[Aavso-photometry] HD37605 data request

[Radu Corlan]

> > a) I don't know the Kv coefficient for my location, so I cannot correct 
> > my data for first order extinction.

Jean-Luc,

One more thing: you may be able to determine the extinction coefficient 
from your data. you have to plot the instrumental magnitudes of your comp 
star againt airmass. The plot should slope down, with a slope equal to 
your extinction coeff. The only catch is to first see if the exctinction 
was stable during the time. The spread of the values around the 
downsloping line should be of the order of your total SNR (poisson plus 
scintillation). If this is the case, you can safely use the slope of the 
plot as your extinction coeff. 

Radu



> >     Is it OK to report my data without applying the extinction 
> > correction - and provide the uncorrected data with Airmass instead ?
> > 
> > b) I am not sure how to calculate Scintillation error impact on my data. 
> > I read in a previous thread that the err should be calculated as follows :
> >     err = SQRT(1/NetCountVar + 1/NetCountComp + 2*SQRT(Scintillation)).
> 
> 
> Jean-Luc,
> 
> the above should be:
> 
>      err = SQRT(1/NetCountVar + 1/NetCountComp + 2*SQR(Scintillation)).
> 
> (note sqr instead of sqrt). This gives a total contribution of 0.006 from 
> scintillation, and a total error of 0.007 (which is consistent with the 
> 0.009 standard deviation you obtained) - and i may add, a pretty good 
> figure overall.
> 
> Radu
> 
> >      If  I do so, the err which was in the 0.002 range jumps to 0.3xx 
> > ... just because of the Scintillation factor.
> >      What does it mean ? Is Scintillation of 0,004 that bad ? 
> >      Since it does not make any sense to try to detect a 0,02 gap with a 
> > 0,3x error...what error should I report  ?
> >      What is your recommendation to calculate / include scintillation 
> > error ?
> > 
> > c) A lot of things are told about about error reporting  and I am a bit 
> > confused. Is there an AAVSO recommendation to calculate error ?
> >     The CCD Manual is giving SNR and Stdev as starting points but many 
> > emails I read on this list tend to say that it is not enough.
> >      Is there a commonly agreed procedure/formula to calculate error 
> > when submitting data ?
> >     (And especially for high precision measurement like for this campaign ?)
> > 
> > Many thanks for your advices,
> > Best,
> > 
> > Jean-Luc
> > 
> > 
> > Aaron Price wrote:
> > 
> > > I was wrong about Arto's data set, it does not include the estimate
> > >ingress time if Gary's event is indeed an egress. If anyone has
> > >observations of HD 37605 anywhere from JD 2453367.2 - 2453367.4 (16:48
> > >-  21:36: UT on December 27, 2004) please submit them as soon as you
> > >can as this is when the ingress should have occured. Thanks.
> > >
> > >  
> > >
> > 
> > 
> > 
> > _______________________________________________
> > Aavso-photometry mailing list
> > Aavso-photometry at mira.aavso.org
> > http://www.aavso.org/mailman/listinfo/aavso-photometry
> > 
> 
> 

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Radu Corlan       Snail Mail: Bucuresti sect. 1, 
rcorlan at pcnet.ro  str. Argentina nr. 28, Romania

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