Next few evenings backyard astronomers get a chance to see two worlds in the extreme – Venus and Neptune – in the same part of the sky. The brightest and faintest planets visible to skywatchers will be huddling together in a close conjunction in the south-western sky after sunset.
While Venus is super easy to see with the naked eye because it shines like a white beacon, Neptune is so faint it can only be glimpsed with binoculars and telescopes. While this means the 8th and most distant planet in the solar system is usually quite a challenge even for seasoned stargazers to hunt down, you are in luck to have Venus act as your guide.
On January 13th the two planets will appear to be only 1 degree apart, and by the next night they will still only be separated by just under 2 degrees (2 full moon disk equal 1 degree in the sky). This means the Venus and Neptune will be well within the field of view of low a magnification eyepiece through a small telescope on Jan.13th. Astro Bob offers a nice closeup skychart for the Jan.13 conjunction. Both planets will then stay within the field of view of a standard pair of binoculars (7 degrees) for nearly another week as Neptune continues to sink towards the horizon while Venus rises ever higher. Remember that because the planets will b e in the lower one third of the sky, you need to have clear line of sight low to the horizon. Timing also will play a part, limiting your viewing window as the planets will follow the sun and set within two hours.
Neptune won’t reveal much detail, even under high magnification , other than it is a blue, tiny disk set against the black inkiness of space. Still amazing though since its more than 4.6 billion km from Earth. Compare that to Venus which is only 181 million km distant. So it’s no surprise then that Venus at Magnitude – 4, shines about 60,000 times brighter than Neptune at Magnitude + 8.
Venus however is a different story when it comes to magnified views. Even high-power binoculars and small telescopes will reveal the phases of Venus as it orbits the Sun, but keep in mind no telescope will show surface details because its globally covered with white clouds. But still, watching it go through thru its phases like the moon is really fun and easy to do.
Look closely through your telescope under high magnification throughout January and you can comfortably observe that Venus is not a round disk but looks just like a miniature waxing gibbous moon-about 80% of its disk illuminated. I never get tired of checking this celestial goddess out in the skies above!
Skywatching Extra: Late Friday, Jan. 13th into dawn on Saturday Jan. 14th check out the waxing gibbous moon only 8 degrees below ruddy star-like Mars. The cosmic duo will appear closer together in the sky than the width of your clenched fist at arms length. Quite a pretty pairing!
At Dawn on Jan.16 and 17 the moon will pass just below the ringed planet Saturn and the bright star Spica. Check out my skychart with more observing details.
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.