look to the north at 9pm and you will find the Big Dipper. If you follow the curve of its handle it will point you to the bright red giant star Arcturus. This star is about 25 times larger than the sun.

April 14

This year, two missions will visit asteroids with the goal to return samples to Earth. In June JAXA mission Hayabusa 2 will visit Ryugu and in October NASA mission OSIRI-REx will visit Bennu.

April 15

Mars is about half the size of Earth and like Earth it is a rocky planet. By studying these rocks scientists have been able to show that Mars once had large amounts of liquid water on its surface.

Mars is about half the size of Earth and like Earth it is a rocky planet.  By studying these rocks scientists have been able to show that Mars once had large amounts of liquid water on its surface.
April 16

New moon occurs today at 1:57am. By sunset the moon will be a waxing crescent phase that is only 18 hours into the lunar cycle.

New moon occurs today at 1:57am. By sunset the moon will be a waxing crescent phase that is only 18 hours into the lunar cycle.
April 17

Tomorrow morning the planet Saturn will rise around 1am. Saturn will be at aphelion which is its farthest point from the Sun. Saturn orbits the sun every 29 years so its next aphelion will be in 2047.

Tomorrow morning the planet Saturn will rise around 1am.  Saturn will be at aphelion which is its farthest point from the Sun. Saturn orbits the sun every 29 years so its next aphelion will be in 2047.
April 18

The bright star Vega can be found in the east by midnight. This star is in the constellation Lyra the Harp. The upcoming Lyrid meteor shower appears to come from the direction of this constellation.

April 19

On this date in 1971 the first space station, Salyut 1, was put into orbit.

April 20

The annual Lyrid meteor shower will be reaching its peak on April 22. Over the next three days your best chance to see this meteor shower will be to step outside at 3am.

April 21

Celebrate Astronomy Day today at the James S. McDonnell planetarium. There will be safe solar observing from 10am to 2pm weather permitting.

April 22

Mars has two moons named Phobos and Deimos. These moons were likely asteroids captured by Mars. They are similar in composition to objects called carbonaceous chondrites.

Mars has two moons named Phobos and Deimos.  These moons were likely asteroids captured by Mars. They are similar in composition to objects called carbonaceous chondrites.
Phobos On Top
Deimos on the Bottom

Learn about the moons of Mars.
April 23

The planets travel through a path of 13 constellations known as the Zodiac. This path is called the ecliptic.

April 24

Tonight the moon will exhibit a waxing gibbous phase with about 63% disk illumination. The bright star east if the moon is Regulus. This is the brightest star in the constellation Leo.

April 25

Looking toward the south around 4am you will see a group of stars that look like the letter “J”. This is the summer constellation Scorpius the Scorpion.

April 26

On this date in 1962 Ariel 1 was launched. This mission was the first satellite operated by the United Kingdom making them the third country to operate a satellite.

April 27

On July 27 Mars will reach opposition with Earth becoming brighter and closer than it normally is. This occurs every 26 months providing observers a chance to view the surface of Mars through a telescope.

April 28

NASA has sent four rovers to the planet Mars. The first was Sojouner, followed by the twin rovers Spirit and Opportunity and the last was Curiosity. NASA will send a 5th rover in 2020.

April 29

Full moon occurs tonight around 8pm. During full moon the moon appears much brighter. This occurs because of the opposition effect which occurs because shadows cast on the moon are pointed away from the observer.

Full moon occurs tonight around 8pm.  During full moon the moon appears much brighter.  This occurs because of the opposition effect which occurs because shadows cast on the moon are pointed away from the observer.
April 30

You will currently find the planets Mars and Saturn together in the constellation Sagittarius. Saturn rises around 12:30am and Mars rises around 1:30am.

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