[Aavso-photometry] FWHM, up to where?

[Gary Walker]

 Hello Yenal

This looks like a good light curve to me.  You are getting 10 mmag p-p which is about 3 mmag std dev.  Thats what I hope to get each night.  Most nights are not that good.  A few are better.


 


Thanks

Clear Skies
Gary Walker
Maria Mitchell Observatory
4 Vestal Street
Nantucket, Mass  02554

 


 

-----Original Message-----
From: Yenal Ogmen <yenalogmen at yahoo.com>
To: AAVSO Photometry <aavso-photometry at mira.aavso.org>
Sent: Thu, Jun 25, 2009 9:39 am
Subject: [Aavso-photometry] FWHM, up to where?











Hi all,

I just want to ask you about your experiences of different FWHM. Generally, I 
have 3-4arcsec FWHM at my site. I usually arrange my focus in such a way not to 
have FWHM less than 3arcsec. As far as I know, if you have very small FWHM, your 
loss of the star light can be big due to circumference of the pixels. Anyway, 
last night, there was breeze and the seeing was terrible. FWHM was around 
5arcsec at the beginning of the time-series when the star was at its heighest 
position. When it was almost the end of the session, FWHM exceeds 8arcsecs. But 
when I did the photometry in the morning to get the LC of the eclipsing binary, 
I got pretty good LC.(http://www.lookatcyprus.com/astronomy/yenalogmen/TZBoo.jpg). 
My question is how do our observations affected due to FWHM? Of course, it is 
obvious that SNR decreases with the increase of FWHM but its not that much as 
far as see for the relatively bright s
tars. Is there any theorical boundaries 
for FWHM for precise
 observation? I just want to hear your FWHM choices and experiences you faced.

Thank you.

 
Yenal Ögmen
Green Island Observatory (B34)
www.greenislandobservatory.com
Geçitkale
North Cyprus


      
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