The third BeppoSAX "e-mail news" has been sent to all SAX PIs. If you have not received it and you are interested in subscribing to this service please send an e-mail message to without subject and with the words "subscribe saxpi" as the only text.


The problems encountered by the satellite on December 11 (see bullet dated Dec 17) have now been solved. Normal science operations have been resumed.


The SAX Image Simulator now also supports the simulation of JET-X CCD images. Other missions may be supported in the near future.


At 17:30 GMT on Wednesday 11 December the satellite suffered a reset of the Attitude Control Computer which brought BeppoSAX into a completely safe full-back mode, as forseen, stopping nominal science operations.
Our investigations have shown that there is no problem in the hardware but the reason of the reset is still under investigation and we intend to recommence our normal observation activity as soon as the reason for the reset has been understood. At this moment BeppoSAX is continuing to monitor for gamma ray bursts with the PDS and WFC are being used to monitor for transient phenomena.


Distribution of FOT data to BeppoSAX guest observers will start on December 20 1996. The motivations that led to this relatively late date are explained in detail in a message from the mission director and mission scientist that has been sent to all subscribers of the BeppoSAX electronic mailing list.


Recently Beppo-SAX observations have been disturbed by an on-board contingency which has now been resolved and the normal scientific observations resumed.

On 16/10/1996 a persistent problem of syncronization between the attitude control computer and the data handling computer was detected. A software patch for the data handling computer was developed and tested to force the correct syncronization. This was sent up to the satellite on 23/10/1996. The patch was entirely successful, and after careful check-out the normal planned schedule of observation was restarted on the evening of 24/10/1996.

During contingency the observation time was not entirely lost as the NFI made background measurements and the WFC continued to monitor the Galactic Centre region and particularly GRS1915+105, the superluminal transient, which is currently active.


First results from NFI follow-up observations of the 960720 GRB field are now available on-line. IAU Circ. 6480 and MECS & LECS images .


The complete list of BeppoSAX performed observations is now avalaible at SDC. This list is reachable from the Timelines page or from the Documentation page.


The second BeppoSAX "e-mail news" has been sent to all SAX PIs. This service is provided by SDC to periodically inform the scientific community about the status of the mission and all SAX major events. If you have not received the "e-mail news" and you are interested in subscribing please send an e-mail message to without subject and with the words "subscribe saxpi" as the only text.


The official "BeppoSAX Approved Target List" document is available on-line and can be retrieved from the documentation page of our WEB service.
The document includes a) the full list of targets, b) the list of accepted proposals, and c) the list of SAX succesful PI's with full e-mail and postal addresses.


The BeppoSAX timelines for next few months are now available on-line at SAX-SDC.
The timelines of the BeppoSAX observation program are divided into a Long Term Plan (covering the next several weeks - few months) and in a more detailed Short Term Plan (focusing on the current week).


The observation timeline (including the end of SVP and AO1 programs) has been produced and frozen for the period 1 September - 31 October 1996. The timeline will soon be available on line from our web pages.
Software for SAX data analysys is mostly ready and it is currently being tested/used on SVP data at SAX SDC and at the institutes of the SAX consortium. The detailed on-line documentation is available at SDC WEB pages. Part of this documentation is being finalized and may still be subject to frequent modifications/updates.
A new tool is available on the Web at SAX SDC. It's a WWW interface to popular NED service, with transparent links to the NASA ADS.
A complete list of the observations performed by SAX until now is available here.


SAX has successfully observed the following SVP observations: Cyg Field with WFC1, Cas A, SCO X-1 and 4U1626-67 with NFI, Cen X-3 with WFC2.
The Long Term Plan for Core and Guest Observers Program targets is in preparation. This plan takes into account the new constraint on the LECS which currently is operated only when the spacecraft is above dark earth. This constraint will be relaxed somewhat in the next few weeks.


Since 30 July SAX has been performing a long observation of the Seyfert galaxy MCG 6-30-15. This observation will finish on 3 August.


SAX has successfully completed the observation of 3C273. After this SAX NFI have observed two galactic sources Cyg X-2 and Her X-1. Currently SAX is observing GX 301-2 with the WFCs.


During the past week SAX successfully observed VELA X-1 and the VIRGO Cluster with the NFI. Currently the satellite is pointing toward the bright quasar 3C273 in the framework of a simultaneous monitoring with ASCA and XTE for intercalibration purposes.


A long SVP observation of the Seyfert galaxy NGC 4151 was performed between Saturday 6 and Tuesday 9. All NFI instruments of SAX were used. At the end of the observation the SVP program was temporarily interrupted to allow the loading of improved AOCS software which is currently being tested.
The SVP will resume on 12 July with a WFC observation of the Cygnus region.


An experimental version of a SAX Image Simulator is now avalaible at SDC via Internet. This WEB simulator is intended to support SAX users in simulating fields to be observed with the imaging instruments of SAX.


SAX has performed the first observation of a cosmic source.

On saturday 22 June Cygnus X-1, a bright blackhole candidate in our galaxy, was successfully observed with all NFI instruments and WFCs of SAX. Data analysis of this observation is in progress.


The telescopes shutters have been successfully opened on saturday, June 15. The LECS's commissioning phase is going on and will finish tomorrow. The HPGSPC's commissioning phase is scheduled for June 19 and 20.


The three MECS detectors have been swithched on at their nominal settings between June 6 and June 8th. The behaviour of all MECS instruments is nominal. Since the telescopes shutters are still closed the images obtained only include local background and calibration sources. A first M2 image is available. More detailed information is available from the MECS team pages at IFCTR.


A first WFC observation was carried out succesfully. The instrument is working nominally and the background intensity is as expected. The first detector image can be retrieved here


The SAX Time Allocation Committe and Scientific Steering Committee met on May 24th to complete the selection of the SAX AO1 approved targets. The list of Guest Observers Program pointings is now available on-line together with the list of Core Program and SVP targets.


The first SAX scientific instrument was successfully switched on.
During days 29/5 - 1/6 the PDS switch-on procedure was successfully completed. This procedure was designed to switch on all the PDS subsystems, one at a time. The full switch on procedure took 22 orbits, during which the PDS was first operated at low values of HV, then at the nominal values.
The PDS Particle Monitor is on since May 22. So now are already avalaible data on the particle fluxes during passages in the South Atlantic Anomaly for more than 10 days. Data are currently being analyzed.
On saturday June 1st, PDS was switched on (all subsystems) for an entire SAX orbit (about 100 minutes). The measured background is consistent with the expected one. Data are being analyzed and in the next few days a first estimate of PDS background in coarse energy bands will be available. The high voltage verification activity on WFC will be performed 4-5th June.


Gyro 2 has been excluded from the attitude control loop. Gyro 2 has shown an anomalous sporadic increase of approx a factor of 2 in its drift rate. This gyro is still considered by the program to be functional but was substituted (by gyro 6) for reasons of security. The reasons of the drift are under investigation.
A problem of increased background during star search mode in the star trackers, during sunlight, has been found. A modification is being implemented in the software of the star trackers to remove the problem. HPGSPC and PDS collimators have been successfully unlocked.
Phase D3, PMT (HV) check out, of PDS commissioning starts on May 29 and is expected to finish on June 1.


The commissioning phase is proceeding regularly. The science instrumens HV will be switched on starting the beginning of June.


The electronics of all payload instruments have been swithched on in stand-by mode. The PDS particle monitor is also active providing first information on the in-orbit background.
AOCS activities revealed an increase of the gyro 2 drift. Currently gyro 2 has been replaced with gyro 4 in the attitude control loop.


Today SAX has been renamed "BeppoSAX" in honor of Giuseppe Occhialini


All star trackers misalignments have been calibrated. The commissioning phase continues with the tuning of the AOCS system. Payload Testing is scheduled to start early next week.


The Science Pointing Mode has been tested succesfully. Gyro's calibrations is proceeding as scheduled and will be completed tomorrow. At that point phase A and phase B of the commissioning phase will be completed.


All on-board sub-systems are working properly. The commissioning phase is continuing as planned.


The satellite is in the nominal configuration, on the nominal orbit and all sub-systems are properly performing. The Operation Control activities have been dedicated to the following main items: AOCS (Attitude & Orbit Control System) initialization in Default Pointing Mode (DPM), On Board Data Handling (OBDH) sub-system commissioning start, Telemetry Tracking & Control (TT&C) sub-system start.


After the first 31 orbits all systems work properly. Later today OCC will start the calibration of magnetometers and gyroscopes.


SAX has been successfully launched on Apr 30, 04:31 GMT, right at the beginning of the launch window.


A www page about the latest news on the SAX launch campaign has been prepared and can be accessed directly from the SAX home page.


As a result of the Announcement of Opportunity for the Guest Observers Program (AO1-2) the SDC received 123 proposals. The overbooking is about a factor 4.5. A total of 309 proposals were received for the full SAX AO-1 (Core Program and Guest Observer Program).


To facilitate proposals preparation some WWW tools have been developed/adapted at SDC. These are a WWW interface to PIMMS and to VIEWING and a WWW SAX proposal submission server. Check on the "AO1 Information" page for details.


The second part of the first SAX Announcement of Opportunity (AO1-2) has been released today. This AO is dedicated to the Guest Observers Program and to the WFC secondary time program. The deadlines for proposal submission is March 29 and June 14 respectively.


Following the decisions the TAC and the SAX Scientific Steering Committe all PI's who have submitted a Core Program proposal will receive (via e-mail) a formal communication concerning the status of their proposal(s). This e-mail will be sent at the latest simultaneously with the issue of the SAX AO for the Guest Observer Program.


The SAX Time Allocation Committee (TAC) completed the selection of the targets to be observed as part of the Core Program for the first year of operations. The list can be accessed for the SAX AO1 Browser


As a result of the first SAX Announcement of opportunity (AO1-1) 208 proposals were received. The SAX Time Allocation Committee (TAC) and the SAX Scientific Steering Committee will meet on January 25 1996 to complete the proposals selection process. The list of approved targets will be published shortly afterwards.


The second System Verification Test has been succesfully completed.


The 99999 seconds limit on the observation duration in the e-mail proposal has been removed. Proposers can now request for exposures longer than 100000 seconds.


Templates of e-mail proposals specific for the submission of NFI and WFC proposals (proposal_nfi.txt proposal_wfc.txt) are available from our anonymous ftp area.


A version of the LECS response matrix (lecs_alpha.rmf) that can be used on ALPHA/OSF machines is available from our anonymous ftp service.

New versions of the MECS response matrix and effective area are available from the SAX anonymous ftp sites.

Approved list of Science Verification Observations

System Verification tests (SVT) have been completed successfully on Sept 12 1995

Questions should be addressed to:

Maintained by L.A. Antonelli , F.Fiore & P.Giommi

Last update: July 12, 1996