ROSAT Status report #173: ROSAT NEWS No.65

[Michael Arida <arida@milkyway.gsfc.nasa.gov>]

Date: Tue, 15 Sep 1998 17:23:59 +0200
Subject: ROSAT NEWS No.65

=========================================================================
=                                                                       =
=              ROSAT NEWS No. 65     ---    15-Sep-1998                 =
=                                                                       =
=-----------------------------------------------------------------------=
=                 ROSAT Scientific Data Center at the                   =
=       Max-Planck-Institut fuer Extraterrestrische Physik (MPE)        =
=               Postfach 1603, D-85740 Garching, Germany                =
=-----------------------------------------------------------------------=
=  e-mail address:   rosat_svc@mpe.mpg.de                               =
=  ROSAT Service Area (including ROSAT Data Archive):                   =
=   www address:  http://wave.xray.mpe.mpg.de/rosat                     =
=   ftp rosat_svc.mpe-garching.mpg.de      user: anonymous              =
=   interactive account (including ROSAT Result Archive):               =
=     telnet xray.mpe-garching.mpg.de  user: xray  no password          =
=-----------------------------------------------------------------------=
=  XUV Center: GXUVDC@AIT.PHYSIK.UNI-TUEBINGEN.DE                       =
=   WFC Archive access via telnet/ftp ait.physik.uni-tuebingen.de       =
=                                user: xuv  (password: xuv_archive)     =
=   www address:  http://astro.uni-tuebingen.de/rosat.html              =
=========================================================================

Contents: SATELLITE STATUS
          AO-9 DEADLINE SHIFTED TO NOVEMBER 30, 1998
          CURRENT ROSAT TIMELINE


SATELLITE STATUS
================
Since beginning of September the ROSAT Observatory is back on nominal 
timeline using now the Wide Field Camera star tracker to guide the
onboard attitude control system. Compared to the mean behaviour before
the breakdown of the main star tracker, the observation efficiency 
during the past 2 weeks was lower by a factor of 2 due to several 
safe mode triggers. Good progress has been made to understand the 
reasons for these failures and avoid them by software to be commanded 
during the next few days. 

In a first attempt to learn about the performance of the new AMCS
configuration a preliminary attitude reconstruction has been applied 
to an HRI observation  of a bright point source. The resultant PSF was 
broader by about a factor of 2 compared to its value with the old AMCS 
configuration. It will take some time to optimize relevant filter and 
timing parameters, which should lead to better PSF results.


AO-9 DEADLINE SHIFTED TO NOVEMBER 30, 1998
==========================================
Although ROSAT is back on timeline and the expectations for enhancing
its observation efficiency have a sound basis, we have decided to shift
the deadline for AO-9 by another 2 months to November 30, 1998.

One reason is that in the meantime a backlog of observations of almost 
5 months has built up which we have to complete anyway. Furthermore, 
the delay will allow us to establish the imaging performance in the new 
mode.


CURRENT ROSAT TIMELINE
======================
The ROSAT timeline for the period 10-Aug-1998 to 21-Dec-1998 can be
accessed via URL  http://wave.xray.mpe.mpg.de/rosat/timeline

========================= end of NEWS ===================================