Imaging the April Fools Comet

As we have spent most of our time the past few months planning for the big road trip to New Mexico to install the Astronomical Telescope for Educational Outreach (ATEO), I thought it would be nice to do a little remote imaging during one of our weekly ATEO planning conference calls. With all of the comets that have been observable lately, why not quickly capture an image of one remotely from one of iTelescope's remote robotic telescopes, hosted at New Mexico Skies. This remote telescope hosting facility is not too far from where Insight Observatory's ATEO telescope will be hosted just over a month from now at SkyPi Online Observatories.

Comet 41P/Tuttle-Giacobini-Kresák pictured with the star Beta Draconis (lower right).
 Image by Insight Observatory.

On the morning of Thursday, April 20, 2017, at 5:05 am EDT, I logged into iTelescope's T14 which is Takahashi FSQ Fluorite with a Petzval Apochromat Astrograph optical design for taking wide-field images. The CCD camera used to image the comet was an SBIG STL-11000M. The image is a simple combined 2 luminances at 5 minutes a piece. The comet's location was just north of the star Beta Draconis in the constellation Draco. If you zoom into the image, you will notice there are two comet nuclei. This demonstrates how much the comet moved between both five-minute images.

Comet 41P/Tuttle-Giacobini-Kresák, a comet whose identity took nearly 100 years to pin down, made its closest approach to Earth on Saturday, April 1st, just in time for April Fools' Day, but it was not a cosmic prank. It was the comet's closest Earth encounter in more than 50 years, and maybe more than a century stated NASA officials.

The comet was first discovered in 1858 by Horace Parnell Tuttle of the Harvard College Observatory, Cambridge, Massachusetts. It was then re-discovered by Michel Giacobini in 1907 and Ľubor Kresák in 1951. The comet had two close encounters with Jupiter that altered its orbit slightly. A member of the Jupiter family of comets, 41P makes a trip around the sun every 5.4 years, coming relatively close to Earth on some of those trips. On this approach, the comet will pass our planet at a distance of about 13 million miles (0.14 astronomical units), or about 55 times the distance from Earth to the moon.

As the comet passed closest to Earth (0.14 a.u.) from mid-March through early April, it continued to hurry across the circumpolar constellations Ursa Major and Draco. Created with Chris Marriott's SkyMap

"Comet hunters in the Northern Hemisphere should look for it near the constellations Draco and Ursa Major, which the Big Dipper is part of," NASA officials said in a statement. "Whether a comet will put on a good show for observers is notoriously difficult to predict, but 41P has a history of outbursts, and put on quite a display in 1973. If the comet experiences similar outbursts this time, there's a chance it could become bright enough to see with the naked eye. The comet was expected to reach perihelion, or its closest approach to the sun, on April 12." The comet should stay visible through the month of July this year.

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Comet 41P/T-G-K Slingshots Across the Big Dipper

With St. Patrick's Day this week, green naturally comes to mind. I'm usually the one chastised by my co-workers for not wearing green. Just forgetful, that's all. When it comes to comets, we know that when one starts "greening up," it's a sign that it's getting closer and brighter. Only two weeks ago, before departing the evening sky, 8th-magnitude Comet 2P/Encke glowed pale emerald in my telescope. I hated to see it go.

Comet 41P/Tuttle-Giacobini-Kresak pairs up with the beautiful spiral galaxy NGC 3198 on March 14. Chris Schur.

But as often happens, when one astronomical objects depart the scene, another takes its place. This week, periodic comet 41P/Tuttle-Giacobini-Kresak begins the best part of its 2017 apparition, dashing across the circumpolar sky and brightening as it goes. Its timing couldn't be better. It's visible almost the entire night from anywhere in the northern hemisphere, so if you play your Moon-cards right, you can see 41P/T-G-K in dark skies part of every night now through about April 8th.

That's more than 3 weeks to catch the comet! And if you're like me, living in a region prone to spring clouds, you'll need it. A week ago, the comet shone at magnitude +9.2 and appeared moderately condensed with a 7′ coma. With a magnification of 64× in my 15-inch telescope, the nuclear region was a bright pip (not quite stellar) at center. Photographs are taken a few nights ago hint at a southward coma extension which may be the start of a tail.

By March 14-15, the coma had swelled to at least 12′ across but appeared less compact and more diffuse through my scope. Apparently, I was only seeing the core. Other observers using 10x50 binoculars and modest, wide-field instruments are now reporting coma diameter estimates of at least 30′ (Full Moon size) and a magnitude closer to +8. When you attempt 41P, know that its large coma will appear more obvious in a smaller, wide-field instrument than in a larger instrument with a smaller field of view.

Read the full source article at  http://www.skyandtelescope.com/observing/comet-41pt-g-k-glows-green-for-st-paddys-day/

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