Distant Worlds and Pale Blue Dots

Astronomical Events for August 25th, 2015

Just last month, we made history as New Horizons became the first space probe to visit the dwarf planet Pluto and its moons. When the probe was first launched, Pluto was still a fully-fledged planet and the last time we explored a planet for the first time was on this date, August 25th, in 1989.

The space probe was Voyager 2, the planet was Neptune and it was the last stop in a “Grand Tour” that included Jupiter in 1979, Saturn in 1981 and Uranus in 1986. Until then, no one had ever seen Neptune close-up and in a time before the Hubble Space Telescope, the best images of the distant world were nothing more than indistinct, fuzzy blobs.

Voyager 2 brought the planet into focus and showed us a stunning, deep blue world of white clouds and cyclones. One large, blue eye, reminiscent of Jupiter’s Great Red Spot, stared back at the probe as it sped past at a distance of just under 28,000 miles. Faint, dark rings were discovered encircling the planet, as well as a number of tiny new moons.

Of course, we still have those images to enjoy today, but if you want to view the planet for yourself, you’ll only need a pair of binoculars and a small telescope. But be warned; finding Neptune is not for the faint of heart. Although the planet rises mid-evening and the images above will give you a rough idea of its location, a good star chart or app (such as Mobile Observatory) will help you pick the planet apart from the neighboring stars.

The images above show Aquarius in the south-east at about 11:00 p.m. from the northern hemisphere. Through a telescope at low power, the planet appears as a sky-blue untwinkling star and you’ll probably need a magnification of about 150x to see any kind of a tiny disk. Some might be underwhelmed by the sight, but remember this: as unassuming as Neptune appears, this giant could hold nearly sixty Earths within it and has recorded wind speeds of 1,300 mph.

As you stare at the pale blue dot, remember that it was less than a year later, at a distance of some 3.7 billion miles, that Voyager 1 captured the solar system’s other pale blue dot, caught in a distant sunbeam. The Earth. Our world. The only place we can call home.

The Earth, our home. (Credit: NASA)

The Earth, our home. (Credit: NASA)

(Click on an image to enlarge. Adapted from 2015: An Astronomical Year, available in Kindle and paperback formats from Amazon in the US, Canada and the United Kingdom.)

Star chart images courtesy of Mobile Observatory. Neptune image credit: NASA/JPL



Events in bold involve objects and/or events that are visible with the naked eye.

All times are in Universal Time (UTC). To convert the time to your timezone, click here.

2015 An Astronomical Year (Kindle Edition) 2016 An Astronomical Year Paperback Cover 2016 The Night Sky Sights The Astronomical Almanac 2015-2019

2015: An Astronomical Year

2016: An Astronomical Year 2016: The Night Sky Sights The Astronomical Almanac (2015-2019) The Amateur Astronomer’s Notebook (Pocket Edition)

(Kindle & Paperback)

(Kindle & Paperback) (Kindle & Paperback) (Kindle & Paperback)


Amazon – US

Amazon – US Amazon – US Amazon – US Amazon – US
Amazon – UK Amazon – UK  Amazon – UK Amazon – UK

Amazon – UK

Details of all available books across the world can be found here or by visiting the author’s page on Amazon. If you have any comments or questions, please feel free to contact me at astronomywriter “at” gmail.com


One thought on “Distant Worlds and Pale Blue Dots

  1. Pingback: The Best Night Sky Sights for September | The Astronomical Year

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