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Measuring the Size of ISON's Nucleus: Point Spread Function

3 Sep 2013, 09:00 UTC
Measuring the Size of ISON's Nucleus: Point Spread Function
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Welcome to guest poster Dr. Jian-Yang Li. Dr. Li is a research scientist at the Planetary Science Institute and a comet expert. His interests include photometry of asteroids and cometary nuclei, physical properties of cometary nuclei, and the connection between comets and asteroids. His expertise is in photometric analysis, especially from high-resolution data obtained from the ground and returned by spacecraft. He is one of the first few astronomers who applied disk-resolved photometric analysis to cometary nuclei, and found possible connections between the photometric properties and cometary activities. Dr. Li has been actively involved in Deep Impact and Dawn missions.

(If you haven't already, you might want to read Part 1: Pixelization.)

Welcome back. In my last post, I explained how we determine the size of ISON’s nucleus despite pixelization. But that’s not our only hurdle. Now let’s talk about point spread functions.

Let’s go back to our image of Rock in Landscape.

Remember that? Now let’s look at what the way that image would appear if the rock were smaller than one pixel. We’re using a single color now, because that’s how astronomical images are taken.

If one pixel = ...

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