Neptune will be at opposition – the middle of the best time to observe it – in the night between September 20 and 21.
Here is the eastward scene for a mid-USA location as Neptune comes up into view, on the evening nearest to the instant of opposition – which was about an hour earlier (when Neptune was on the horizon). There is little noticeable difference over a span of days before and after that instant.
You can see that the planet, being in the half of its 165-year orbit that lies south of the ecliptic plane, is passing half a degree south of the point we mark as the “anti-Sun” – 180° from the Sun.
That point, traveling along the ecliptic as the Sun does, was near Saturn – in other words, Saturn was at opposition – on Sep. 8.
And the Moon (exaggerated 4 times in size in our picture) was near the anti-Sun, that is, was full, on Sep. 18. Now it is rising, and bringing its glare into the sky, a couple of hours after Neptune.
So the best time to start trying for a telescope or binocular glimpse of the star-like dot of the bluish giant planet may be the time of the picture. At magnitude 7.8, Neptune is far below unaided-eye visibility.
There is much more on pages 126-127 of Astronomical Calendar 2024, and in our book Uranus, Neptune, Pluto.
Neptune, or at least his Greek equivalent Poseidon, was an interesting god. He was lord not only of the sea but the earthquakes. Almost as many chieftainly families claimed descent from him as from his brother Zeus. Associated with him was an aquarium of lesser marine deities – Amphitrite, Triton, the Nereids. Was one of them a fisher, or a sea cook?
Retrospective Corrections Department
I sometimes indulge in looking back at my piece about Long John Silver’s crutch and Treasure Island, which I called “an entirely successful book.” But I forgot to mention my one complaint about it.
“The Sea Cook” was Stevenson’s original title for the story; and Long John, though nominally the chief villain, is its outstanding character, indomitable and eloquent. Yet there is nothing – no detail – about how or what he cooked for the whole crew, as he hopped about his lurching kitchen on his wooden crutch.
So I’ve added a last-but-one paragraph, which may get me in trouble.
__________
This weblog maintains its right to be about astronomy or anything under the sun.
ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor.
One way: right-click, and choose ”View image” or ”Open image in new tab”, then enlarge. Or choose ”Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.
Sometimes I make improvements or corrections to a post after publishing it. If you click on the title, rather than on ‘Read more’, I think you are sure to see the latest version. Or, if you click ‘Refresh’ or press function key 5, you’ll see the latest version.