Comet ISON Part II: What To Expect
Saturday, November 02, 2013
Today’s Part II will serve as an ISON observing guide, noting dates, times and locations of where to look in the sky. Should Comet ISON become a very bright comet, and if it survives its very close approach to the Sun, Skyscrapers will hopefully be planning observing opportunities. (Unfortunately due to our tree-obscured northwestern horizon we will not be able to offer comet observing with our telescopes at Seagrave Memorial Observatory in North Scituate.) Keep looking for updates in this news media regarding the location(s) and observing dates and times.
The Comet ISON story began in Russia on September 21, 2012. A faint spec was discovered on images taken with a 16-inch reflector telescope as part of an asteroid search conducted by the International Scientific Optical Network, hence the name of the comet. ISON was also given an official designation of C/2012 S1.
When the orbit and distance were confirmed, it was determined to be approximately 623,000,000 miles from the Earth. Though the comet was still quite faint, original estimates suggested this dirty snowball was up to six miles across. And because it was discovered so far out, beyond Jupiter’s orbit, some astronomers started to use such descriptions like “comet of the century” and will be “brighter than a Full Moon” and “even visible in broad daylight.”
As I mentioned in my comet primer last month, comets do pretty much what they want to do. In fact, the only thing predictable about their behavior is that they are unpredictable.
ISON was initially very bright at its discovery distance because it is believed that this is the comet’s first trip towards the Sun. That means there was a lot of loose material on ISON’s surface. Solar radiation blew this material off into space, making the comet brighten.
However, after a period of time, the comet did not continue to brighten as predicted. The brightening stalled because the surface was most likely blown clean of loose material. By the time ISON got to the H2O turn-on point (where water and other volatiles react to the Sun’s heat and escape through cracks on the comet’s surface), the comet was about two magnitudes (6.3 times) fainter than forecast.
At the end of May, while Comet ISON was still out beyond the orbit of Mars, it was lost to view because it was in the direction of the Sun. When the comet finally moved out of the solar glare and was imaged on August 12, it was still fainter than what was originally forecast. At the time, some comet experts thought it was still too early to make a reliable call on what we could expect to see as ISON neared the Sun. Others simply didn’t believe it would become visible to the naked-eye. And there are those experts who do not believe Comet ISON will actually survive its close passage to the Sun.
Even as I write this column in late-October, I find it difficult to make any definitive predictions for the visibility of Comet ISON. (Remember, comets are quite unpredictable.) ISON has been visible to stargazers with telescopes using star charts or computerized pointing systems to locate the comet in the sky. In time, binoculars may eventually provide a small but recognizable image. Naked-eye views may not be afforded. Only time will tell. For now I will simply relate when and where in the sky you will have the best opportunity to catch a glimpse of Comet ISON.
While advanced amateur astronomers have been imaging ISON for some months, it is now more easily accessible to a casual stargazer with modest telescope equipment. On November 1, you can locate the comet about 22 degrees above the eastern horizon at 5:00 a.m. Don’t expect to see it with the naked-eye. The comet will be about as faint as the planet Neptune. To verify you are in the general area of the sky, you will easily see the red planet Mars residing within the constellation of Leo. ISON will be about seven degrees below and to the left of Mars. Use a wide field eyepiece and slowly scan this region. Comet ISON should display the typical comet shape with a tail of unknown length.
ISON will quicken its movement each morning as it plunges towards the horizon and a rendezvous with the Sun on November 28. At this time it is very hard to predict when the comet will be lost to view, especially since more recent brightness forecasts have ISON much fainter than originally thought. We may lose sight of it a day or two before perihelion (closest point to the Sun).
If ISON survives its close approach to the Sun (within about 700,000 miles of the solar surface), it may briefly brighten as it rises back into the morning sky to begin its journey back into the depths of the solar system. First it will appear just before sunrise very low in the east-south-east. Each morning it will climb higher into the sky and away from the Sun’s glare. Soon ISON might be seen in morning twilight, and then will rise into a darker sky. It’s merely guesswork at this point what may be seen.
Also after perihelion ISON will become visible in the evening sky right after sunset. However, during the first couple of weeks in December ISON will hang very low above the west to north-west horizon. You’ll need an unobstructed view to observe the comet. Originally astronomers were saying the tail would extend many tens of degrees into the sky. That scenario is not likely to happen. I do hope the now pessimistic predictions are wrong. If ISON ends up being a nice, not great, comet visible to the naked-eye, then we’ll all be happy.
As the weeks progress, ISON will begin to rise above the north-western horizon. By December 25, it will still be visible in telescopes as it climbs towards the north. On January 7, it will pass within two degrees (four Full Moon diameters) of Polaris, which shines at magnitude +2. The comet will be about +7 magnitude and not visible to the naked-eye. Binoculars may still show it, but it is mere speculation whether a tail will still be detectable.
After that the comet will even more quickly fade from view and memory.
Please keep in mind the above forecasts are extrapolation from known ISON facts and past comet behavior. Anything can happen.
Should new information come to light during the next few months I’ll be sure to pass them along to the various news outlets so you will have the best opportunity to view Comet ISON.
Since ISON received so much hype after it was discovered, I hope the national news services will keep everyone posted on Comet ISON updates. They can more quickly keep the general public informed should ISON’s viewing prospects change.
Keep your eyes to the skies.
Related Slideshow: Foodie Getaways in Massachusetts
Food lovers will love these destinations statewide for indulging your palate.
Vienna Historic Inn + Restaurant, Southbridge, MA
A feast for all your appetites. This historic inn is filled with old world charm, antiques, chandeliers & steins. Each room is adorned with soft music, ambience and uniqueness. You will be delighted with hard-to-find Austrian, German, Swiss, French as well local meats, seafood and vegan options. An extensive gluten-free menu available. The beer garden will be open through the end of the October.
Jewish Food Tour
Ahla Food Tours, Brookline, MA
Explore Jewish cuisine on this eye-opening 3-hour walking tour of historical Brookline and experience what TV Diner called a "fabulous Boston neighborhood tour!" and Jewish Advocate raved is "whetting the appetites of Jewish and non-Jewish diners alike". You'll taste authentic Jewish food - matzo ball soup, latkes, falafel, kosher wines, noodle kugel ice cream and dozens more. Hear unique anecdotes about the welcoming Brookline purveyors and savor the rich history of Jewish Brookline.
Blue Hills Brewery, Canton, MA
We're lucky in Massachusetts to have many microbreweries, large and small, for touring and tasting. But Blue Hills Brewery has combined its makes great tasting beers with a real educational imperative--an internship. A dream come true for beer lovers, candidates can vie for working with Blue Hills' Master Brewer Andris Veidis in a true apprenticeship. Not for the casual brewer. To learn more, check online, here. http://bluehillsbrewery.com/internship.php
Sweet Dessert Bar, Worcester, MA
A dessert lover's destination, Sweet was recently in the news for having challenged New York chef Dominique Ansel as laying claim to the invention of the cronut. Whether you're team Worcester or team NYC, enjoy Sweet's lounge chairs or sit at the bar, have a drink and watch as the chefs prepare a one of a kind dish for you. Not your average piece of cake, Sweet's appetizers and desserts are inspired by the freshest local ingredients, seasonal fruits, and artisan chocolates.
Old + New Dining
The Farm Table, Bernardston, MA
In the lush Pioneer Valley between Deerfield and the Vermont border, this remarkably restored 1800 farmhouse features cutting-edge green energy and the freshest local and regional foods seasonally available. Combine a delicious sojourn with holiday shopping at Kringle Candle and Kringle Christmas Barn.
Fried Clam Pilgrimage
Woodman's of Essex, Essex, MA
Keep summer alive year-round by making a pilgrimage to this institution that is counting down to its 100-year anniversary. Go for the fried clams, because that's what was invented here on July 3rd, 1916. Lawrence "Chubby" Woodman, at the humorous suggestion of a friend, fried up a few clams at his roadside stand in Essex, Massachusetts and the original fried clams were born.
East Dennis Oyster Farm, Cape Cod, MA
If you think oysters are a summer pleasure, you're right but you're wrong. Late October and November yield some of the best oysters, so consider bundling up and heading to the Cape for a tour of John and Stephanie Lowell's farm on the tidal flats off Quivett Neck. To make an appointment for a tour, go here.
Hit the Trail
Massachusetts Wine + Cheese Trail
A wine and cheese trail in Massachusetts? That’s right, the Bay State features 40 licensed wineries, producing wine from a collection of locally grown fruits – grapes, apples, cranberries, peaches, and blueberries – across, roughly, a total of 2,200-acres of wine farm land, where 439 acres are devoted exclusively to wine production. You can download a map and pick up the trail at any place, exploring small and pristine providers.
Wine in the City
City Wine Tours, Cambridge, MA
Want an urban oenophelia adventure? City Wine Tours is the perfect gateway to enjoying Boston's vibrant wine culture and best restaurants. Sip, savor, and explore as we take you on a walking tour through Boston's most historic neighborhoods, with stops at award-winning restaurants, luxury hotels and gourmet wine shops. Cheers.
A New Kind of Crawl
Dishcrawl Pioneer Valley, Springfield, MA
You love a pub crawl? How about a restaurant crawl? The foodies at Dishcrawl aim to provide you with Pioneer Valley's premier culinary social experience by bringing together neighborhood restaurants, local chefs, regional food producers and fellow food enthusiasts. Join for a one-of-a-kind gastronomic adventure! Check out next week's All Hallows Eve crawl in Amherst, MA.
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