The SAC-C satellite carrying the Ørsted-2 magnetometer experiment (which is essentially a copy of the Ørsted-1 boom and instrumentation) was launched on November 23 last year, and the boom has been successfully deployed on January 22. The payload commissioning phase has started; vector and scalar magnetic measurements from the CSC and SHM (Scalar Helium) magnetometers are at the moment evaluated by the team. However, we have not yet been successful in getting attitude data from the star imager, maybe due to a loose connection in a signal line. This has to be analyzed further.
However, even if it turns out that no high-precision attitude information will be available from the Ørsted-2 payload, the highly stable attitude of the SAC-C satellite (better than 1 degree) will help in obtaining magnetic vector data (though with reduced accuracy compared to Ørsted-1) in addition to the high-precision scalar data. We are working on an alternative way to obtain the attitude, too.
It is our plan to invite all Ørsted investigators to extend their research with Ørsted-2 data. We will inform you more about that when we have finished the evaluation of the first data and we know more about data quality. This will hopefully be within the next weeks. Further information is available from Per Thomsen (Ørsted-2 Project Manager, firstname.lastname@example.org) or Nils Olsen (Ørsted-2 PI, email@example.com).
After several inconclusive attempts on applying the aberrational correction to the Star Imager attitude data we now feel confident, that this correction is properly applied. The correction accounts for as much as 20-25 arc-seconds, however much of this correction was previously being compensated by the in-flight calibration of the rotation from the CSC vector magnetometer to the SIM star imager.
The calibration of the CSC vector magnetometer has also been changed according to the OVH internal frequency calibration and now accommodates a much larger temperature span than was previously used (see also Ørsted Newsletter #2). In all, the vector components has been changed by up to 7 nT.
The MAG-R and MAG-L data files have been updated in three rounds. First, MAG-R files were generated January 24, 2001. The MAG-L data up to January 24, 2000 were generated January 30, 2001, and the MAG-L data after January 24, 2000 were generated today, March 1, 2001.
We have made a preliminary change of the frequency calibration of the OVH scalar magnetometer data after July 15, 2000. The existing CSC vector magnetometer calibration has been verified to be in accordance with the changed OVH calibration. When more data become available we will make a final OVH calibration for data after July 15, 2000, however we do not expect this to deviate more than a few ppm from the current calibration. This latest calibration deviates as much as 20-30 ppm from its predecessor due to large temperature changes as we went from full sunlit into partly shadowed orbit in November 2000.
MAG-F files generated after February 18, 2001 uses the new, preliminary OVH calibration.
Further, we have cleaned out some outliers on the following days: