Sunday, October 28, 2007

Comet Viewing

Comet 17P/Holmes recently brightened by a factor of about one
million, and is now easily visible as a bright star in the constellation
Perseus. If you look at it through even low-powered binoculars you
can make out its distinctly non-starlike appearance as a central bright
concentration surrounded by a diffuse but bright disk.

This comet currenly has no tail, but the disk of presumably recently
ejected material is growing larger by the night. At least, that's what
fellow bloggers report. Last night was the first clear night in Maryland
since the explosive brightening was reported on October 24.

If you know how to find Cassiopea (the big W), go perpendicularly
down to from the leftmost line segment of the W. You will then easily
see a triangle of stars, even if it is hazy. Even with a bright nearly full
moon nearby. Even right next to an annoying streetlight. The top star
in the triangle is Mirfak. The lower left "star" is the comet.

This page has wonderful finding charts and a plot of the observed
comet brightness as a function of time. According to the data there,
comet 17P/Holmes will be sitting in nearly the same place for many
weeks. And if predictions are to be made from recent brightness
estimates, it should stay bright for a while too. The comet had its
closest approach with the Sun in May, but the Earth is about to
catch up with, and overtake it in its orbit, giving us our closest
approach to the comet in early November.

Nights in Maryland this October are for the most part unusually
warm and calm. The comet is visible in the night sky soon after
sunset and stays an easily observable sky object for pretty much the
entire span of darkness in the night, so it is quite easy to catch a glimpse
of it, no matter what time is convenient for you to look. So, no excuses.
Go look at it!!! Tonight, tomorrow night, and whenever you think
of it.

If you are old, like me, you will remember years of cometary nothingness
when even the return of the famous Halley's comet was a complete flop.
Things started turning around for us in the early nineties with the amazing
shows of Hyakutake and the impact of Hale-Bopp with Jupiter. My South
American friend tells me that comet McNaught was quite something this
past January. So perhaps youngsters will take these times of cometary
plenty for granted. Don't. Go outside and see this one while you can. No
one can really predict when it will fade into its former next-to-nothingness
again. It is worth buying a pair of binoculars for!

2 comments:

Anonymous said...

Okay, very dumb question from a girl who is very much not a rocket scientist: Will we be able to see it from here in the southern hemisphere as well?

If so, where do we look?

The amazing thing about being back in Africa is that we can see stars at night, even in a bustling city like Cape Town!

I miss you, girl.

Creatific said...

Hi Reddi,

You'll need to be up at 1 or 2 AM but I know you are a night owl. According to the South African Astronomical Society blog:

"[28 October 2007] Comet 17P/Holmes reported visible with naked-eye from Southern African latitudes. Even with bright moon above comet it was easily seen. Though it looks like a star with the naked eye, an eerie picture awaits the observer when looking through binoculars or a telescope. Best time: 1h00 to 2h00 in the morning. Situated very low above northern horizon in Perseus. "

Miss you too!! How's Spring.Summer on your side of the planet? Here it is getting pretty frosty at night and in the mornings. Brrr.