rfits

[Guest]

 Dear Mr. Phillip,

Its been long time we haven't get in touch.Hope you still remember me.
I have a few questions here:
1. Why there is a big different of the pixel value of fits image and rfits image?I have made comparison between them for certain pixel, the fits image gave ~1600 ADU but the rfits image gave only ~120 ADU.Does this will affects the result of measurement analysis especially the SN ratio?

2. Following on that problem, I have changed a parameter of the rfits task : I set the scale to no. I thought the pixel value will remains the same after the conversion of rfits but totally not, infact the value has changed to negative value to ~ -30,000ADU. Why is that so? I'm getting more confusing now.what are the parameter that need to be changed?

Please help me Mr. phillip. I have to submit this analysis report by end of this month.


Thank you.Hope to here from you ASAP.

Naz.




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[phil]

Begin forwarded message:

Date: Sat, 12 Nov 2005 21:52:58 +0800 (CST)
From: Nazhatulshima Ahmad <a_naz8898@yahoo.com.sg>
To: phillip warner <pwarner@noao.edu>
Subject: rfits


Dear Mr. Phillip,

Its been long time we haven't get in touch.Hope you still remember
me. I have a few questions here:

1. Why there is a big different of the pixel value of fits image and
rfits image?I have made comparison between them for certain pixel, the
fits image gave ~1600 ADU but the rfits image gave only ~120 ADU.Does
this will affects the result of measurement analysis especially the SN
ratio?

2. Following on that problem, I have changed a parameter of the
rfits task : I set the scale to no. I thought the pixel value will
remains the same after the conversion of rfits but totally not, infact
the value has changed to negative value to ~ -30,000ADU. Why is that
so? I'm getting more confusing now.what are the parameter that need to
be changed? Please help me Mr. phillip. I have to submit this analysis
report by end of this month. Thank you.Hope to here from you ASAP. Naz.




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[zarate]

Hello;

Phil forwarded your message to me.

There are several reason as to why the data is
different
after changing some of the parameter of rfits. It might
be related to scaling but I cannot tell until I see the
file.

Could you put the file (I assume is FITS file) in the
ftp
site:
iraf.noao.edu:/pub

Do you know the range of values that you are supposed
to have?

I hope you can put the file in out pub directory. If
not
then can you do:

cl> imheader file.fits l+ u+
and send me the output

cl> listpixel file.fits[1,1:20]

Assuming that the image is 2-dimension.

Cheers
Nelson Zarate
NOAO/Iraf
On Sat, 12 Nov 2005 21:52:58 +0800 (CST)
Nazhatulshima Ahmad <a_naz8898@yahoo.com.sg> wrote:
> Dear Mr. Phillip,
>
> Its been long time we haven't get in touch.Hope you
>still remember me.
> I have a few questions here:
> 1. Why there is a big different of the pixel value of
>fits image and rfits image?I have made comparison
>between them for certain pixel, the fits image gave
>~1600 ADU but the rfits image gave only ~120 ADU.Does
> this will affects the result of measurement analysis
>especially the SN ratio?
>
> 2. Following on that problem, I have changed a
>parameter of the rfits task : I set the scale to no. I
>thought the pixel value will remains the same after the
>conversion of rfits but totally not, infact the value
>has changed to negative value to ~ -30,000ADU. Why is
>that so? I'm getting more confusing now.what are the
>parameter that need to be changed?
>
> Please help me Mr. phillip. I have to submit this
>analysis report by end of this month.
>
>
> Thank you.Hope to here from you ASAP.
>
> Naz.
>
>
>
>
>
> ---------------------------------
> Do you Yahoo!?
> New and Improved Yahoo! Mail - 1GB free storage!



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