Man has noted the passing of comets since recorded history began, often seeing them as omens of both good and evil events. Comets are amazing to watch and while we know the timing of comets and when they will appear in our heavens there are several factors that affect the visibility of a comet from any given location.
*Size Of The Comet-Your Telescope-Where To Look
Some comets are small and unimpressive and it’s a big sky when looking through a telescope. But not to worry because Space.com Sky Watching Columnist Joe Rao says there are about a dozen comets, a year, that come within view of amateur telescopes.
Many comets, such as hale Bop and Halley’s Comet, can be seen with the naked eye or just a pair of binoculars, while others are so small or distant they require a telescope for viewing. If you are planning to buy your first telescope and aren’t sure what to start with check out the article by Ed Ting at this site.
Knowing approximately, where the comet is located and what time to view it in your area can make a big difference. There are many websites dedicated to getting the word out to stargazers, just when and where to find a comet as it approaches the earth. Check one of these sites; http://www.cometchasing.skyhound.com/index.html
*The Sun Has A Large Impact
The relationship between the sun’s position and that of the comet plays a large role in our ability to see a comet. For example, sometimes we can see the moon in the middle of the day but usually we cannot. This is because the moon doesn’t have a light source of its own but rather reflects the sun’s rays making it seem to glow.
In other words, a comet, like the moon, has no light source and simply reflects the sun’s light, making it visible at times and not at others. The positions of the sun, the comet and where you are located on the earth’s surface must be aligned just right for the comet to be visible.
*Weather Conditions
Both high and low cloud cover will block your view of the heavens at night. High humidity from any source, fog and water evaporating from a large body of water will not only distort or block your view of a comet, it will cloud your telescope or binoculars.
*Air Pollution
Weather it’s smoke from a fire, smog from an industrial park or a haze caused my our carbon footprints the air is often so polluted its impact on the visibility of a comet is sad. Comets aren’t everyday happenings and the diminished views, even far from any light pollution may be the only view we will ever have of a particular comet. Try to find the highest spot you can if it is smog or smoke that is blocking the view.
*Light Pollution
If you live in an urban area, you may find it difficult to see a comet because of light pollution. Light pollution may be a glow that covers a city caused by all the lights in that city or it may be that individual lights near you are ruining the view; this is called line-of-sight pollution.
*The Comet’s Orbit And The Earth’s Tilt
A comet orbits the sun just as earth and the other planets do, however, a comet’s orbit is more elongated than circular and for this reason, it is often out of our range of sight. Halley’s Comet takes seventy-six years to complete an orbit, so we are usually only able to see it once in a lifetime.
Each comet has its own timing, just as the planets do. As the comet’s path nears earth, it becomes easier to see if conditions are right. The longer a comet’s orbit, the longer its life because each time it passes the sun it becomes smaller.
Just as the earth tilting on its axis can change the seasons, so to can it change what we are able to see in the night skies. What the northern hemisphere sees in the night sky isn’t the same as what the southern hemisphere sees, so the comet may not be in our range of viewing. The higher a comet is in our viewable sky, the easier it is to see.
As comets are constantly being discovered, and astronomers estimate that there are at least one-trillion of them, orbiting our sun, your chance of seeing one is good. Taking these factors that impact the visibility of a comet into consideration will help you to find a comet and a place to view it.
http://www.esa.int/esaMI/Rosetta/SEMSCM474OD_0.html
http://www.astronomy.com/asy/default.aspx
http://www.space.com/spacewatch/comet-hartley-2-passing-earth-101001.html
