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ISIS b-v values
Posted: Mon Apr 30, 2018 3:14 pm
by Robin Leadbeater
During reduction, ISIS generates b and v values for each exposure but I cannot find any information on what they are or what they are used for
- iis_b-v_values.png (5.83 KiB) Viewed 3754 times
Are they the mean intensity in the standard photometric b, v passbands?
Thanks
Robin
Re: ISIS b-v values
Posted: Sat May 12, 2018 2:02 pm
by Robin Leadbeater
Anyone ?
Re: ISIS b-v values
Posted: Sat May 12, 2018 2:15 pm
by Joan Guarro Flo
Hi Robin,
You're not alone
Yes, what and I'm, but I don't understand and I don't know the answer.
Friendly, Joan.
Re: ISIS b-v values
Posted: Mon May 14, 2018 9:20 am
by Christian Buil
Robin,
(b) - (v) information is indicative of the impact of atmospheric chromatism (or telescope chromatism) on the spectrophometric quality of the collected data in a sequence of spectra.
This situation is explained for many examples on the web page (in French sorry):
http://www.astrosurf.com/buil/dispersion/atmo.htm
(some time dramatic !)
It is an arbitrary parameter that allows to reject some very affected spectra. This is the case of spectra whose index (b) and (v) (relative intensities) deviate much from the average or median value of a sequence.
Christian B
Re: ISIS b-v values
Posted: Mon May 14, 2018 1:12 pm
by Robin Leadbeater
Thank you Christian,
This could be useful now for V392 Per which is very low. There are some big variations in the continuum of the published spectra.
Cheers
Robin