From: Kathy Rages <krages...>

Date: December 18, 2006 2:29:41 PM PST

To: Mitch Gordon <mgordon...>

Cc: Mark Showalter <mshowalter...>

Subject: Last-minute update to my VGISS comments

I see you're using the standard calibration for the WA MeJ filter:

ABSOLUTE CALIBRATION NOT GOOD,SHADING CORRECTION ONLY WAS DONE

PICTURE MULTIPLIED BY 3.35 FICOR 2/02/86 VERSION

SCALE='SATURN '

I suppose this gets into philosophy, but everybody who was there now knows the standard calibration factor for that filter was about 30% low. Maybe you have a copy of the "New Calibration Factors" memo from Torrance Johnson dated 8-18-89 (i.e. Neptune encounter), which gives 4.782 for this (VGR2) filter.

So do you go with ABSOLUTE CALIBRATION NOT GOOD and a factor you know should be increased by ~50%, or do you put in a value you know is better, but is less well documented?

--

Kathy Rages Mail Stop 245-3

650-xxx-xxxx NASA Ames Research Center

650-xxx-xxxx FAX Moffett Field, CA 94035-1000

krages@...

We have added comments in ERRATA.TXT and TUTORIAL.TXT about this uncertainty. We have also added a special note to the DESCRIPTION field in the label of all 1006 affected calibrated and geomed images.