Interesting presentation with workflow

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Nick

Interesting presentation with workflow

Post by Nick »

This is an interesting presentation, although it stops at introducing the workflow for images.
http://www.salt.ac.za/~crawford/lecture ... graphs.pdf

Can anyone elaborate on aperture extraction?


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swisswalter
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Re: Interesting presentation with workflow

Post by swisswalter »

Hi Nick

thanks for sharing the basics


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Spectral Joe
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Re: Interesting presentation with workflow

Post by Spectral Joe »

Nick wrote:This is an interesting presentation, although it stops at introducing the workflow for images.
http://www.salt.ac.za/~crawford/lecture ... graphs.pdf

Can anyone elaborate on aperture extraction?
In "traditional" astronomical spectroscopy the spectrum of the object is only a portion of the area of the image. It is often flanked by reference spectra, sky spectra, etc. Aperture extraction simply means choosing the part of the image desired and cutting it out. An exotic name for a common function. If you use a spectrograph with a free running camera to grab a series of spectra as the Sun drifts across the slit (becoming more common all the time) you could use aperture extraction to pull out only the line of interest and reduce the size of the data file, for example.

Joe


Observing the Sun with complex optical systems since 1966, and still haven't burned, melted or damaged anything.
Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!
Nick

Re: Interesting presentation with workflow

Post by Nick »

Spectral Joe wrote:
Nick wrote:This is an interesting presentation, although it stops at introducing the workflow for images.
http://www.salt.ac.za/~crawford/lecture ... graphs.pdf

Can anyone elaborate on aperture extraction?
In "traditional" astronomical spectroscopy the spectrum of the object is only a portion of the area of the image. It is often flanked by reference spectra, sky spectra, etc. Aperture extraction simply means choosing the part of the image desired and cutting it out. An exotic name for a common function. If you use a spectrograph with a free running camera to grab a series of spectra as the Sun drifts across the slit (becoming more common all the time) you could use aperture extraction to pull out only the line of interest and reduce the size of the data file, for example.
Joe
Ahh - got it. Subframing the CCD when the slit spectra doesn't fill the image.


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