Friday, September 2nd, Public Observing Night Tonight – Comet Garradd

Friday, September 2nd, Public Observing Night Tonight – Comet Garradd

Come out & bring the kids to enjoy the final chance before school begins to stay up late & view the heavens. If you’ve never seen a comet before here is your chance! Tonight we will be trying to find Comet Garradd, reported by Spaceweather.com to be approaching 6th magnitude naked eye visibility. It should now be visible in binoculars. I have also obtained a lazer pointer to assist us in pinpointing stars, clusters, galaxies, and constellations for easy finding by all. It doesn’t get any easier than this!

Garradd

Comet Garradd C2009/P1

Sky & Telescope Finder Charts found & printed out for viewing here.
Hope to see everyone there, at Cates Hill Park,10:30PM.

Clear Skies & Happy Star Trails!

David

9064

Breaking News! Supernova in M101

“British astronomers have announced the discovery of a supernova in
galaxy M101, which they claim is the nearest supernova of its type for
more than 40 years. The object was discovered at magnitude 17, but
it appears to be rising in brightness, and the team says that it could
become as bright as magnitude 10 within the next few days. That
would bring it well within the reach of small telescopes and even
large binoculars. Amateur astronomers with suitable instruments
should already be able to photograph the supernova, which has the
name PTF11kly. Its position is RA 14:03:05.81, Dec +54:16:25.4.
M101 is currently well placed for observation; it is in Ursa Major,
not far from the well-known stars Mizar and Alkaid/Benetnasch in the
Plough.
The supernova was first seen on August 24 at around 8 pm BST,
within the spiral arms of M101. An image taken the previous night
had shown no such object in that position. The discovery was made
from Palomar with the 48-inch Schmidt telescope, which is now operated
robotically by a team of British and American astronomers known as
the Palomar Transient Factory. The object’s spectrum shows that it
appears to be a Type 1a supernova, which occurs when a white-dwarf
star in a binary system explodes.
From Hubblesite.org

Supernova in M101

Supernova M101To find distances in space, astronomers use objects called “standard candles.” Standard candles are objects that give a certain, known amount of light. Because astronomers know how bright these objects truly are, they can measure their distance from us by analyzing how dim they appear.  For example, say you’re standing on a street evenly lined with lampposts. According to a formula known as the inverse square law, the second streetlamp will look one-fourth as bright as the first streetlamp, and the third streetlamp will look one-ninth as bright as the first streetlamp, and so on. By judging the dimness of their light, you can easily guess how far away the streetlamps are as they stretch into the distance. For short distances in space — within our galaxy or within our local group of nearby galaxies — astronomers use a type of star called a Cepheid variable as a standard candle. These young stars pulse with a brightness that tightly relates to the time between pulses. By observing the way the star pulses, astronomers can calculate its actual brightnessBut beyond the local group of galaxies, telescopes can’t make out individual stars. They can only discern large groups of stars. To measure distances to far-flung galaxies, therefore, astronomers need to find incredibly bright objects.                          So astronomers turn to exploding stars, called supernovae. Supernovae, which occur within a galaxy about every 100 years, are among the brightest events in the sky. When a star explodes, it releases so much energy that it can briefly outshine all the stars in its galaxy. In fact, we can sometimes see a supernova occur even if we can’t see its home galaxy.  To determine distances, astronomers use a certain type of exploding star called a Type Ia supernova. Type Ia supernovae occur in a binary system — two stars orbiting one another. One of the stars in the system must be a white dwarf star, the dense, carbon remains of a star that was about the size of our Sun. The other can be a giant star or even a smaller white dwarf. White dwarf stars are one of the densest forms of matter, second only to neutron stars and black holes. Just a teaspoon of matter from a white dwarf would weigh five tons. Because white dwarf stars are so dense, their gravity is particularly intense. The white dwarf will begin to pull material off its companion star, adding that matter to itself.    When the white dwarf reaches 1.4 solar masses, or about 40 percent more massive than our Sun, a nuclear chain reaction occurs, causing the white dwarf to explode. The resulting light is 5 billion times brighter than the Sun.                                                               Because the chain reaction always happens in the same way, and at the same mass, the brightness of these Type Ia supernovae are also always the same. The explosion point is known as the Chandrasekhar limit, after Subrahmanyan Chandrasekhar, the astronomer who discovered it.  To find the distance to the galaxy that contains the supernova, scientists just have to compare how bright they know the explosion should be with how bright the explosion appears. Using the inverse square law, they can compute the distance to the supernova and thus to the supernova’s home galaxy.

UPDATE:  Supernova in Messier 101 brightens Could be Binocular target in 1 week!
See The Bad Astronomer’s Blog Update !

http://blogs.discovermagazine.com/badastronomy/2011/08/25/m101-supernova-update/”

Perseid Meteor Shower

Each year, the Earth passes through the debris of a comet called the Swift-Tuttle. This debris is pulled in by earth’s gravity & burns up in our atmosphere. The friction from the heat generated by these tiny dust particles, no larger than the head of a pin or grain of sand, reaching speeds of approximately 45km per second slam into the gases that make up the earth’s atmosphere, causing them to burn up and give off light. Some particles are large enough to leave a glowing trail of ferry like dust called a “contrail”, similar in appearance to a jet trail than can last for several minutes. These meteors are burning up in our atmosphere approximately 80-100km above our heads. For the most part, we are quite safe.

The dust particles come from the comet known as Swift-Tuttle, named after the first 2 people to discover it. The comet leaves a path of debris as it continues in its orbit around the sun every 120-125 years. When earth crosses this debris trail, gravity takes over and the show begins! It is estimated that this debris is about 1000 years old.

If you were to trace back the streak of light to its starting point, you will find it “radiates” from the constellation Perseus. This is known as the “radiant”. As the earth turns into the debris trail scooping up these dust particles, much the same as a car driving into a snow storm, you will see more shooting stars after midnight until early morning, as this is when we are ploughing head-on into the thick of the storm.

The rate of falling stars varies from year to year, with the best reported in 1972. There are many differences in meteor counts tallied by different people in different places. The best meteor shower I ever experienced had an amazing peak of approximately 200 for one or 2 brief hours!

For those wanting to delve a bit deeper, meteor counts are also performed using radio signals. When the particles burn up, they excite the hydrogen gas in the atmosphere which then releases a burst of radio waves at a known frequency. A search for more information on google will serve up an endless amount of interesting information for you to peruse through.

The Perseid Meteor Shower runs from about 2 weeks before and after the main peak dates of August 10-12. So keep your eyes on the skies for what is arguably The Greatest Show Off Earth!

Written by David Wilde