Re: Status Report for March 2003

[Tom Droege <tdroege2@earthlink.net>]

Andrew and all,

If the image is really curved, or has some fancy shape due to a luminous 
cloud or some such then I don't want to do anything to it.  A plane will 
not do much to distort the local changes in brightness.  It will help to 
remove the gradient in the sky.  I want to remove that.

Once one does aperture photometry, then if there is a bright star sitting 
in a bright cloud, then one gets the measurement wrong, as the background 
aperture gets the bright cloud, and that is wrong.

I think I am willing to live with such things.

Do you have a better suggestion?

Tom Droege

At 11:41 PM 4/4/03 +0100, Andrew Bennett wrote:
>On Tue, 01 Apr 2003 18:35:57 +0000, Tom wrote:
>
> >Andrew and all,
> >
> >Michael allows fitting a 0, 1, or 2nd order surface to the data.  I use
> >only the first order.  I think this does not bother a nice star field.
> >
> >I have looked at lots of fields.  DS9 has a feature that allows taking N-S
> >or E-W sections through the image.  The way I set up the cuts, this these
> >sections are either flat within the noise, or I throw the image away.
>
>Sorry! I just don't see how 1st or even 2nd order can
>leave a galactic plane image, replete with blobby star
>clumps and dust lanes, flat.
>
>Andrew Bennett, Avondale Vineyard