Friday, August 28, 2009

Another Iridium Flare

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I spent 5 days camping in my RV with some friends of the Astronomical Society of Kansas City at our Dark Sky Site. Located about 75 miles from Kansas City, it is far enough away from the city lights to give us amateur astronomers some really dark skies. Unbelieveably, all 5 days were clear. On one of those nights, fellow ASKC member, Eric Bogatin, said that a bright Iridium statellite was going to show up high in the eastern sky. I quickly set up my camera on a tripod and took the image you see above. When the flare was starting to brighten up, another member, Gary Pittman, pointed out where it was with his laser pointer. These laser pointers are so bright, they easily show up. The other short streak of light on the left side of the image is an airplane. For more info about Iridium flares, see my blog for Aug. 2, 2009, Iridium Flare and Extreme Numbers.


One of those 5 clear nights was on the foggy side, but that night was a super night for looking at details on Jupiter. Normally it is hard to see fine detail on Jupiter because of the turbulence in the atmosphere. All that turbulent air is also magnified by the telescope, stealing fine detail in the eyepiece. But, that foggy Saturday night, the air was perfectly still. Looking at Jupiter through a 20-inch telescope on a night like that is truely incredible. There was so much color and detail it was hard to take it all in. Jupiter's moons were seen as tiny little marbles instead of the twinkly stars I'm so used to. That night, I had three 20-inch telescopes to see it with, and their owners, Mike Sterling, Scott Kranz and Mike Meyers, were more than willing to share the fantastic view. Thanks guys for sharing the scopes. These type of night come only once in a very long time. I've only seen three nights like that in all of my 30 years of observing.

Thursday, August 13, 2009

Fishing for Persieds

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I went fishing for Perseids Tuesday night and Wednesday morning during the peak of the Perseid Meteor shower. I cast my line out 1088 times between 10 p.m and 4:38 a.m., a little over 6 hours and caught only one little flash as it went behind the trees. My fishing pole was my Canon digital XTi mounted on a tripod. Even though, on average, there was at least one meteor per minute somewhere in the sky, my little part of the sky only had one meteor bright enough to get caught.
The top picture is the first image I took and the bottom picture is #340 out of 1088.
I believe most of you know that the bright stars in the top picture make up the Big Dipper, but take a look at the second star from the end of the dipper's handle. These double stars are Mizar and Alcor. This stars are a good test for "minimal" vision. If you have good eyesight, or a good pair of glasses, you should be able to see them as separate stars. Mizar, the brighter of the two is also a double star, but you need a telescope to see Mizar's fainter companion. Astronomers tell us that the two take at least 5000 years to make their orbit about each other. What is really interesting, is that each of these two stars also has a companion, making the system a "double-double". When you add Alcor, it creates a quintuple star system. Alcor takes 750,000 years to go around the quartet of stars that make up Mizar. I wonder what it would be like to live on a planet with 5 suns in your sky?

Sunday, August 2, 2009

Iridium Flare and Extreme Numbers

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The image you see above is a 27 second exposure of the sky from my home in Cleveland, MO using my digital Canon XTi with the lens set at 18mm (the image is cropped a bit). The bright streak is an Iridium communication satellite that increased in brightness from being almost invisible to the brightest thing in the sky, other than the Moon. Traveling from left to right at roughly 17,000 mph, it increased in brightness and diminished back to near invisibility in those 27 seconds.
Non-astronomers reading this may be wondering how I knew this was going to happen. It is actuallly pretty easy. A large group Iridium satellites, traveling around polar orbits, are used to provide satellite phone and data coverage around the world. Three door-size antennas on each satellite are highly polished and occasionally, sunlight is reflected down to Earth creating a brilliant flare lasting a few seconds. Iridium Flare prediction software has been developed so that now all one has to do is log in to the website , give them your location on the Earth (latitude and longitude), and you will get a set of predictions for thenext 24 hours, the next 7 days and even daytime flares for the next 7 days. Yes, you can actuallly see them in the daytime. I've even seen some accidentally while driving down the road. Here is the predication I received to get the above image. Date: 8-1-06, Time: 11:00:43, Intensity (Mag): -7, Altitude: 27 degrees, and Azimuth: 60 degrees (ENE). That's all you need.
Terminology: Time is the period when it is at its brightest.
Intensity (Mag) is how bright it will be in Magnitude. The brightest one can get is -9 Mag. The dimmest are when they are not reflecting a spot on the Earth and that is about +6 Magnitude (about as bright as the dimmest stars one can see in a dark sky. A -7 flare like in the image is bright eneough to be seen in the daytime.
Altitude is how high it is in degrees.Azimuth is the direction to face measured from due North. North is 0 degree azimuth, East is 90 degrees, South is 180, West is 270.
I do one more thing, which is not really necessary, but to precisely know where to look, I use a planetarium program on my computer. Giving it the above parameters, it will tell me what stars and constellations will be up at that time and I can see what stars it will be near so that I can center my camera to that position.
Now for some fun with BIG numbers. There is something very interesting in this image. The camera has captured objects in great depth. In the foreground you see trees that are a mere 30 feet away. The Iridium satellite is a bit farther, about 600 miles away. The stars are even further. The star, Alpheratz, the point in the cone shape constellation of Andromeda (see the picture below), is 600 light years away. In miles, that is 3,527,175,223,910,165 miles (3.5 quadrillion miles). But the camera has captured something much, much further away. This is M31, the Andromeda Galaxy (that fuzzy spot that is quite not starlike). It is 2.5 million light years from us (146,962,495,353,380,000,000,000,000,000,000 miles [146.9 nonillion miles]). Yes, nonillion is a word. It is a 1 with 30 zeros behind it.
To find M31, I first find the curved-cone shape of the brightest stars in the constellation Andromeda, then I use the three stars connected with yellow lines to point the rest of the way. You need to be away from the light pollution of the city to find it and in a moonless sky. The camera did it, however, even with the moon out.
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