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Astronomy Fact of the Day

Fun astronomy facts to impress your friends with! 

Astronomy Fact of the Day for August 2017. 

Check back next month for more astronomy facts!

1st – August is the 2nd of two eclipse seasons this year. During an eclipse season you will have at least one solar and one lunar eclipse. The August 21 total solar eclipse is part of this season.

2nd – You can find Saturn about 3° south of the Moon tonight into tomorrow morning. The Moon will be exhibiting a waxing gibbous phase.

3rd – At 11pm look due south and you will find the Teapot asterism. This teapot shape of stars is how we identify the constellation Sagittarius. It’s spout points towards the galaxy’s center.

4th – Weather permitting, Public Telescope viewing will be held the James S. McDonnell Planetarium tonight. This event is co-hosted with the St. Louis Astronomical Society. For more information visit

5th – Today in 1969 Mariner 7 flew by Mars at a distance of 2,132 miles. The success of this mission was overshadowed by the Apollo 11 mission which occurred a few weeks prior.

6th – When you see the Moon tonight you will see large dark patches which are called Maria. These are what allows us to imagine patterns such as the man in the moon. See if you can spot this famous pattern and others such as a rabbit or an ant.

7th – Full moon occurs today at 1:11 pm. There will be a partial lunar eclipse on this date but it is not visible from the United States since it occurs before our moonrise.

8th – With less than two weeks to go before the 2017 solar eclipse are you ready to safely view the eclipse? To learn how to safely view solar eclipses visit NASA’s Safety 101 Eclipse page.

9th – If you look to the northwest around 9:30pm tonight you will see seven stars that form the Big Dipper. The Big Dipper is part of the constellation Ursa Major, the Great Bear.

10th – If you look the west around 10:00pm tonight you will see a group of stars that look like a kite. This group of stars is the constellation, Boötes, the Herdsman.

11th – Tomorrow the Perseid meteor shower peaks during our daylight hours. Your best chance to see meteors from the Perseids will be to go outside after midnight on the 12th and 13th.

12th – In 10 days St. Louis will see its first total solar eclipse since 1442. To find out where you should go to see totality visit NASA’s Eclipse Map.

13th – On August 21 the Americas will experience a solar eclipse. If you are looking for a place to view the eclipse visit Missouri Eclipse 2017.

14th –We are a week away from the 2017 solar eclipse. Will you be in the dark? Visit NASA’s 2017 Eclipse Website to learn more about the eclipse.

15th – With less than one week to go before the 2017 solar eclipse are you ready to safely view the eclipse? To learn how to safely view solar eclipses visit NASA’s Safety 101 Eclipse page.

16th – The August 21 solar eclipse will be the first total solar eclipse visible from St. Louis since July 7, 1442 and will be the last until the June 3, 2505.

17th – In 5 more days the 2017 solar eclipse will be upon us. To see totality many of us will have to travel which will make traffic a serious concern. If you have to travel to totality, visit Great American Eclipse’s predicting eclipse visitation with population statistics to help make your travel plans.

18th – Today the Moon will be at perigee which is when it is closest to Earth. Total solar eclipses occur only at new moon when it is near perigee. This will be the circumstance on August 21.

19th – An eclipse is a syzygy. This is a straight-line configuration of three or more celestial bodies in a gravitational system. From Earth we see eclipses of the Sun and Moon. Other syzygies are occultations and transits.

20th – Solar eclipses only occur during new moon. Typically every month has a new moon but every month does not have a solar eclipse. This is due to the Moon’s orbital tilt in regards to Earth’s ecliptic.

21st – Today the 2017 solar eclipse occurs. Most of the Americas will see a partial eclipse but a 71 mile wide path in the US will see a total solar eclipse. It starts in St. Louis around 11:49am. To learn more visit NASA’s Eclipse Map.

22nd – If you missed yesterday’s solar eclipse you have a chance to see another on April 8, 2024. Totality will not be seen in St. Louis but can be viewed from SE Missouri and southern Illinois.

23rd – Beware the Mars Hoax. Every August an email circulates that Mars will appear as big as the moon. Currently Mars is not visible but when it is it will never appear the size of the Moon in the sky.

24th – Looking south at 9pm you will find the planet Saturn. It is currently found in the 13th zodiac constellation called Ophiuchus the Serpent Bearer.

25th – Tonight you will find the waxing crescent moon, Jupiter and the bright star Spica together in the west. You can find the grouping low in the west around 8:30pm.

26th – Today Mercury will pass between Earth and the Sun a point called inferior conjunction. Unfortunately, it will not be a syzygy so no Mercury transit will occur. The next Mercury transit occurs on Nov. 11, 2019.

27th – Looking east tonight around 9pm you will find a bright square shape of stars. This is called the Great Square of Autumn.

28th – Today a SpaceX Falcon 9 rocket will launch the Air Force’s X-37B Space Plane This is a robotic spacecraft that resembles the Space Shuttle but is much smaller.

29th – The dwarf planet Pluto takes roughly 248 years to orbit the Sun. Since its discovery Pluto will complete its first orbit in the year 2178.

30th – Today the Moon is at apogee. This is when the Moon is at its greatest distance from Earth for the current lunation. At apogee the Moon can appear about 14% smaller than when it is at perigee.

31st – Saturn has 62 moons. One named Enceladus has been found to have liquid water and hydrothermal vents under its frozen surface. Discoveries like these suggest it is possible life could develop there.

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