‘So long, farewell, auf Wiedersehen, good buy..’

Comet ISON is now officially gone, well, pretty much. The  NASA Comet ISON Observing Campaign has issued a memoriam for Comet ISON.

Here is the latest view:

 Karl Battams: It may be (almost) gone but comet ISON leaves a legacy of unprecedented data from numerous locations within the solar system! [Image credit: ESA, NASA, Annotations by Karl Battams]

ISON appears as a white smear heading up and away from the sun. ISON was not visible during its closest approach to the sun, so many scientists thought it had disintegrated, but images like this one from the ESA/NASA Solar and Heliospheric Observatory suggest that a small nucleus may be intact.
ISON Fading

Sun vs. ISON

Tomorrow, Thursday the 28th, as we prepare for Thanksgiving (and Hanukkah) a cosmic drama is set to unfold. For months, astronomers have been observing Comet ISON approach the sun, now estimated to be less than a mile wide, wondering whether the comet will survive its close encounter and re-emerge from behind the sun to become visible to the naked eye through December. You can follow this drama on line. Between 12noon and 2.30 pm (CST) tomorrow, NASA will host a Google Hangout while all eyes on the sun will watch Comet ISON make its plunge, passing perilously close (within 730,000 miles) above the sun’s surface and accelerating to 150,000 mph. Will it survive? Break up? Evaporate? Join the Google hangout to keep track of ISON’s progress!

There is already one recent video posted of ISON coming into view of one of the extended-corona imagers from NASA’s STEREO spacecraft, seen on the STEREO website.
Discernible for most of November in binoculars, ISON is probably the most scrutinized comet ever by NASA, but from the beginning of its discovery it’s also been one of the most confusing, frustrating and unpredictable objects to observe over time. I’m still betting on ISON becoming the comet of a lifetime.

Why is Comet ISON Green?…. and other updates

Great news, everyone! Astronomers world wide have confirmed that in the last day or so, ISON has increased in brightness to the point where it is visible to the naked eye. You still have to look closely, as it is still on the border of visibility. Astronomers expect the comet to brighten as it continues to approach the Sun, but no one can know for sure. Through telescopes the green color of the comet is visible.


So why is the comet green? It isn’t uncommon for comets to glow green. This is due to the presence of certain chemicals inside the comet that are released as the nucleus sublimates away into space. Most often these chemicals are cyanogen (CN) and diatomic carbon (C2). Both of these chemicals emit greenish-blue light when in a vacuum (like outer space) and exposed to large amounts of energy (which they are getting from the Sun).

Today I came across this awesome interactive website that allows you to track ISON (as well as other Solar System objects) through the sky from different points of view. I’ll be using  it to see where ISON will be over the next view weeks, it also gives you key dates and info. Click the picture below to visit the site:


Unfortunately for us here in Baton Rouge, the next few days have a lot of clouds in the forecast! There will still be time to view the comet early next week once the sky clears… Between now and November 28 the comet is approaching the Sun. From Earth it will be getting closer and closer to the horizon in the early morning sky. If you can, try and view it before Thanksgiving.  All you have to do is:

1. Wake up very early, around 5:00 AM!

2. Find a place with a clear view of the eastern horizon.


3. Find the constellation Virgo (outlined in the image above), it will be nearly due east.

4. Look for a faint fuzzy object

5. If you’re feeling up to it, bring the camera out and snap a picture. Click here for a past article about astrophotography tips, it is for a meteor shower, but similar rules apply.

6. While you’re out, don’t miss Saturn, Mercury, and Mars.

Astronomers are unsure of ISON’s fate after it’s close approach to the Sun (which will occur on Thanksgiving Day), it is possible that the Sun’s gravity will cause ISON’s nucleus to break apart. If ISON survives its close encounter with the Sun, it will be visible once again in the morning sky around December 6th. Cross your fingers for ISON’s safe passage around the Sun, and happy viewing!


Comet ISON (Credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona)

(credit: Adam Block) This new image was taken by astrophotographer Adam Block on October 8 using an SBIG STX-16803 camera with a hefty 36.8-by-36.8 millimeter CCD sensor that provides a 16.8 megapixel image, attached to the University of Arizona’s 32-inch Schulman Telescope.

ISON’s green glow may be due to the presence of carbon molecules and seems to be intact.

Comet ISON intact so far

NASA, ESA and the Hubble Heritage Team (STScI/AURA) / October 9, 2013)

A new image of the sunward plunging Comet ISON suggests that the comet is intact despite some predictions that the fragile icy nucleus might disintegrate as the Sun warms it. The comet will pass closest to the Sun on November 28.

In this NASA Hubble Space Telescope image taken on October 9, the comet’s solid nucleus is unresolved because it is so small. If the nucleus broke apart then Hubble would have likely seen evidence for multiple fragments.

Moreover, the coma or head surrounding the comet’s nucleus is symmetric and smooth. This would probably not be the case if clusters of smaller fragments were flying along. What’s more, a polar jet of dust first seen in Hubble images taken in April is no longer visible and may have turned off.

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)


Mars Express will take photos of Comet ISON’s coma, the atmosphere that surrounds ISON’s nucleus.  Also, NASA’s Mars Reconnaissance Orbiter has been tracking ISON and may be able to get a look as well through October 2nd.

These cameras were designed to shoot high-resolution photos of Mars but scientists are going to attempt to use them to catch a glimpse of ISON as it passes.  A lot depends on how bright ISON is as it gets closer to the sun.  Keep your fingers crossed….

The high-resolution imaging science experiment (HiRISE) is one of six science
instruments for NASA’s Mars Reconnaissance Orbiter.


This illustration shows comet ISON closely passing Mars on October 1, 2013. Credit: NASA