NASA finds direct proof of dark matter by observing this cosmic collision.
The pink clumps (hot gas) are detected by Chandra X-rays and contains most of the normal and baryonic matter in the two clusters.The bullet-shaped clump on the right is the hot gas from one cluster, which passed through the hot gas from the other larger cluster during the collision. The galaxies are shown in orange and white in optical image. What are the blue clumps? What has caused this scene?
This animation helps you to understand more about the collision. Download it here. (2.92MB)
Explanation by Chandra X-ray Observatory:
The blue areas in this image show where astronomers find most of the mass in the clusters. The concentration of mass is determined using the effect of so-called gravitational lensing, where light from the distant objects is distorted by intervening matter. Most of the matter in the clusters (blue) is clearly separated from the normal matter (pink), giving direct evidence that nearly all of the matter in the clusters is dark.
The hot gas in each cluster was slowed by a drag force, similar to air resistance, during the collision. In contrast, the dark matter was not slowed by the impact because it does not interact directly with itself or the gas except through gravity. Therefore, during the collision the dark matter clumps from the two clusters moved ahead of the hot gas, producing the separation of the dark and normal matter seen in the image. If hot gas was the most massive component in the clusters, as proposed by alternative theories of gravity, such an effect would not be seen. Instead, this result shows that dark matter is required.
Published on
August 28, 2006 in
NASA.
NASA mission managers announced at a midmorning briefing today that rollback preparations are proceeding, ensuring that Space Shuttle Atlantis would be safely back in the Vehicle Assembly Building before effects from Tropical Storm Ernesto would be felt at the Kennedy Space Center on Florida’s east coast.
The next launch date has not been set.
Published on
August 26, 2006 in
NASA.
The Atlantis crew arrived at NASA’s Kennedy Space Center in Florida Thursday to begin final preparations for mission STS-115. Flying T-38 trainer jets, the astronauts landed at the Shuttle Landing Facility at 11:30 a.m. EDT. The Atlantis crew members have been trainned for 4 years and set a record! They should have done this mission more than 3 years ago but the Columbia disaster put off the mission.
They are going to install the P3/P4 integrated truss and a second set of solar arrays on the space station, doubling the station’s current ability to generate power from sunlight and adding 17.5 tons to its mass.
The Atlantis crew launches at 10.30a.m. EDT, 29 hours from now. To know more about the crew members, please kindly visit NASA.
Do you feel sad or happy about the decision? I don’t.
Both Pluto and Charon were supposed to be planets under the defination proposed on 16 August 2006. However, the IAU meeting on 24 August 2006 demoted Pluto as a dwarf planet. As the Pluto and Charon occupy the region with other objects, ie. Pluto doesn’t dominate the region like the 8 planets do.
The objects in the Solar System are categorized into 3 groups:
Planets: From Mercury to Neptune
Dwarf Planets: Pluto and any other round object that “has not cleared the neighborhood around its orbit, and is not a satellite.”
Small Solar System Bodies: All other objects orbiting the Sun.
If you are not satisfied with this decision, you may go to “Live vote: Where do you stand on Pluto”. I am not sure whether it works.
To master your imaging platform, you’ll have to know the resolution of your setup. The setup mentioned is consisted of a telescope optical tube assembly (OTA), a mount and a camera.
Let’s say, if your setup’s resolution is sub arcsec/pixel (less than 1 arcsec/pixel), you need a very stable and precise mount, usually a high end German Equatorial Mount (GEM), for this. As the resolution is higher (the lower the value of arcsec/pixel), your setup is more sensitive to vibration, atmostpheric turbulence, wind, flexure between optical tube and GEM head and the mis-polar-alignment. In a simple phrase, the margin of error is limited.
Therefore, before you start taking image, you should know the highest possible resolution of your setup so that you do not end up with a imaging resolution that exceeded the conditions allowed. Nobody likes poor quality photo. Well, let’s get into the math part.
To calculate the resolution, follow the simple formula:
Resolution (arcsecond) = [CCD Pixel Size (in micron) ÷ Focal Length (mm)] * 205
Credit to Webfoot at Cloudy Nights forum for providing this formula. 
Published on
August 22, 2006 in
Cameras.
Right: New QHY2 case
Yes, I am going to get QHY2 as an imager specially for deep sky imaging. QHY2 is designed by Dr.Qiu Hong Yun, a PhD of Precision Measurement Technology and Instrument from Beijing Tsing Hua University.
What makes me choose this over Meade DSI II? Let me reveal it when I have it in my hand. 
The CCD of QHY2 is changeable. Therefore, it’s possible for you to opt a higher sentivity monochrome CCD with filter wheel and filters. Now, I’m going to get it with the original colour CCD. It’s the ICX412, a Sony Super HAD CCD that has 3.3 mega pixels in 1/1.8″ CCD array. Its pixel size is 3.45*3.45 which is small enough to tame the short focal length telescope.
(Hey wait, mine is a long one.. Got to get a focal reducer!)
I will do a review on this imager once I have received it, the estimated arrival time is October May June 07. QHY is designing a new case. The new case is done. It’s the one at the right on the picture above.
Edited:
1. Wrong CCD version, it should be ICX412 (2X sensitive of ICX262)
2. Designation given to QHY as he is now a PhD. Congratulations! (Editted on 9 April 2007)
3. Some minors changes made.
NASA finds direct proof of dark matter by observing this cosmic collision.
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