COMET MACHOLZ:
COMET WATCH THURSDAY 13 JAN 2005 AT 8PM MILLENIUM STATUE, BLACKROCK
In conjunction with Astronomy Ireland I have organised a comet watch as outlined above. Depending on the viewing conditions (light polution etc) we may move to a darker area close by. The event for Friday 7th January was cancelled due to the storms which hit the area. The forecasts for this Thursday night are more promising. The comet in question is Comet Macholz (C/2004 Q2). Comet Malcholz was discovered by amateur astronomer Don Macholz from California in August 2004. It is the 10th comet that Mr Macholz has discovered. It is a long-period comet and takes thousands of years to complete a single orbit around the Sun. Bring binoculars if you have them and wrap up well!
It has been decided that any donations received at this event will be donated to the Irish Red Cross Tsunami Fund.
Time permitting I will also give a brief outline on the night sky, showing the more prominant constellations, stars, planets, man-made satellites and any other points of interest. If you live in the Co Louth area and know of people interested in attending a Comet Watch in your area, please contact me by e-mail by clicking here.
WHAT ARE COMETS? Comets are ice-rich bodies that become prominent when heat from the sun causes their trapped volatiles to sublimate. The most visible and distinctive features of comets are the coma and tail. However, most of the mass of a comet is contained within a comparatively tiny central nucleus, and it is this body that is of the highest scientific interest because of its likely identity as a planetesimal from the outer regions of the solar nebula.
MORE DETAILED DESCRIPTION: Comets are small, fragile, irregularly shaped bodies composed of a mixture of non-volatile grains and frozen gases. They have highly elliptical orbits that bring them very close to the Sun and swing them deeply into space, often beyond the orbit of Pluto.
Comet structures are diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun. Usually a small, bright nucleus (less than 10 km in diameter) is visible in the middle of the coma. The coma and the nucleus together constitute the head of the comet.
As comets approach the Sun they develop enormous tails of luminous material that extend for millions of kilometers from the head, away from the Sun. When far from the Sun, the nucleus is very cold and its material is frozen solid within the nucleus. In this state comets are sometimes referred to as a "dirty iceberg" or "dirty snowball," since over half of their material is ice. When a comet approaches within a few AU of the Sun, the surface of the nucleus begins to warm, and volatiles evaporate. The evaporated molecules boil off and carry small solid particles with them, forming the comet's coma of gas and dust.
When the nucleus is frozen, it can be seen only by reflected sunlight. However, when a coma develops, dust reflects still more sunlight, and gas in the coma absorbs ultraviolet radiation and begins to fluoresce. At about 5 AU from the Sun, fluorescence usually becomes more intense than reflected light.
As the comet absorbs ultraviolet light, chemical processes release hydrogen, which escapes the comet's gravity, and forms a hydrogen envelope. This envelope cannot be seen from Earth because its light is absorbed by our atmosphere, but it has been detected by spacecraft
WHERE TO LOOK: For those with a bit of knowledge of the night sky, you should look south towards Orion. If you follow a upwards-right diagonal path from Orion’s Belt, through Taurus and the Pleiades (don’t worry if you’re getting lost at this point, just stick to the direction from the belt), and the comet will be somewhere around there. For a more detailed map of the nightly position of the comet click here.
I have been observing the comet on clear nights from the light-polluted centre of Dundalk. With a standard pair of binoculars it looks something similar in size and brightness to the Andromeda Galaxy. It is easily visible in a 10x50 pair of binoculars, in fact, binoculars are probably the best optical device for observing this comet.
CONTACT ME By phone on 086-0806908 or on e-mail by clicking here.