Fit Mode selected but no fit line appears

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Fit Mode selected but no fit line appears

hrmobservatory
Hi, I selected a Fit Mode of a straight line for every plot in the chart but no fit lines appear.  Even when I select the Fit mode of a Transit a line does not appear in the plot.  Please see the attached screen prints.  Could you please let me know what I am doing wrong?  Thanks.

Ed



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Re: Fit Mode selected but no fit line appears

karenacollins
Administrator
Hi Ed,

First, make sure your airmass and BJD_TDB columns are populated with
numbers in the measurements table (i.e. not NaNs). The NaNs will cause
the fit to abort.

If that is not the problem, would you be willing to send your
measurements table and plotcfg file (save both from Multi-plot Main) in
confidence to me at karenacollins jiberish at jiberish outlook jiberish
dot jiberish com (obviously remove Jiberish to form address)? I could
take a look and see what is going wrong.

Karen


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Re: Fit Mode selected but no fit line appears

hrmobservatory
Hi Karen,

I verified that both the airmass and the BJD_TDB columns are populated with numbers in the measurements file.  In the case of airmass, each row has the same number. (-1.000000) for some reason.  Nevertheless, fit lines still do not appear on the plot.  I will send you both files you requested.  Thank you for your help.

Ed
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Re: Fit Mode selected but no fit line appears

karenacollins
Administrator
Hi Ed,

Thanks for the data files. Indeed, the constant value of -1.0 in the
airmass column will cause the fit to ignore that detrend column and not
draw a line, because there is no best fit of a constant value to another
dataset (all fits are equal). If you have another valid detrend
parameter set in addition to airmass, you would have seen a fit line
regardless. In the case of your top light curve, airmass is constant,
and BJD_TDB is all NaNs, so neither column gives AIJ a valid detrend
dataset to fit.

If you calculated airmass and BJD_TDB using DP, make sure you set up the
target and observatory coordinates correctly in the DPCC panel, and
re-run DP. Also, there is a bug in the default value of the BJD_TDB fits
header name in the DP program. Follow these directions to correct the
BJD_TDB default setting:

http://astroimagej.1065399.n5.nabble.com/Calculate-BJD-TDB-in-Data-Processor-and-load-it-into-the-Multi-Aperture-measurements-table-td286.html

If you want to recalculate the airmass and BJD_TDB values without
re-running DP, follows these instructions:

http://astroimagej.1065399.n5.nabble.com/Add-new-astronomical-values-such-as-BJD-TDB-AIRMASS-etc-to-an-exisiting-measurements-table-td91.html

After you have valid airmass and BJD_TDB data columns, your fits should
work correctly.

Karen

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Re: Fit Mode selected but no fit line appears

hrmobservatory
Great!  Thanks Karen.  I really appreciate your help.  I will do as you recommend.  I am rather new to this software but I am learning all the time.

Ed
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