Saturday, January 26, 2008

Largest Black Hole Found

Biggest Black Hole in the Known Universe Discovered —and it’s BIG. Whatever gave birth to this monster can be real proud. The biggest black hole in the universe weighs in with a respectable mass of 18 billion Suns, and is about the size of an entire galaxy.

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Sunday, January 13, 2008

Upgraded Hubble telescope to be 90 times as powerful

Space shuttle astronauts will attempt an unprecedented in-orbit repair of key Hubble Space Telescope (HST) instruments during the servicing mission scheduled for August 2008. The repairs, along with the addition of two new instruments, will make Hubble 90 times as powerful as it was after its flawed optics were corrected in 1993.

Thursday, January 10, 2008

NASA Satellites Capture Start of New Solar Cycle

On January 4, a reversed-polarity sunspot appeared, signalling the start of Solar Cycle 24. Solar activity waxes and wanes in 11-year cycles and the previous solar cycle, Solar Cycle 23, peaked in 2000-2002 with many furious solar storms.

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Thursday, January 3, 2008

Solar Observation - How To's

One of the most interesting and my all-time favorite celestial objects is the Sun. Many star-gazers somehow miss this quite average star which is the closest star to us and the only one that we can observe in such detail. It is also one of the few celestial objects that you can observe during the day. This is one of my first pictures of the Sun:

The very first thing that you hear about solar observation is safety. As everybody already knows you can't look directly at the Sun with your naked eyes. However, as it turns out, most makeshift solar filters such as mylar, dark or smoked glass, exposed film, etc. do not offer the adequate protection from UV (Ultraviolet Rays) that can cause permanent eye damage. Do not use them! It is very important to use a properly graded astronomical filter before attempting any kind of solar observation. There are many types – just make sure you get something that is rated 'safe for astronomical use'.

The type of filter that I use is Baader Astro Solar Filter (ND-5 rated). It replaces the cap at the end of the scope tube and blocks 99.999% of all sunlight. This type of filter is easy to use and is probably the safest. However, the filter that I got despite being made the same manufacturer as the telescope (Celestron) doesn't securely lock into place. I always use masking tape to secure it just in case. A gust of wind could easily rip it of and the Sun can blind you in a splint second.

There are also filters that attach to the eyepieces by they are known to crack and will not protect your telescope. Depending on the aperture of your telescope you may actually have heat build-up inside the tube that will literally melt your instrument.

Pointing telescope at the Sun is tricky and requires some practice (remember, you can't look through the viewfinder). The method commonly used is moving the tube until you minimize it's shadow on the ground. When you achieve this the telescope will be in alignment with the Sun.

I personally think that solar observation is 'a must' for any beginner astronomer. I actually regret not trying out my telescope during the day at first. When you get your instrument out of the box for the first time it makes it A LOT easier to learn it in daylight. Everything from setup, configuration and focusing is easier with the Sun over your head. It took me about 15 minutes just to focus the telescope the first time I got it out. As it turns out, focusing on stars is a lot more difficult than I originally thought!

Pointing your telescope to a distant object in daylight allows you to practice focusing and using your scope as well as it allows you to notice any problems which are a lot more difficult to spot at night.

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Will Asteroid 2007 WD5 hit Mars?

As you reading these lines, 2007 WD5 – asteroid 50 m (160 ft) in diameter, is speeding towards Mars at over 30,000 miles an hour. There is about 4% chance of 2007 WD5 smashing into the red planer on January 30, 2008. Whether the asteroid will actually hit Mars or not is still uncertain. Unfortunately, even if it does happen, don’t expect to see celestial fireworks. The impact would not be observable from Earth and would produce an explosion equivalent to about 3 megatons of TNT. It is expected that the impact would result in a crater approximately 0.8 km (0.5 mi) in diameter.

NASA Animation showing the motion of the uncertainty region of 2007 WD5 as it approaches Mars. The thin white line is the orbit of Mars. The blue line traces the motion of the center of the uncertainty region, which is the most likely position of the asteroid. orbital data as known on December 21, 2007 (Wikipedia). More on 2007 WD5.

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Wednesday, January 2, 2008

Solar Photography - First Attempt

My first shot at solar photography was somewhat successful. I was hoping to capture stunning sun spots but there were only a couple of tiny ones to my disappointment.

Equipped with my trusted Celestron NexStar 8SE (8" SCT) and my camera (Canon EOS 400D (Digital Rebel XTi), I secured the solar filter to the scope and started taking some pictures. The type of filter that I use is Baader Astro Solar Filter (ND-5 rated). It is made by Celestron.

After getting the alignment right, I made the following photographs by using prime focus method (through the telescope) with and without f/6.3 Focal Reducer. Without the focal reducer the Sun doesn't fit in the field of view of my telescope.

The Sun, with a focal reducer. This is false color temperature (from the following shot).

The Sun, 1/4000 sec exposure. This is true color through the filter. I had to play with the exposure so that one can see the spherical shape.

This picture is without a focal reducer (as you can see - it no longer fits in the field of view). I enhanced saturation, shadows and color to bring out the spherical form. Notice two small sun spots on the right side.

This is the close up of the sun spots. I enhanced contrast and highlights. You can also see that the Sun doesn't have a smooth surface the way it appears through the filter. It is actually granular. By playing with the contrast you can see the variations in temperature (thus the brightness).
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