Early in December 2001 I found out about the Clear Sky Clock, created by Attilla Danko.  It provides the user with a prediction of some important items to allow you to plan your night's observing.  The items predicted by the Sky Clock are Cloud Coverage, Sky Transparency and Sky Darkness and of these the last two are the most useful as Cloud coverage has just ruined your night completely.  But the last two can make a break the night.  Will it be a high power night, or a low power night.

The line labeled cloud is visible-light cloud forecast. It forecasts percentage cloud cover. Dark blue is clear. Lighter shades of blue are increasing cloudiness and white is overcast.

The line labeled tran, is the transparency forecast. Here 'transparency' means just what astronomers mean by the word: the total transparency of the atmosphere from ground to space. It's calculated from the total amount of water vapor in the air. Dark blue means excellent transparency, befitting Arizona. Light blue is better than average and pale blue is worse than average.

The line labeled darkness is not a weather forecast. It shows when the sky will be dark, assuming no light pollution and a clear sky. Black is a dark

sky. Deep blue shows interference from moonlight. Light blue is full moon. The colors represent the limiting visual magnitude at the zenith. The legend row at the bottom shows the magnitude that each color represents

What is not shown by the Sky Clock is local seeing.  Surprisingly, as Transparency improves, Seeing normally worsens.  This means that the atmosphere is more turbulent causing the infamous star twinkle.   Through our high power telescopes the stars will jump around in the eyepiece, making view less than perfect. 

So what is the night to really going to be like?  With the Clear Sky Clock, and your eyes to judge seeing, you can immediately tell!  Check the Clear Sky Clock at http://www.fortworthastro.com/observe.html for the FWAS observatory conditions.  And thanks to Tom Wideman, you can check out other Clear Sky Clocks for the DFW area and the sites that TAS and FWAS members frequent.  This page can be found at: http://home.earthlink.net/~twideman/clearskyclocks.html

For a complete explanation of Transparency and Seeing please read the excellent article by Clay Sherod at http://www.weasner.com/etx/buyer-newuser-tips/seeing.html.

NASA Notes…….. By Jim Timmons

HAIL COLUMBIA! (Space shuttle)- It's time again to repair and upgrade the Hubble Space Telescope. This will be the forth such mission since the telescope was launched in 1990. The crew of seven on STS-109 will be taking the 108^th shuttle flight on the newly modified and improved shuttle Columbia. The 27^th trip for Columbia will be made with a new 'glass cockpit" which replaces mechanical instruments and uses less power. Columbia is the second shuttle to be so modified. The past two years of work on America's first shuttle included 133 upgrades and modifications.

TRIP'S OVER, GET TO WORK (Mars Odyssey)- The Mars Odyssey has started its scientific investigation of Mars. The first images from the thermal emission imaging system are slated to be released in March. The neutron spectrometer and the high-energy neutron detector have begun their search for hydrogen on Mars. Engineers will begin to examine the radiation environment device that was turned off last August when it stopped communication.