These are the good old days. Every planet except for Mars is striking and changing rapidly. Come back this Thanksgiving, though, and the sky will be empty: no planets at all. So right now, this is the time.
Pluto of course is making the news. We just got our best close-up views right before this newspaper went to print. So I can’t comment yet, but I expect that it’s all very exciting and unpredicted. Meanwhile, Venus is going through rapid changes.
It has been in the west after sunset since January. We’ve grown accustomed to it. Its brightness has only slowly altered. We watched as it met the Moon a few weeks ago and then had a wonderful conjunction with Jupiter, which remains to its left. But now it changes rapidly, and shouldn’t go unobserved.
First off, it’s at its very brightest. You just can’t miss it, say at 9:15 p.m. in the direction of sunset. It’s the brightest thing in the sky, at magnitude -4.7. But each evening it’s noticeably lower. In our hilly region, that’s not good. There will come a time in the next week or two when it’s simply too low in fading twilight, as seen from your home. Still, from places with clear western vistas, like the Walkway over the Hudson, or any of the Kingston malls, it will remain visible right through the end of this month.
The reason this matters is that as Venus now slides between our world and the Sun, it’s increasingly close and also increasingly lit up from the back side, making it look like a little crescent moon. Any small telescope, any magnification, even image-stabilized binoculars show its crescent shape. Each evening its crescent grows larger but narrower, making it ever more striking.
These fast alterations in its appearance and position only happen when Venus is closest to us – the reality during the next month. Then, bam! In mid-August it invisibly passes between us and the Sun, then emerges by month’s end as a gorgeous morning star for the rest of the year.
Fast changes, worth our awareness. As for the other planets, Jupiter (the other bright star low in the west) will remain to Venus’ left. It too is dropping like a lead ball, lower down each evening at twilight. It too will soon disappear. Saturn in Scorpius is finishing its retrograde motion, and is that one bright (but not brilliant) “star” low in the south – to the right of the red star Antares.
And Pluto – well, it’s now a new world entirely. Mid-July 2015: a kaleidoscope of super-fast planet changes. Backyard telescope, binoculars or just your eyeballs: Use whatever you’ve got.
Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.