Re: Transit Fitting plus referencing software in paper

Posted by David on Feb 02, 2015; 12:12pm
URL: http://astroimagej.170.s1.nabble.com/Transit-Fitting-plus-referencing-software-in-paper-tp199p242.html

Hi Karen,

A couple of additional questions. Sometimes I have had to reduce a light curve in two
sections because of the rotation of the camera which can't be taken care of by
aligning all the frames first. I notices that I can do the reduction in one go, if I also
before setting the aperture on the target and calibrators, set the position by the coordinates
that the aperture is centered on. Is there any reason to suppose that the two results may be different ?

I can see the algorithm in the first case centering itself on the centroid of the stellar image which
may be different than in the second case where the user centers the aperture on the user perceived centroid and the algorithm uses the position of the position for subsequent frames. Now throughout the
night, the centroid position may change and while the first method can takes this into account, the second method relying on coordinates cannot. This may matter for someone trying to get a transit light curve
with the highest possible precision. Am I correct here ?

In general also, if one has two telescopes observing a target simultaneously, how one combine the
light curves ? I see there is an "append" option in multi-plot so maybe this is used ?

Thanks Again,
David