Here by request is Vesta, the asteroid that was fourth in order of discovery, (in 1807, by Olbers) but that is able to become the brightest.
See the end note about enlarging illustrations.
As yet, Vesta is out in the morning sky, still about 2.5 astronomical units (Sun-Earth distances) from us, and has reached a magnitude of 8.2 – findable with binoculars – just east of the star Mu Ceti in the “head” of Cetus the Whale.
When we pass Vesta at opposition in November, she will be only 1.57 a.u. away and the brightness will have risen to magnitude 6.5: just about the naked-eye limit. That is not up to the magnitude of 5.2 that Vesta can reach in the best years.
In this sky scene for the pre-dawm of July 11 –
– Vesta is 30° above the horizon.
By the way, I’ve tried curving the horizon more gently, by setting the viewpoint as 5 instead of 10 degrees below it. Maybe that is more of a compromise between the general expectation that the horizon is flat, and my liking for some convex curvature so as to remind us that we are on a planet. The horizon is a great circle, and we can decide arbitrarily what curvature, if any, to give it in a picture.
We should return to Vesta nearer the time of opposition, and maybe indulge in discourse on goddess Vesta, the Vestal Virgins, Vesta matches, and the reasons why the asteroid is bright.
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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”, 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.
Thanks, Guy, for this one, although I’m not the one who requested it. I’ve seen all sorts of sky amazements; phases of Venus, moons of jupiter and rings of saturn, even spotted Neptune in my heyday but have yet to see an asteroid. I miss your hard copy of your calendar, but I’ll certainly be setting up to see this appearance of Vesta. Thanks.
Thanks Guy, you’re very kind.
No luck seeing Vesta yet, due to morning clouds and fog. I’m not complaining though, because when the summer morning sky is clear here in San Francisco the day will be hot.
I looked at the wikipedia article on Swan Vestas, “the original smoker’s match”. I suppose you could use one to light the vestal fire, but lighting a cigarette would offend against Vesta’s devotion to health and hygiene!
I saw Vesta a few years back using a monocular,seen Ceres too and this year added Pallas to the astroid belt objects I’ve see.