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Vol 6, No. 5                 31 May 1996                    ISSN 1065-3597
	  (C) 1996, Regents of the University of California
Precedence: bulk

Notes from the Editor
   by Brett A. Stroozas, ISO Manager

   Welcome to the electronic newsletter for NASA's Extreme Ultraviolet
Explorer (EUVE) satellite, compiled and published monthly by the
Center for EUV Astrophysics (CEA) at the University of California,
Berkeley (UCB).  The contents of this issue of the EUVE electronic
newsletter are as follows:

 1. EUVE Science News
    1.1 Recent EUVE Science Highlights
    1.2 Abstracts of Recently *Accepted* EUVE Papers
 2. EUVE Science Operations News
    2.1 Goals/Status for the "Outsourced" EUVE Mission
    2.2 Public Data Release for 1 Jun 1996
    2.3 On-Line Access to EUVE
 3. SelMon Test-Bed Experiment to Begin at GSFC

To comment on or make suggestions for the EUVE electronic newsletter,
please send e-mail to (Internet).

   The EUVE observatory performed well throughout the month of Apr
1996, conducting observations of the following Guest Observer (GO)
targets (alternate name and spectral type information taken from the
SIMBAD or internal CEA databases; "NOIDs" are unidentified objects):

    Target          Alternate     Spectral       Observation
     Name             Name          Type         GMT Date(s)     Notes

    RE J1746-703     EUVE J1746-706  NOID    27 Mar - 05 Apr 1996  ---
    3C 273           PKS 1226+02     QSO     27 Mar - 05 Apr 1996  RAP
    1219+044         --------        AGN     27 Mar - 05 Apr 1996  RAP
    1227+024         --------        AGN     27 Mar - 05 Apr 1996  RAP
    EUVE J0729-388   --------        NOID    05 Apr - 11 Apr 1996  ---
    ALEXIS Transient --------        NOID    11 Apr - 11 Apr 1996  TOO
    EUVE J0729-388   --------        NOID    11 Apr - 14 Apr 1996  ---
    Jupiter          --------        SolSys  14 Apr - 17 Apr 1996  ---
    Mkn 421          UGC 6132        BLLac   17 Apr - 30 Apr 1996  ---
    EUVE J1429-38.0  --------        NOID    17 Apr - 30 Apr 1996  RAP
    EUVE J1434-36.3  --------        NOID    17 Apr - 30 Apr 1996  RAP
    V824 Ara         HD 155555       K1Vp    30 Apr - 03 May 1996  ---
   Key to Notes:
	RAP = simultaneous Right Angle Program imaging observation
	TOO = Target of Opportunity

1. EUVE Science News

1.1 Recent EUVE Science Highlights
	by Dr. Pierre Chayer, EUVE/CEA Scientist

  *** EUVE Observations of the Bright Comet B2 1996 (Hyakutake) ***

   Comet B2 1996 (Hyakutake), first detected January 30th by Yuji
Hyakutake in Japan, was observed by EUVE from 21-25 Mar 1996.  The
EUVE operations team successfully programmed the satellite to track
the fast-moving comet at the time of its nearest approach to the
Earth.  Concurrent with the 82 ksec spectrometer observation, an image
of the comet was obtained with the Deep Survey imaging telescope using
the Lexan filter (70-190 A).  If detected, spectral resonance lines of
helium and neon, which are only visible in the EUV spectrum, can
provide important clues to our understanding of the formation of
comets and of the solar system.  These comet observations are being
analyzed by Dr. Michael Mumma.

1.2 Abstracts of Recently *Accepted* EUVE Papers

   Included below are abstracts of EUVE-related papers recently
*accepted* for publication.  For those papers authored by CEA
personnel, the CEA publication numbers are indicated.  Unless
otherwise noted, researchers may obtain preprints of the CEA papers by
sending an e-mail request containing the publication number(s) of
interest to

   Researchers are encouraged to contribute *accepted* EUVE-related
abstracts for inclusion in future editions of this newsletter;
abstracts or preprints will also be posted under the CEA WWW Home
Page.  Please send all abstracts or preprints to


M. Abbott, W. Boyd, P. Jelinsky, C. Christian, A. Miller-Bagwell, M.
  Lampton, R.F. Malina., and J.V. Vallerga
To appear in The Astrophysical Journal (Supplement).  [CEA publication

   We describe the wavelength calibration of the Extreme Ultraviolet
Explorer (EUVE) spectrometers and measurements of the spectrometers'
resolution.  The three spectrometers operate in the wavelength range
from 70 to 760 A with a resolving power of ~300.  We present the
equations required to map each detected photon to a wavelength and
imaging angle. The equations depend on the position of the source on
the sky, the orientation of the spacecraft when the photon arrives,
and the position on the EUVE detectors where the photon arrives.
These equations were determined using a ray-traced model of the EUVE
spectrometers along with measurements of emission lines and continua
obtained both in prelaunch laboratory calibration and from
observations of stellar sources while in orbit.
   We describe the procedures used to apply the equations in this
paper to actual spectrometer data.  We also discuss the implications
of the results of this calibration for the analysis of the spectral
images and suggest aperture sizes for spectral extraction.
   With this calibration, we can remap detected photons with rms
errors of 0.22 resolution elements (0.11 A) in the short wavelength
(SW) spectrometer, 0.13 elements (0.13 A) in the medium wavelength
(MW) spectrometer, and 0.13 elements (0.25 A) in the long wavelength
(LW) spectrometer.  The imaging angles for any one observation have
rms errors of 4.8" (1.1 pixel) in the SW spectrometer, 3.3" (0.7
pixel) in the MW spectrometer, and 2.9" (0.6 pixel) in the LW


D.J. Christian, S. Vennes, J.R. Thorstensen, and M. Mathioudakis
To appear in The Astronomical Journal.  [CEA publication #735]

   We present X-ray, ultraviolet, and optical observations of the
mysterious EUV/soft X-ray source EUVE J0356-366 (= MS0354.6-3650).
Initial Einstein observations identified this source with a cluster of
galaxies, but the relatively high source count rate in the Extreme
Ultraviolet Explorer (EUVE) 100 A band and the lack of variability
hinted that EUVE J0356-366 might be a white dwarf; the UK Schmidt
plate of the field surrounding this object found a 12.45 magnitude G2V
star that could hide a compact companion. This hypothesis was
confirmed in an IUE ultraviolet spectrum that shows the definite
signature of a hydrogen-rich white dwarf (DA). A model atmosphere
analysis shows that the DA star is hot (T_eff >= 52,000 K) and may
have a low abundance of heavy elements. We show that the G2V star and
the DA star form a physical pair at a distance of 400 pc and therefore
add to the list of white dwarf plus luminous main sequence star
binaries discovered in EUV surveys.

S. Vennes and J.R. Thorstensen
To appear in The Astronomical Journal.  [CEA publication #737]

   We present H-alpha radial velocities and equivalent widths of the
hot white dwarf plus red dwarf binary EUVE J0720-317, which cover a
621 day baseline without cycle-count ambiguities and define an orbital
period of 1.26245 +/- 0.00004 d.  The equivalent width variation lags
the radial velocity by 0.21 +/- 0.02, consistent with an expected
0.25-cycle offset if the emission arises entirely from reprocessing of
the white dwarf's EUV radiation in the red dwarf upper atmosphere.
Moreover, using our new ephemeris we show that photometric variations
reported in the literature are strictly in phase with the Balmer line
strength variations, providing further support for the
EUV-illumination model.  We present revised estimates of the component
masses and discuss the binary evolutionary status.


D. Christian, J.J. Drake, R.J. Patterer, P.W. Vedder, and S. Bowyer
To appear in The Astronomical Journal.  [CEA publication #740]

   We report on observations of the eclipsing RS CVn system AR Lac
with the Extreme Ultraviolet Explorer (EUVE) scanning and deep survey
(DS) telescopes. This system consists of a G2IV star and a K0IV star
separated by 9.2 R_solar with an orbital period of about 1.98 days.
The scanner observations consisted of a single pointing over a period
of 25 hours, providing some coverage of both primary and secondary
eclipses and subsequent scanning during the all-sky survey.  During
the pointed observation AR Lac was detected in the EUVE Lexan/boron
(Lexan/B, 50-180 A) and Al/Ti/C (160-240 A) bands at average count
rates of 0.12 and 0.016 count/s, respectively.  During primary
eclipse, the Lexan/B count rate was at about one-third of its
subsequent value at quadrature, suggesting that, in the case of a
compact and relatively homogeneous corona, a minimum of 60-70% of the
extreme ultraviolet (EUV) emission originates on the G star. There was
no detectable modulation corresponding to secondary eclipse in either
Lexan/B or Al/Ti/C bands.  Data taken several months later during the
EUVE all-sky survey yield the same Lexan/B count rate as the pointed
data but only an upper limit in the Al/Ti/C bandpass.  AR Lac was
observed again with the DS as part of a Guest Observer pointed
observation.  This single pointing lasted slightly more than 3 days
and included both primary and secondary eclipses.  AR Lac was detected
in the DS Lexan/B band with an average count rate of 0.31 count/s.
The primary eclipse is easily visible as a ~40% decrease in intensity.
A dip in the lightcurve is present at the time of secondary eclipse
but is not readily discernible from the average level of variability.
A flare corresponding to a factor of two increase over the quiescent
emission count rate was observed during the next expected secondary
eclipse.  We have performed an elementary emission measure analysis
and compared isothermal models that fit the EUVE data to earlier
EINSTEIN, EXOSAT, ASCA and ROSAT two-temperature models culled from
the literature.  In general, the EUVE data indicate very similar
emission measures to those derived in previous work, indicating that
the corona of AR Lac does not vary in average X-ray or EUV luminosity
over periods of years up to a decade.  Assuming an isothermal model
with T ~ 1E+07 K, as indicated by the emission measure analysis, the
total Lexan/B count rate at quadrature implies an EUV luminosity of
1.1E+30 erg/s in the 50-180 A bandpass.


2. EUVE Science Operations News

2.1 Goals/Status for the "Outsourced" EUVE Mission
	by Dr. Roger Malina, CEA Director

   As reported in a previous edition of the newsletter, NASA has made
a decision to outsource operations of the EUVE satellite to CEA at
UCB.  In making this decision, Dr. Wes Huntress situated it within the
NASA Zero-Base Review of 1995 that stated "the guideline to NASA
centers that outsourcing and commercial services shall be maximized".
Discussions with Dr. Joseph Rothenberg, Director of GSFC, confirms
that it is GSFC's plan to outsource operations of most small
satellites such as EUVE and that discussions are already under way on
outsourcing of other GSFC missions.

   Subsequent to the outsourcing decision, the following specific
policy goals for the outsourcing were established by the EUVE Program
Manager, Dr. Guenter Riegler, in cooperation with Dr. Rothenberg and

 (1) EUVE mission operations should transition to a location at or
     near the UCB campus in order to enable student participation and
     to approximate the likely setting for future university-run
     mission operations models.

 (2) After transition of mission technical and operations knowledge
     and establishment of a robust core operations capability, an
     education component should be attached to EUVE mission operations
     in order to foster science and engineering training and outreach.

 (3) Technology innovation, testbedding, and dissemination shall
     continue to be an important objective for the EUVE program. The
     focal point at GSFC will continue to be Dr. Peter Hughes, who
     will keep the UCB team informed of technology advancements within
     NASA and will assist in disseminating technical and operations
     developments generated within the EUVE team.

 (4) After successful completion of the outsourcing transition,
     leadership and responsibility for the continued operation of EUVE
     shall transfer from NASA to UCB.

We are currently working to establish detailed plans to allow us to
meet these goals.

   The UCB proposal to NASA for the EUVE outsourcing contemplates the
establishment of an EUVE Advisory Board that would oversee policy
aspects of the EUVE operations and ensure that the interests of the
user communities are being met in the operations of the EUVE mission.
This Advisory Board is in the process of being established.

   The outsourcing schedule is a tight one, with the first phase of
transfer occurring on 16 Jul with a contract in place with an
Industrial Partner for the EUVE outsourced operations.  During the
transition there may be small impacts on the EUVE science plan; guest
observers with any concerns about any impact on their science
observations should feel free to contact me at

2.2 Public Data Release for 1 Jun 1996
        by Dr. Nahide Craig, EUVE User Support Scientist

   The table below lists the GO observations that become public on 1
Jun 1996.  For each entry is given the target name, the approximate
exposure time in ksec, the GMT start and end date(s) for the
observation, the spectral type of the target, and the data
identification code.  All public data sets can be ordered from the
archive via WWW and electronic or postal mail (see addresses below).
Please be sure to include in your order the DataID(s) of interest.
Processed data sets are shipped on 8mm tape (or, if requested, on
CD-ROM) via postal mail.

   The data rights policy for GO observations states that GOs have
proprietary rights to the data for one year from the date (s)he
receives it.  It is often the case that long observations are broken
up over many months; e.g., an observation approved for 60 ksec may
actually be observed for 10 ksec one month, 20 ksec the next and 30
ksec three months later.  In such cases the one-year proprietary
period begins after the GO is sent the final piece of the completed

      Target        ~Exp     Observation Date(s)     SpT      DataID
       Name        (ksec)    Start           End

     Data Sets Available 1 Jun 1996:

     VW Cep          100    30 Jan - 02 Feb 1995     K0Vvar   go0293   
     VW Cep           41    02 Feb - 04 Feb 1995     K0Vvar   go0294 
     kappa Cet       100    13 Oct - 17 Oct 1994     G5Vvar   go0295 
     kappa Cet        41    17 Oct - 18 Oct 1994     G5Vvar   go0296 
     EUVE J0715-704  100    09 Feb - 12 Feb 1995     DA       go0297 
     EUVE J0715-704    1    12 Feb - 12 Feb 1995     DA       go0298 
     DH Leo          100    12 Feb - 16 Feb 1995     K0V      go0299 
     DH Leo          100    16 Feb - 19 Feb 1995     KOV      go0300 
     DH Leo           21    19 Feb - 20 Feb 1995     KOV      go0301 
     HZ 43            33    07 Feb - 09 Feb 1995     DAw      go0302 
     Jupiter          56    07 May - 09 May 1994     SolSys   go0303 *
     Jupiter          82    19 Mar - 22 Mar 1995     SolSys   go0304
     AM Her          100    08 Mar - 12 Mar 1995     CV:AM    go0305
     AM Her           28    12 Mar - 13 Mar 1995     CV:AM    go0306 
     GJ 411          100    22 Mar - 26 Mar 1995     M2V      go0307 
     GJ 411          100    26 Mar - 29 Mar 1995     M2V      go0308 
     GJ 411          100    29 Mar - 02 Apr 1995     M2V      go0309 
     GJ 411           71    02 Apr - 04 Apr 1995     M2V      go0310 
     alpha Col        89    05 Mar - 08 Mar 1995     B7IVe    go0311
     EUVE J1126+186  100    13 Mar - 16 Mar 1995     DAw      go0312 
     EUVE J1126+186   81    16 Mar - 19 Mar 1995     DAw      go0313 
     UZ For           90    18 Nov - 22 Nov 1993     CV:AM    go0314 
     UZ For          107    15 Nov - 19 Nov 1995     CV:AM    go0315 
     RE 1149+28      100    26 Dec   29 Dec 1994     CV:AM    go0316 
     RE 1149+28      100    29 Dec - 02 Jan 1994     CV:AM    go0317 
     RE 1149+28       33    02 Jan - 03 Jan 1995     CV:AM    go0318 
     3c273            46    03 Jan - 06 Feb 1995     QSO      go0319

 * This Jupiter observation was conducted as a calibration/engineering


2.3 On-Line Access to EUVE

   Listed below are the various methods for on-line access to EUVE:

 o CEA World Wide Web (WWW)
   telnet 200 (for those without a WWW browser)

 o anonymous FTP
	Name:  anonymous
	Password:  type_your_full_e-mail_address

 o anonymous gopher

 o EUVE Electronic Newsletters
     Past issues -- available via the CEA WWW site
     Subscriptions -- mail ("subscribe
     Post message to all subscribers:  mail

 o GI Program
     Are you interested in finding out about or using EUVE data?  Do
     you need help in understanding EUVE data sets?  Do you need help
     in using the available EUVE data analysis software tools?  If you
     answer "yes" to any of the above, the Guest Investigator (GI)
     Program at CEA can help YOU!  For more information see the CEA
     WWW site or contact the Archive (

 o Public RAP
     The Public Right Angle Program (RAP) is a simple and easy method
     for researchers to propose for long-exposure EUVE imaging data.
     For more information on the Public RAP and the simple proposal
     process see the CEA WWW site or contact the EGO Center
     (  Mail all proposals to

 o Contact information for the EUVE Science Archive or EGO Center:

	Center for EUV Astrophysics
	2150 Kittredge St.
	Berkeley, CA  94720-5030
	510-642-3032 (voice)
	510-643-5660 (fax)

3. SelMon Test-Bed Experiment to Begin at GSFC
	by Tom Morgan, Applied Research Technology Manager

   The Center for EUV Astrophysics shipped the Selective Monitor
(SelMon) workstation and software to the EUVE Control Center at GSFC
on 8 May 1996.  The SelMon software application is being developed at
NASA's Jet Propulsion Laboratory (JPL) by Drs. Richard Doyle and
Dennis Decoste, both members of JPL's Artificial Intelligence group.

   SelMon will be part of an experiment funded by NASA Headquarters
and the GSFC Flight Testbed for Innovative Mission Operations
(FTB-IMO).  SelMon will be incorporated into the control center
architecture to receive real-time health and safety data from the EUVE

   Results from the SelMon experiment will indicate if satellite
health and safety monitoring and component trending can be performed
without traditional apriori construction of limits and thresholds.
SelMon is expected to monitor the health and safety of the satellite
more precisely than the traditional methods that use simple limit
checking.  The SelMon application utilizes a "learning engine" and
historical health and safety data to characterize nominal component
behavior signatures.  Significant deviations from nominal behavior
signatures will activate alarms and alert EUVE operators.

   The SelMon application created for EUVE is being studied by other
NASA missions. The Hubble Space Telescope ground systems reengineering
team, Vision 2000, was given a demonstration of the EUVE SelMon
workstation in late May.  The experiment will provide insight into the
potential for plug-and-play "black-box" learning systems to replace
traditional knowledge engineered rule bases.

  The EUVE Electronic Newsletter is issued by the Center for Extreme
  Ultraviolet Astrophysics, University of California, Berkeley, CA
  94720, USA.  The opinions expressed are those of the authors.  EUVE
  Principal Investigators and Newsletter Publishers: Dr. R.F. Malina
  and Professor S. Bowyer.  Newsletter Editor: B.A.  Stroozas.  Funded
  by NASA contract NAS5-29298.  Send newsletter correspondence to

  The EUVE project is managed by NASA's GSFC: Paul Pashby, GSFC
  Project Manager; Dr. Yoji Kondo, Project Scientist; Dr. Ronald
  Oliversen, Deputy Project Scientist; Mr. Kevin Hartnett, Mission
  Director.  NASA HQ: Dr. G. Riegler, Program Manager.  Information on
  the EUVE GO Program is available from Dr. Y. Kondo, Mail Code 684,
  GSFC, Greenbelt, MD 20771 at (301) 286-6247 or e-mail to

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