Oh yes. Occult. Exciting right? Those of us in LA and some other areas (apparently points in Nevada, Idaho, and Western Montana, and the cities of Calgary and Edmonton) will see have the chance to see something quite remarkable if we stay up until 03:34 Pacific time (i.e., early morning April 6th). I learned this from Phil’s blog. You can find out more from Sky and Telescope (that’s their figure on the right). The event is this. If you stare at the star ζ (Zeta) Ophiuchi, which is visible to the naked eye, it will go dim for about eight seconds. Why, because an asteroid (824 Anastasia) will pass directly in front of it. You can’t see the asteroid directly, since it is too small and too dim, but nevertheless its presence between you and the distant star will be enough to make it go dim for a bit. Isn’t that wonderful? Have a go!
This remarkable effect (called occultation – hence the sneaky blog post title: the key root meaning here is “hidden”), while it might seem rather mundane in some ways (although you’re seeing the effect of an asteroid with your own eyes!) is extremely powerful in astronomy. It is a great way, for example, of detecting planets orbiting other stars! You’re familiar with occultations already actually. When the moon moves in front of the sun – a solar eclipse – that’s an occultation. Of course, in that case, it is not the method you used to detect the existence of the moon. You’d no doubt noticed it before.
Now, do consider getting up briefly to see the event. If you do, make sure your watch is accurate and consider timing the occultation (when the star goes dim and when it comes back up). Why? Your data will be useful to the astronomers in learning about the shape and size of the asteroid. You can send it in. Look at the Sky and Telescope site for more.
Enjoy!
-cvj
Hi,
Well, no sighting is also data for them, so your efforts were not in vain… I will be especially nice to my alarm clock for a while. Buy it flowers and so forth.
-cvj
From the IOTA initial report (http://www.asteroidoccultation.com/observations/Results/), the occultation track was a considerable distance west of the prediction. There are three positive results so far, from Castaic, Thousand Oaks and Fillmore. There was a narrow miss at Canoga Park, and no-one east of there will have seen an occultation.
Clifford, it sounds like your alarm clock was your friend last night!
Cheers,
Peter
Hi Peter… I see. I’m embarrassed to say that I woke up rather late after only getting to sleep at 2:00am. So I do not know what happened over Los Angeles.
I hope others who might have looked might report in…
Best,
-cvj
Thanks, Clifford. Well, as far as I can tell, nothing happened here. It’s amazing how difficult it is to concentrate totally on one star (or, I suppose, one anything else) for ten to fifteeen minutes, but, that said, I’m pretty sure there wasn’t an occultation from here in Laguna.
Back to bed now.
Hi Peter. Thanks! We shall see. I’m going to try to get up and look as well, although given that I’m going to sleep at 1:35am, I’m a bit worried my alarms won’t help much…
Nice blog, by the way!
-cvj
I think it’s a little more than the star going dim. What should happen is that the star, in effect, winks out. In other words, it should disappear entirely, and essentially instantaneously, for a few seconds before winking back in again.
One of the most interesting aspects of this event is that we don’t exactly know the asteroid’s orbit, so we don’t exactly know who will see an occultation and who won’t. The best guess seems to be that the centre of the track will pass more or less over my home in Laguna Beach, so I’m going to try to haul my lazy ass out of bed to watch, armed with the Atomic Clock app on my iPod and a pocket voice recorder.
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