Re: Comet thought experiment.

From: Chris L Peterson (clp_at_alumni.caltech.edu)
Date: 01/12/05 

Date: Wed, 12 Jan 2005 14:47:27 GMT

On 12 Jan 2005 18:28:48 +1050, GD <alfa@melb.something.au> wrote:

>Upfront I'll say that I dont have any of the bits of equipment required
>to try this idea, all my astrophoto stuff is film based. Not a CCD or
>laptop in sight.
>
>On the topic of comet hunting:
>It seems that there is such a thing as a "typical comet spectrum". Doing
>a google search on the topic seems to bear this idea out anyway.
>
>What I had in mind was taking a few CCD images of the same patch of sky,
>each image taken through a different filter (UHC, Swan Band etc...).
>Then a bit of software would look though the images and display a view
>based on how similar the intensities of each pixel in those images
>represented the intensities expected by a comet.

This could work in some cases, but it probably wouldn't be as efficient as you'd
like. First of all, to get good spectral resolution you would need to use fairly
narrowband filters, which means you would be throwing away a lot of light and
your individual exposures would have to be quite long. Second, it is very easy
to automate a search for movement. It is only when the comet is still very far
out that the movement is small and harder to detect, but when it is far out it
also isn't showing much secondary emission from solar radiation, and the
distinct spectrum you are looking for isn't there.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

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