Saturn Better Late than Never

It’s the last day of June and is Saturn’s-day, and I can at last issue my delayed article about the mighty planet.

I had all of the following ready on June 21, in good time to publish it at least a couple of days before Saturn’s June 27 opposition.  But, as explained in the stopgap notice I managed to send (using an iPad and a public library) on June 26, our telephone and internet were cut off by a snafu of the phone company, at a time that could hardly have been worse, while we were away on a journey.  And there was something even more important that I wanted to send you next.  Watch out for news of a trio of planets beyond Saturn.

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Here is Saturn rising in the southeast, as seen from America on the evening before its opposition.

Opposition from the Sun is the middle of the best weeks for viewing a planet, since it is about nearest, brightest, and \highest – on the southern meridian of the sky at midnight.

However, the more precise moment of the event is 13 hours Universal Time, which is in high daylight for Europe and in morning daylight for most of America, so I show the scene on the preceding evening.

Like any planet around opposition, Saturn is appearing to move slowly backward (westward, “rightward”) among the stars, because we are overtaking it on the inside.  You can see that it is passing just north of the imaginary “anti-Sun,” or shadow of the Earth.

Unfortunately the Moon, rushing from the contrary direction, is also about to meet the anti-Sun – in other words, to be Full.  It passes about 2 degrees north of Saturn on June 28 at 4 UT (just over a day from the picture time), and is exactly Full only about an hour after that.

In the picture, the Moon is exaggerated 2 times in size, and the ringed planet 150 times.

It may be better to view Saturn in succeeding nights, when its position has not much changed but the Moon has rushed on and is dwindling and rising later.

Saturn and the Full Moon are rather low on June nights, because they are on the southerly part of the ecliptic.

Here is a chart of Saturn’s path throughout 2018, among the stars of Sagittarius.

For this chart I added to my program a symbol for the planet at its opposition, for comparison of its brightness with the stars.  Then I thought of showing it also at the other extreme, the date of conjunction with the Sun, when it is farthest and dimmest and indeed hidden.  But no such Saturn appeared.  Of course.  For this happens to be a year when Saturn is not at conjunction with the Sun at all.  Opposition being near the middle of this year, Sun-conjunction has to be near the end.  In fact the last was on 2017 Dec. 21 and the next will be 2019 Jan. 2.  Such years without Sun-conjunction have to occur at intervals of the planet’s orbital periodm which for Saturn is about 29 years, and indeed the last such year was 1989.

It may (to repeat) be better to view Saturn in succeeding nights – indeed, I’m not sure whether you’ll get my Saturn-bulletin in time to do otherwise.  Although I’m writing it four days in advance, a foreign journey, an eye operation, and a loss of telephone and internet have joined forces with the Saturn-obscuring glare of the Moon.