Re: Multiplot magnitude issue
Posted by chrismlt on Feb 22, 2016; 6:33pm
URL: http://astroimagej.170.s1.nabble.com/Multiplot-magnitude-issue-tp267p352.html
Karen,
Thank you for the last reply and explanations.
All is clear know.
I just have a few more questions today, and I have to submit what appears as a possible (small) issue with AIJ.
When correctly plotting lightcurves in magnitude on the graph, there's no need to airmass detrending, as airmass is self-induced by the fading of the comp stars falling to the horizon … is that correct ? Indeed, as you can see on the following plot, the uncorrected/airmass detrended lightcurve, which I draw for experimentation purpose, for comet 209P, is exactly the same uncorrected/airmass detrented.
What about the flux of the comps ? I mean : when doing a MA photometry, are the fluxes of all comps added and then the mean value of all comps used to set the value of the target, or is there a weithing of the different fluxes before adding their respective value, so that the comp stars that are brighter, are of much weight than the fainter one in the calculus.
About a possible issue with AIJ when plotting with real mag/scale, please have a look to the following images. The comps C4 (mag 12.041) should be visible on the plot, but is absent for some reason. Also you can see there a small « ? » on the C4 row, in the « then shift » column. Finally, there's some light blue dots on the bottom of the plot, which – I think – corresponds to the C4 values which are relegated there, no matter any modification I performed in the Multi-plot Y-data table.
The value of C4 appears to be ok in the measurements table.
I can send you the data if needed, please let me know what you need.
Have a nice day,
Christophe
URL: http://astroimagej.170.s1.nabble.com/Multiplot-magnitude-issue-tp267p352.html
Karen,
Thank you for the last reply and explanations.
All is clear know.
I just have a few more questions today, and I have to submit what appears as a possible (small) issue with AIJ.
When correctly plotting lightcurves in magnitude on the graph, there's no need to airmass detrending, as airmass is self-induced by the fading of the comp stars falling to the horizon … is that correct ? Indeed, as you can see on the following plot, the uncorrected/airmass detrended lightcurve, which I draw for experimentation purpose, for comet 209P, is exactly the same uncorrected/airmass detrented.
What about the flux of the comps ? I mean : when doing a MA photometry, are the fluxes of all comps added and then the mean value of all comps used to set the value of the target, or is there a weithing of the different fluxes before adding their respective value, so that the comp stars that are brighter, are of much weight than the fainter one in the calculus.
About a possible issue with AIJ when plotting with real mag/scale, please have a look to the following images. The comps C4 (mag 12.041) should be visible on the plot, but is absent for some reason. Also you can see there a small « ? » on the C4 row, in the « then shift » column. Finally, there's some light blue dots on the bottom of the plot, which – I think – corresponds to the C4 values which are relegated there, no matter any modification I performed in the Multi-plot Y-data table.
The value of C4 appears to be ok in the measurements table.
I can send you the data if needed, please let me know what you need.
Have a nice day,
Christophe
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