November 28-December 8, 2013

South Bend, Indiana

ISON Doing What Comets Do

Posted by chuck // October 23, 2013 // in Comets //

When the inbound Comet ISON emerged from behind the sun at the end of summer 2013, amateur astronomers were first to capture images.  Some people insisted Comet ISON was showing signs of buy generic prednisone an early demise, while others were equally vocal that it would be a wondrous sight.  The truth, it seems, is somewhere in between.  Images from the Hubble Space Telescope (HST) suggest Comet ISON is acting like a normal comet.  It's intact and http://www.amtuae.com/levitra-mexico getting larger as it gets closer to the sun.

Advanced Amateurs

peach-damian.jpgHST and other major instruments are restricted from viewing objects near the candian viagra sun, and when the celestial target is low above the horizon, the reward does not merit the time and expense to buy discount levitra take marginal images through muddying atmosphere.  Hence, the more flexible amateur astronomers were on the front line for capturing images of Comet ISON.  Many of those images are first released on the Facebook page of the  NASA Comet ISON Observing Campaign.

During the back-and-forth about whether Comet ISON was disintegrating, level-headed astronomers insisted they were still not worried about the comet's performance.  Yes, there is only now uncertainty about what will happen to Comet ISON when it nears the viagra tablets for sale sun, but for the moment it was doing just fine.

Hubble Space Telescope

Then, in mid-October, Hubble stepped up.  In a brief window when the comet was far enough from the sun to observe, HST captured a pair of images through each of two filters.  The result: Comet ISON is indeed intact, and a subtle jet seen in the April HST image of the comet was not present in the October image of the comet.

With its October press release, the scientists at Hubblesite held a Google+ Hangout to show the new image and how they processed the raw data.  That discussion can be viewed through the Hangout or on YouTube.  There they discuss how a handful of buy generic nolvadex images from just one HST orbit are combined, artifacts removed, models applied, and colors rendered.  It's a nice inside look at what goes into converting a raw Hubble image into a public showpiece. 

You must install Adobe Flash to view this content.

Whenever a spacecraft announces it will capture a prominent image, public expectations are high that an image will be generic cialis fast shipping available for viewing immediately.  However, sufficient care must be taken by the we choice scientists to remove artifacts of the image without compromising the integrity of the image. 

In addition to the Hangout, more text and images related to buying viagra HST image processing are on ISONblog at http://hubblesite.org/hubble_discoveries/comet_ison, including:

thumb_hs-2013-42-a-xlarge_web-2.jpg
October 17, 2013
New Hubble Image of Comet ISON: Behind the Release
by Josh Sokol

hubblesite-asteroids-plus.pngOctober 14, 2013
ISON Q&A: October 14, 2013
by Tracy Vogel

 

October 23, 2013
Looking Into Hubble's New ISON Image
by Tracy Vogel

ISON-ratio-model.jpg

 

 

 

 

streaks_combined_artifacts.pngThe two-page Hubble Space Telescope: Comet ISON Intact, October 2013, summarizes processing a Hubble image of Comet ISON.  The PDF is interpreted from the Hubblesite Hangout Hubble Releases New Comet ISON Observations, hosted by Tony Darnell.  [Note: quotes in document need attribution.]


To get a sense of what the HST team is dealing with, note the features, real and artificial, in the April image (below) of Comet ISON by HST.

Hubble, ISON, and artifacts labeled

About the Author

chuck