Changes in latest ISIS fits header - resolving power. Why?

[Robin Leadbeater]

I see the latest version of ISIS v5.5.1 no longer includes BSS-ITRP (typical resolving power) but appears to have replaced it with something called SPE_RPOW.

Is this the same thing? Why has it changed? Are these changes documented somewhere ?

Note that Thierry Lemoult's Be star candidate database no longer detects the high resolution confirmation spectra correctly
after this change.

Robin

[Malcolm Locke]

Did you get any answer to this Robin? Some of the recent spectra coming in to the SASER database are not showing an R value because of this change. I can add support for SPE_RPOW but it would be nice to know the rationale behind the change, and I think BSS_ESRP and BSS_SRPW in combination are a better choice.

Seems to be documented in the ISIS release notes http://www.astrosurf.com/buil/isis/new/release.html

Googling for SPE_RPOW shows nothing about this header other than this post and a couple of others related to ISIS, so I assume this is a proprietary ISIS header.

[Christian Buil]

ISIS calculates the resolution power on the base of the observational data themselves. The value is really indicative (accuracy is related to the type of calibration source used and the adopted calibration mode). It can vary (not easy to evaluate).

Inconsistencies appeared between BSS_ITPR value provided by ISIS and the value expected by BeSS (from the instrument card). This is not surprising.

Since BSS_ITPR field is not mandatory for BeSS spectra submission, I deleted this field for remove some alert message from BeSS during uploading spectra phase.

So, I added a proprietary keyword : SPE_RPOW. Other keywords SPE _ *** keywords are planned in the future. I recommend a compatibility with SPE_RPOW if BSS_ITPR is not présent during FITS decoding header phase.

If there is a real difficulty I can restore BSS_ITPR (+ SPE_RPOW, with BESS_ITPR = SPE_RPOW). but I do not like this (there is a real conflict between the definition of resolution power in ISIS and BeSS (measured incertitiude vs instrument card). But, not before January 6-8.

The resolution presentation is an old debate...

[Tim Lester]

Christian,

I often process my calibration spectra separately and measure the positions and widths of several non saturated lines to get the resolution and check for calibration shifts.
I then fill out BSS_ESRP and BSS_SRPW accordingly. Your boxes for these values are currently greyed out in ISIS so I have to use different software to edit the fits header.
Are these values still in general use? If they are still valid it would be nice if these boxes were opened up for edit.

Tim