Monthly Archives: August 2013

astronomy

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Perseid Meteor Shower Inbound

This time every year we get to enjoy the Perseid Meteor shower. It begins in late July and normally peaks around in the second week of August. This year the best viewing time is early in the morning of August 12th, and you’ll have to stay up to the wee hours (or get up early) to catch the peak of the shower during that time. Or, you can Perseid-gaze late at night, although you may not see quite as many as you would if you looked during the peak hours. Simply find a time when you can step outside around midnight and wait for a bright flash of light to flare through the sky from roughly the direction of the constellation Perseus. It appears very low above the eastern horizon, but you’ll likely spot meteors in many parts of the sky.

If you do see one (and chances are you’ll see more than one if you stay out any length of time), you’ll be witnessing a piece of solar system history flash across your field of view. It will be a tiny piece of debris left behind by the Comet Swift-Tuttle as it rounds the Sun. Comets date back to the earliest history of the solar system, so these debris pieces are at least 4.5 billion years old (if not older)!

Earth’s orbit takes our planet through that material about this time every year, and those little pieces of dust and grains of sand from the comet get swept up through our atmosphere. Most of them vaporize on the way down, and thus never reach the surface of our planet. These flares are called meteors; the tiny objects that cause them are called meteoroids.

So, dress warmly, prepare to stay up a little later than usual (or get up a couple of hours before dawn), and wait for the Perseids to send a few bits of solar system history across the sky for you to enjoy!

Want to know what else is up this month? Check out Our Night Sky over at AstroCast.TV—a quick tour I take each month through the highlights of stargazing.  This month we explore the planets, the Perseids, some familiar constellations and some deep-sky objects.

 

astronomy

Zoom to Andromeda

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Pushing the Boundaries of Ground-based Observing

A chart showing how to find Andromeda (also often called the Great Andromeda Nebula) in the late night/early morning skies in August. Made using Stellarium.
A chart showing how to find Andromeda (also often called the Great Andromeda Nebula) in the late night/early morning skies in August. Made using Stellarium. Click to enlarge.

If you go out very late tonight or early in the morning, look around for the constellation Cassiopeia. It’s a W-shaped star pattern high in the northern part of the sky. Not far away from it, you might spot a little schmear of light that looks like a little oval-shaped cloud. This is the Andromeda Galaxy, which is the closest spiral galaxy to our own Milky Way. It lies about 2.5 million light-years away, so the light that you see coming from it as you view left the galaxy about the time some of our earliest ancestors were living in caves.

If you look at Andromeda (M31 for short) through a decent back-yard type telescope, you can make out a spiral galaxy, but it’s a pretty fuzzy view. And, if you could zoom the view using a professional observatory to see individual features, it would be focused on only a part of the galaxy since such a telescope would like magnify the view so much to get the features you want. As far away as M31 is, it can quickly fill a field of view as you zoom in. So, astronomers have been seeking new and better ways to image it completely and sharply from the ground, and use more sophisticated data analysis techniques to bring out individual features in M31 (and any distant object, really) while still capturing the entire scene. They want the beauty of a panoramic scene with the clarity of a close-up.

A complete view of M31 taken by HSC, which allows Subaru Telescope to observe an extremely wide field of view, equal to nine times the area of the full moon. Odd-colored regions at the edge occur because the boundary area of the image circle is hard to process and observed area does not perfectly coincide in the three bands seen by the camera. (Credit: HSC Collaboration / Kavli IPMU) (Click to get full-resolution view.)

The Subaru Telescope of the National Observatory of Japan recently took a full view of the Andromeda Galaxy using the telescope’s powerful Hyper Suprime-Cam (HSC) to try and get that high-resolution panoramic view. The data were processed through special software by scientists affiliated with Subaru, the Kavli Institute for Physics and Mathematics of the Universe, and Princeton University. The result is a spectacularly sharp view of our distant neighbor in space. If you zoom in on the full-resolution image, you can see individual stars in the galaxy, which is just amazing.

The amount of data needed to create an image of this size and clarity is quite large, and requires what’s called “pipeline” processing. As more of these high-resolution data sets stream from the world’s telescopes, such pipelines will grow and evolve. This “first light” image from the HSC-equipped Subaru Telescope shows the power of good equipment and high-end processing to bring dim, distant objects in the universe “closer” to us for study. The fact that this comes from a ground-based telescope on the summit of Mauna Kea in Hawai’i, which is well above much of Earth’s atmosphere (but still has to deal with some atmospheric interference) is really astounding.

Take some time to browse the larger image and check out some of the other images that the Subaru folk posted on their page. Let your eyes zoom to Andromeda through Subaru’s high-resolution camera, and let your imagination explore this distant stellar city.