29 Jun 2009
The sky is vast. I mean vast. But one would think that with all the telescopes we have now probing through the heavens every night that almost nothing would escape our notice. Right? Wrong.
The scopes that we have now are powerful, to be sure, but are completely focused on just infinitesimal specks of sky. Even if hundreds of scopes are up at any given moment, most heavenly events go completely unnoticed.
That is why one of the latest technical innovations just hitting the airwaves holds such great promise. And it is happening on our very own Palomar Mountain in a project called the Palomar Transient Factory (PTF) survey.
We all know of The Telescope on Palomar, the 200-inch Hale inside that monstrous white dome. But there are other scopes there, as well, contributing nightly to the advancement of astronomy.
One is the Samuel Oschin 48-inch Telescope located in a dome just a stone's throw away from the Big One.
What is special about this scope is that it has an amazingly wide field of view, covering an area of sky greater than 15 Full Moons; no speck of sky here. And it has a huge digital camera attached, 100 megapixels strong to be exact. So what? So this:
In days of old, astronomers would spend literally hours trying to expose just one tiny fleck of sky onto a photographic plate. Now, the camera mounted on the Samuel Oschin scope with that super-sized, superfast camera can take over 100 gigabytes worth of images a night. That's enough info to fill an average computer hard drive. But that's not all!
In days of old - well, even now - astronomers then have to pour over those images and look for stuff that's new or different. That consumes a lot of time.
The PTF survey is set up so that it can take all those images and send them wirelessly to computers which then sift through the images automatically to search for new objects.
If the computers find something out of the ordinary, they can alert observatories throughout the world, giving them a "heads up" that maybe something worth looking at is in a particular part of the sky. The PTF survey is putting a million eyes on the sky at once.
What can it detect for us? All kinds of supernovae, cataclysmic variable stars, possible planets around other stars, near-Earth asteroids, oh my! And it finds them fast.
"Today I found five new supernovae before breakfast," says Caltech's Robert Quimby, a postdoctoral scholar and leader of the PTF software team. "In the previous survey I worked on, I found 30 in two years."
Modern technology combined with a workhorse telescope are adding to our rapidly growing knowledge of our beautiful universe. Go team!
15 Jun 2009
In the next days we mark an anniversary of a discovery made in 1978 that wasn't exactly an earthshaker, but is an interesting look into astronomy, nonetheless.
You may recall that Pluto was discovered in 1930 by a young astronomer Clyde Tombaugh. He noticed that in several images of a particular part of the sky taken some time apart that the stars were stationary as expected, but that there was a small dim dot moving slowly through them. Long story short: It was Pluto.
Those were more simple times, when a new spherical body in space found in an orbit all by itself would just naturally be christened a new planet, no questions asked. And it was a time when a body revolving around a planet would just naturally be called its moon.
Well, in 1978, on 22 June to be exact, astronomer James Christy noticed that the best images we could get of Pluto back then periodically showed a slight bulge. It turns out that that bulge was not the result of crummy photography, but was really a small spherical body circling Pluto. Christy had discovered a wee moon around tiny Pluto!
Legend has it that he named the new moon Charon, after his wife Charlene, whom people called "Char" for short. This kind of went against the tradition of naming heavenly bodies after Greek or Roman mythological beings. But lucky him, Charon was also the name for the mythical boatman on the river Styx, the one who ferried souls off to Hades. So Charon stuck.
There they were, Pluto and Charon, planet and moon, living happily together. Until recently that is.
You may recall that Pluto has had some problems lately among astronomers. It was demoted from planet to... well, all kinds of things: dwarf planet, transneptunian object, Kuiper Belt Object.
If Pluto is a dwarf planet then it might follow that Charon is just a moon of a dwarf planet. But - surprise! - it is more complicated than that.
Pluto and Charon are both pretty similar in size, so much so that Charon doesn't really go around Pluto like the Moon around us - a little guy circling about a barely moving big guy. Pluto and Charon's mutual center of gravity is somewhere between the two in space. They are more like two people holding hands and spinning around and around some common center between them, rather than like a stationary person swinging a ball around on a string.
This is disturbing enough for some astronomers that Charon and Pluto are being looked at as a possible dwarf planet duo.
What is Charon's status at the moment? It is still a moon by most accounts, at least until the International Astronomical Union officially defines what a large moon of a dwarf planet is. Sheesh!
O, for the simpler days when there were but mere "planets" and "moons"!
01 Jun 2009
The nighttime is the right time for seeing planets this month - the whole night through. Whether you go to bed early, get up early, or get no sleep at all, there are planets on parade all through the dark hours in June. Let's start our survey in the early evening.
Saturn is in its last act for this year. The great ringed planet is on its way around the sun to the other side. You can find Saturn in the western skies after sunset. Here's a little help: In the 8 o'clock hour go outside and face southwest. Estimate about two-thirds up between the horizon and the point over your head. Saturn is the golden star-looking creature there. If you know your constellations, it is on Leo's hindquarters.
Try and get a telescope this month to take a gander at Saturn. In the next month or so it creeps closer and closer to both the sun and the horizon, both of which severely impede our attempts to view celestial bodies.
For the night owls amongst us, Jupiter wakes from its sleep in the east after one in the morning. And as June moves along and we get into July and August it will rise earlier and earlier. You cannot miss it coming over the horizon. But if you are trying to see it through a scope, wait, if you can, for a few hours until it rises above the annoying horizon.
Bonus planet: You can see Neptune this month much easier than at most times by using nearby Jupiter as a guide.
Neptune leads Jupiter through the sky, staying just ahead of the Giant. With a steady pair of binoculars you can spot Neptune just to the northwest of Jupiter. With a telescope you can see the bluish disk of the ice giant. I have a star chart and a movie of the two planets dancing through the skies for the next month and a half with each other.
Here is the starchart for Neptune and Jupiter.
Here is the movie. (Starts 1 June, every frame equals one day)
Now a special treat for the early morning risers: There seems to be some sort of terrestrial planet general meeting going on this month in the eastern skies.
You may have noticed, if you are up before sunrise, the brightest of all planets, Venus, rising in the east. She's an easy one to spot. But have you noticed next to her Mars, the tiny pinkish dot? They are our morning stars, so to speak, and they will be joined on the 19th by tiny Mercury and a beautiful crescent Moon.
Mark your calendars for that date. You will get to see, in the same patch of sky, Mercury, Venus, Mars, the Moon, and even the Pleiades as a starry guest star.
Here is the starchart. (5AM 19 June)
June is a planet-filled month. Try and make an effort to spot a few.