Quoting from the Sky and Telescope Updates:

Dan Green of the International Astronomical Union’s Central Bureau for Astronomical Telegrams published a long summary (Electronic Telegram No. 3731) early today. Excerpts:

The comet’s nucleus apparently disrupted near perihelion, with the comet’s head fading from perhaps a peak brightness of visual mag –2 some hours before perihelion to well below mag +1 before perihelion. M. Knight, Lowell Observatory… [adds] that the brightest feature in the coma faded steadily after perihelion from about mag 3.1 in a 95”-radius aperture when the comet first appeared from behind the SOHO coronagraph occulting disk on Nov. 28.92 to about mag 6.5 on Nov. 29.98…..

K.Battams, Naval Research Laboratory, writes that, based on the most recent LASCO C3 images (Nov. 30.912 UT) … what remains is very diffuse, largely transparent to background stars, and fading; it appears that basically a cloud of dust remains….

Z.Sekanina, Jet Propulsion Laboratory … finds that the comet’s production of dust terminated about 3 hours before perihelion…

The strong forward-scattering effect (phase angles near 120-130 deg) has tempered the rate of post-perihelion fading of the comet, but the merciless inverse-square power law of increasing heliocentric distance is necessarily the dominant factor in the comet’s forthcoming gradual disappearance…

CBET 3731 via Yahoo Groups

A post mortem by Phil Plait

From CIOC (the NASA Comet ISON Observing Campaign):

Will it be naked eye visible? When? How bright?

This is definitely the toughest question but also the most frequent. We still don’t know if it will be naked eye but based on its current brightness in the LASCO images – which is around magnitude +5 and fading – it does seem unlikely that there will be much to see in the night sky. I suspect that some of the outstanding astrophotographers around the world will be able to get something, but I doubt it will be as spectacular as before perihelion. I hope I’m wrong though.

Sky and Telescope

Sky and Telescope Updates

ISON Campaign: A Trail of Questions

Universe Today

APOD

Reports are starting to come in regarding what happened to Comet ISON C/2012 S1 after passing the perihelion of its orbit.

From @astroengine and @discovery_space: Comet ISON Barely Survives Thanksgiving Solar Roast

Update from NASA CIOC: Schrödinger’s Comet

More news and mostly images of Comet ISON C/2012 S1.

Today’s Image form @EarthSky.
Will Gater picture via @chrislintott Picture via @willgater
And Another via @chrislintott
From @SungrazerComets

From EarthSky

Comet ISON, anticipated by skywatchers for more than a year, is brightening fast just days from its fateful hairpin swing on November 28 around the broiling surface of the sun. The comet is now a greenish-white fuzzy “star” in binoculars, low in the east-southeast at the beginning of dawn. Telescopic photos are showing it with a long, ribbony tail. The comet has flared with unexpected outbursts of gas and dust three times already this month.

References

Comet ISON brightening fast as its moment of truth nearsvia @earthskyscience
Latest Light Curve
Image by Bob Lukasik from Brasstown Bald 2103-11-20
ISON Encke Movie
ISON, Encke, Mercury and Home by Karl Battams

Nice! Evernote let’s you encrypt the text in a note!

Last night we visted the Fernbank Observatory. In the course of looking at a very nice open cluster, NGC 457 I believe, in Cassiopeia, I was reminded of one of my favorites there, M103. I always called it the Christmas Tree cluster and enjoyed showing it to folks.

At the site One-Minute Astronomer oneminuteastronomer.com, Brian Ventrudo describes M103 as

…the last object in Messier’s original catalog (it was later padded to include 6 more objects). It’s also easy to find, about 1 degree northeast of Ruchbah (or delta Cass). At 8,500 light years away, it’s one of the most distant open clusters in Messier’s catalog. In a small scope, the cluster is unmistakably triangular and displays perhaps two dozen stars. The star triple star Struve 131 is the bright star at the north vertex of the cluster; you can easily resolve all three stars in Struve 131 in a scope, even at low power.

Image credit: by Margin Germano at martingermano.com.

I can now summarize my previous post up in one sentence: Android had become tiring and I find the iPhone delightful.

The new iPhone 5C arrived on Wed 2013-10-02 and I found the transition from the almost-two-year-old Android Galaxy Nexus 4.2.2 easy and painless. So far I’m happy using a new device with a fresh new interface and all that I consider essential.

I’m thinking about getting an iPhone. I know this is a shocking thought. I’ve never had an iPhone before. The only smart phones I’ve ever owned were the Android phones, starting with the G1. I currently have a Samsung Galaxy Nexus with (get out the phone, tap settings, about phone, ah…) 4.2.2. I’d been planning to get a Samsung S4 or S3. I think the HTC One is currently the best Android phone hardware out there.

The old planetarium adjoined the science hall of the museum and the center piece exhibit there was a Foucault pendulum. It was a wonderful demonstration of the rotation of the earth. The planetarium office was on the third floor and also attached to the side of the cylindrical section of the building containing the planetarium. It was my office until I moved into a brand new, below ground suite of staff offices beneath the exhibit halls. The interesting thing was that the pendulum was suspended from the ceiling of that third floor office. Yes, the room had an opening in the floor, appropriately surrounded by a rail for safety.

One of the Google Doodles for this past week was the Foucault pendulum. I looked at it a day or so after it was on the main search page. I didn’t look at any of the explanations it might have linked to, but it reminded me of trying to explain the pendulum to folks in the exhibit hall. The time it takes the pendulum to apparently rotate is a very difficult concept and I’ve been trying to think of a good way to explain it for many decades. Over the past few years, I think I finally hit upon a reasonable and understandable explanation.

Image credit: Foucault pendulum at Berry College in Rome, Georgia by Courney McGough CC BY-NC-ND 2.0. Note, this is not the particular pendulum discussed in this post.