[b:887700b596]From: [/b:887700b596]"93249003-Hu Ruei-Hua" <d939003@mail.astro.ncu.edu.tw ([email]d939003@mail.astro.ncu.edu.tw[/email])>
[b:887700b596]Date: [/b:887700b596]November 23, 2005 9:09:18 PM MST
[b:887700b596]To: [/b:887700b596]Frank Valdes <valdes@noao.edu ([email]valdes@noao.edu[/email])>
[b:887700b596]Subject: [/b:887700b596][b:887700b596]Re: a problem about the phot[/b:887700b596]
Dear Sir,
Thank you for your reply. I've found the parameter that make the magnitudes
strange. It is the exposure time. I made a embarrassing mistake. ^^
Thank you again and have a nice day!!!
Bests,
Hu Juei-Hwa
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Open WebMail Project (
http://openwebmail.org)
---------- Original Message -----------
From: Frank Valdes <valdes@noao.edu ([email]valdes@noao.edu[/email])>
To: Hu Juei-Hwa <d939003@astro.ncu.edu.tw ([email]d939003@astro.ncu.edu.tw[/email])>
Sent: Wed, 23 Nov 2005 16:05:19 -0700
Subject: Re: a problem about the phot
[quote:887700b596]Hello,
There are a number of factors that can affect the magnitudes. These
should all be identifiable from the help description. The
magnitude depends on the zero point (obviously), the exposure time,
the area of the aperture, and the sky. The area depends on the
scale units specified. If you want me to look at your parameters
send me the result of
cl> lpar phot datapars photpars centerpars fitskypars
Yours,
Frank Valdes
On Nov 12, 2005, at 8:04 AM, Hu Juei-Hwa wrote:
[quote:887700b596]Dear Sir,
I have a problem about the output mag. values of the digiphotx
package.
Recently, I always get the mag. values larger than before in both
apphot and daophot packages. The zero point is the same before and
now.
I set the parameters follow the cookbook, A Reference Guide to the
IRAF/DAOPHOT Package, by Lindsey E. Davis,1994.
In the same image, I get ~2.5 mag. larger than before. I've checked
most of the stars in the image.
About one month ago, it happened once. I checked the parameters and
reset them. The problem was gone and I can get the "normal" mag.
values.
In these days, it happens again. After I check and reset all
parameters (I did what I did last time), the problem is still there.
I have no idea how I can get back the normal mag. values.
My OS system is Fedora Core 3. The vision of IRAF is 2.12.2.
Do you know what causes the problem? any parameters I missed to
check?? Does anyone has the problem??
Thank for your help.
Regards,
Hu Juei-Hwa
--
Hu Juei-Hwa
Institute of Astronomy,
National Central University, Taiwan
TEL +886-3-4227151 ext 65969
FAX +886-3-4262304
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