Zodiacal light may wait until spring

I still haven't seen the Zodiacal Light, I may have to wait until the spring equinox when this elusive sight is best searched for during the evening. (As I have said before, I am not a morning astronomer.)

I have, however, seen Comet 17/P Holmes.

It is easy to see in the evening sky near Mirfak, the brightest star in the constellation Perseus. I have used the naked eye, a pair of binoculars and a telescope. All three show the light golden glow of the comet quite nicely, even through the light from the full moon and in-town light pollution.

While this comet is not as bright or showy as Hale-Bopp or Comet McNaught were, the attention-grabbing feature of 17/P Holmes for astronomers is how suddenly it appeared on the scene.

When Holmes made its closest approach to the sun earlier this year it was a barely visible 17th magnitude. That means it was difficult to see even in large telescopes. About two weeks ago it suddenly flared in brightness almost a million times. It rose to second or third magnitude which is easily visible to the human eye without any help.

Astronomers seem to think the sudden change in brightness happened because more dust is being blown off the comet by the solar wind. The reason for this sudden explosion of dust is still up for discussion.

Did another body (like an asteroid) hit it and cause a fracture to allow more of the comet's body to be exposed to sunlight and knock off more dust? What did happen is not known, and may never be known.

Comet Holmes does make for some nice viewing on these fall evenings. To the unaided eye, the comet has a definite fuzzy non-starlike appearance. In binoculars and small telescopes a brighter center is discernible. In fact, the visible "coma" of sunlight-reflecting dust (which gives the comet its yellowish color) is expanding. It now is about the same size, if not larger, than the planet Jupiter when viewed through a pair of binoculars or a small telescope.

This is not the first time the comet has undergone an outburst. The first time was in November 1892, which enabled astronomer Edwin Holmes to discover it. The circumstances are similar, a sudden brightening of an otherwise obscure astronomical object. Descriptions then of the new comet are very similar to the descriptions now of this latest outburst of cometary dust.

Comet Holmes orbits the Sun every seven years or so. It never gets very close to the Sun; in fact, at its closest it passes just inside Jupiter's orbital path -- one of the reasons the comet usually stays so faint.

To find 17/P Holmes, point your browser to this Web site:

http://www.skyandtelescope.com/community/skyblog/observingblog/10775326.html

There is some discussion, a few nice photographs and a finder chart for the comet.

How long will this outburst of brightness last? Who knows. It could be two months, two weeks or two days. Go out now and look to the northeast for Perseus and the golden glow of comet 17P/Holmes.

SKY WATCH: Tiny Mercury is a fine morning object this week. It is at its greatest elongation from the Sun on the morning of Nov. 8. Look about an hour before sunrise. Bright Spica in Virgo, the Maiden is to its right and a very thin crescent moon is to the lower right of the pair. New moon on Nov. 9. On Nov. 12 about a half-hour after sunset look in the southwestern sky for a slender crescent moon and a fleeting glimpse of close-by Jupiter. It will be one of the last times to glimpse the fading giant planet until next summer.

Next time: More astronomical blatherings.