Re: question about aglc

Hi David:

thanks for your help. 
>     juan> -I'm using aglc to extract light curves
> doing:
> 
>     juan>
> a=aglc_read_events("evt2.fits","../secondary/stat1.fits");
>     juan>
> aa=aglc(a,6.6,[9.1457,9.2052],[9.1917,9.2542],"meg",[-1,1]);
>     juan>
> aglc_write_curve("lc.fits",a.fevt_1a,aa,"light
> curve");
> 
> 
>     juan> why the first row of the time column is
> different than 0.0?,
>     juan> is it possible to have the number of seconds
> since
>     juan> 2450814.5?
> 
> I offset the time to 0.0 at the start of the observation,
> just so a
> plot's time axis is easier to read by eye.  The FITS
> header keyword,
> TIMEZERO, gives the number of seconds since MJDREF.

But in my case the 1st value in the time column is different that 0 (something aroun 400 s, but depends on the observation). It should be equal to 0 if you do TSTART-TIMEZERO?. the fact that it is different than 0 means that the first photon didn't arrive when the observation started?

Thanks
-Juan



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