apall sky/ background parameters

milena wrote on Apr 04, 2011

hey,

I need the total number of counts per pixel from the background/ sky (for the "ccd equation") that IRAF calculated in apall. is it written in the database? which number is it?

thanks a lot!

milena

ps: here is the database entry:

# Wed 12:25:38 30-Mar-2011
begin aperture obj00123 1 382. 230.9466
image obj00123
aperture 1
beam 1
center 382. 230.9466
low -381. -30.
high 383. 30.
background
xmin -50.
xmax 50.
function chebyshev
order 1
sample -50:-40,40:50
naverage -100
niterate 0
low_reject 3.
high_reject 3.
grow 0.
axis 2
curve 6
2.
2.
2.
762.
-0.01559051
-1.057038

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Francisco Valdes wrote on Apr 04, 2011

I am not clear on what your goal is. The counts in the sky are not something that is output. The way I would do it, if I am understanding your request, is do an extraction with and without background subtraction. Then the difference of the two spectra will be the sky spectrum.

I hope a late reply is useful.

Frank Valdes

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milena wrote on Apr 04, 2011

thank you :)

I will try this :)

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Last post on Apr 04, 2011