[Aavso-photometry] Peranso vs Minima V2.3 question

[Tonny Vanmunster]

Dear Yenal,

I don't know how the Kwee-van Woerden algorithm has been implemented in
MinimaV2.3. However, I was very surprised by your statement that MinimaV2.3
"always gives the same result when you change the position of the search
interval (margins)".

If you have a look at the original paper, describing Kwee-van Woerden (see
f.i. http://binaries.boulder.swri.edu/papers/kvw.html), you will notice that
the extremum, calculated by Kwee-van Woerden, is dependent on the
observations included in the search interval. So, when you change the search
interval, you should get (slightly) different results.

Based on the above, I downloaded MinimaV2.3, and loaded a test sample with
observations. When I change the search interval in MinimaV2.3, I get
different results each time. This is what I expected, but it is not in line
with your comment below. Are you sure that you have used the package in the
right way ?

Best regards,
Tonny Vanmunster


Tonny Vanmunster
CBA Belgium Observatory
http://www.cbabelgium.com 
 
PERANSO : The Light Curve and Period Analysis Software
http://www.peranso.com



-----Original Message-----
From: aavso-photometry-bounces at aavso.org
[mailto:aavso-photometry-bounces at aavso.org] On Behalf Of Yenal Ogmen
Sent: Saturday, February 14, 2009 3:47 PM
To: Aavso-photometry at mira.aavso.org
Subject: [Aavso-photometry] Peranso vs Minima V2.3 question

Hi all,

I just want to ask why I have different (~0.003 day=~5min) results of minima
of the LC for the same file and the same left and right margins used both in
MinimaV2.3 and Peranso? Both use the same algorithm: Kwee-van Woerden. ~5
min is not a small difference right? And I also observe that when you change
the positions of the margins, Minima always give the same result but on the
other hand Peranso's result changes when you change margins' position and
this change is around 0.003 days. I am surpised with this as Minima is
freeware and Peranso is not. Am I doing something wrong with Peranso?

Thank you in advance.

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


      
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