Author Topic: Field stars or noise?  (Read 2152 times)

astroboyOW

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Field stars or noise?
« on: August 17, 2012, 10:02:23 pm »
Very often images have irregular patterns of light throughout the field, and I'm wondering if these are field stars or background noise in the image--or something else.  Knowing could help in classifying galaxies' shape.  Here are a couple of examples:


ID: AHZ2000nr2
Survey reference: 20080677


ID: AHZ2000fyd
Survey reference: 20053579

Thanks,
Jeff

AlexandredOr

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Re: Field stars or noise?
« Reply #1 on: August 18, 2012, 08:46:44 am »
Noise I presume..
 :)

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NGC3314

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Re: Field stars or noise?
« Reply #2 on: August 20, 2012, 12:31:20 pm »
When so uniform across the image, noise. These galaxies are often so faint that the brightness scale has to be stretched to show their detail, and seeing noise speckles (from the finite statistics of photons detected) is one way to tell you're seeing the faintest real features in an image.

Wadjet

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Re: Field stars or noise?
« Reply #3 on: September 11, 2012, 05:42:37 am »
This is my second day playing here, so excuse me if this is a dumb question, but most of the images I'm getting today are variations on this: AGZ0001BCK

Obviously it isn't noise, but it doesn't look like a galaxy to my untutored eye, either. How should I classify them?

AlexandredOr

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Re: Field stars or noise?
« Reply #4 on: September 11, 2012, 11:18:28 am »
This is my second day playing here, so excuse me if this is a dumb question, but most of the images I'm getting today are variations on this: AGZ0001BCK

Obviously it isn't noise, but it doesn't look like a galaxy to my untutored eye, either. How should I classify them?

Welcome to the Zoo. I like your avatar.
I see in your picture 3 stars, with obviously a little problem with the colours, probably overexposed..

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Wadjet

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Re: Field stars or noise?
« Reply #5 on: September 11, 2012, 04:09:14 pm »
Quote
I see in your picture 3 stars
Okay, that's what I thought, but then I was getting so many of them I started to wonder whether the telescope was confused or I was. :) Thank you.