11/15/13: Comet ISON makes an appearance over Golden, CO

So in the last 24 hours, Comet ISON (C/2012 S1) has brightened considerably, becoming nearly naked-eye visible at a magnitude <6.0 (meaning in a dark-sky environment, one could see the coma unaided). I awoke at 4:37 AM due to Heidi getting a page (thanks New West!), and even though the forecast called for high clouds, I blearily hopped out of bed to see if I could see anything. Clear skies, time to scramble!

Given all the light pollution from Denver to the east of us, I could just barely make out a faint blurriness with binoculars. However, the comet could easily be seen using basic astrophotography techniques, and after settling on an exposure, I started capturing images. This first one shows the comet’s green glow over South Table Mountain, in the center of the image, about 20% of the way down from the top:


Comet ISON over Golden, Colorado.

Comet ISON over Golden, Colorado.

In the following image captured using a 5D MkIII + 70-200/2.8L IS, the tail of Comet ISON can clearly be seen (about a 50% crop into the center of the image):

Comet ISON over Golden, CO, 11/15/13 (closeup).

Comet ISON over Golden, CO, 11/15/13 (closeup).

We are currently in a very narrow window for viewing Comet ISON as it approaches the sun. Right now the comet spends about 90 minutes above the horizon prior to the sun obscuring it in dawn light, and every day that interval shortens until November 28, when it passes closest to the sun (it will not be viewable for the week or so prior to–or after– this). After that, the comet will get further away from the sun and rise earlier to the north, making it easier to view, due to being higher in the sky each day.

The following is a time-lapse of three sets of images taken this morning between 5:32 and 5:47 AM, and shows the star field moving across the camera’s field of view:


Lest you think the comet is not actually moving, below is an animated GIF image showing the amount the comet moved in those 17 minutes, slowly heading downward toward the sun, which was still about 11 degrees below the horizon when the second image was taken:

Animated GIF of 17 minutes of movement of Comet ISON, 11/15/13 (refresh page if image stops animating)

Stay tuned and cross your fingers that this comet doesn’t completely disintegrate before it grazes the sun on Thanksgiving Day; there are all sorts of possibilities, and currently no one knows what will happen.


One Comment

  1. Bill K November 18, 2013 at 10:03 #

    Nice job Jeff