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         ELECTRONIC NEWSLETTER OF THE EUVE OBSERVATORY 
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Vol 2, No. 13  12/9/92                                ISSN 1065-3597
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NEW VERY BRIGHT EUVE WHITE DWARF
________________________________
Dr Stephane Vennes reported that a new bright source in the EUVE long
wavelength ( lambda > 400 A) filters has been associated
with a catalogued white dwarf. This increases the total number of 
white dwarfs detected in the long wavelength filters to seven
( including the in orbit calibration targets and new sources
discovred during the first 30 days of the all sky survey).
This white dwarf is unexpectedly bright with an intensity
similar to Feige 24 in the Tin filter, fueling interesting
speculations concerning low density line of sights in the ISM.

NEW EUVE BACKGROUND LIMITS
__________________________
Dr Jerry Edelstein reports that new limits on the EUV background
in the band of the medium wavelength spectrometer on have been
obtained. These are at a level of .002 EM at T~ 10(6) K. These
limits are low enough to provide new constraints on ISM emission.

EUVE GO SUPPORT GROUP PREPARES FOR FIRST GO OBSERVATIONS
________________________________________________________
Dr Carol Christian reports that the Guest Observer Support Group 
is preparing for the first GO observations, beginning late in January. 
The NASA Peer Review met in October and NASA has sent the award letters
to successful proposers.  The EUVE Guest Observer Center is sending each
GO a questionnaire about his/her data acquisition and reduction requirements.
This will allow the EGO Center to plan for each GO visit and prepare the
data in suitable formats for the GO home institution's machines. At this
time, the EGO Center will also ask for more specific target information; 
emphemerides for planetary and lunar observations and exact coordinates
to correctly schedule the observations. The first GO's to visit CEA are
expected to arrive 8 to 10 weeks after the first GO data is taken. 

While the first year of observations has not begun, planning is already 
underway for the second year. The GO Handbook will be updated with the 
latest in-orbit calibration information.  The NASA Research Announcement
for the next cycle should be released in early April, 1993. Users with
comments on the first handbook are invited to send them in for incorporation.

Calibration of the spectrometer is continuing. Several different items are
being pursued including the detector background, a bright detector rim,
spectral resolution, and an occasional double rim. The results will be
part of an Ap. J. Letters article on the calibration of the spectrometer.
During the calibration, it was discovered that calculations of exposure
time were not sufficiently precise and the method for calculating was
changed. This method will also help with scheduling GO proposals to
obtain the requested exposure time. Finally, the medium wavelength
spectrometer throughput does not appear to match that expected from
the ground based calibartions, and this effect is being actively
investigated. Further information on status of GO Support activities can be
obtained by sending email to egoinfo@cea.berkeley.edu

EUVE ARCHIVE RELEASES LONG WAVELENGTH SPECTRUM OF FEIGE 24 
-----------------------------------------------------------
The DA white dwarf Feige 24 was recently observed by the EUVE for
wavelength and boresight calibration purposes.  Preliminary
extractions of the spectra obtained have now been completed, and,
following rapidly on the recent release of the Feige 24 spectrum from
the EUVE medium wavelength spectrometer, The Archive 
announces the release of the spectrum of Feige 24 from the long
wavelength spectrometer.  The bandpass of this spectrometer is
approximately 280-760 AAngstroms.  The exposure time of the
observation was about 45000 seconds.

ROUTINES FOR CALCULATING EUV ISM ABSORPTION DATA NOW AVAILABLE
--------------------------------------------------------------
Rumph, Bowyer and Vennes (1993, ApJ Submitted) have recently provided
a new estimate of the effective absorption cross-section of the
interstellar medium at extreme ultraviolet wavelengths.  This data is
now being made available through the Archive in the form of a C
program which calculates the ISM transmission for specified neutral
hydrogen column density, and neutral and ionized helium fractions.
The code utilizes the best theoretical and laboratory data currently
available for the hydrogen and helium bound-free absorption
cross-sections.  The ISM model includes absorption features due
to the autoionisation features of neutral helium near 206 A which have
been prominently detected in EUVE calibration spectra of white dwarfs.
The data are contained in the "ism" subdirectory in the archive:

ism/Makefile        
ism/README          
ism/ism.c           
ism/ismatten.c

The source files, "makefile", and  "README" help file may be
obtained from the ftp site or mailserver in the usual fashion.

If you have not used the EUVE public archive, you may obtain help by
sending e-mail to archive@cea.berkeley.edu with a message containing
the word "help" (omit quotes) on the first line of the main body of
the text (ie not in the subject field), with no preceding spaces. A
file containing information will be returned to you automatically.
	Jeremy Drake, EUVE Archive Scientist
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The EUVE Electronic Newsletter is issued by the  Center  for  Ex-
treme  Ultraviolet Astrophysics, University of California, Berke-
ley. The opinions expressed are those of the  authors.   Publish-
ers:  Roger F. Malina, C. Stuart Bowyer.Funded by NASA Contracts
NAS5-30180 and  NAS5-29298.
Send newsletter correspondence to: carlos@cea.berkeley.edu (Internet)
EUVE Public Archive via FTP: ftp.cea.berkeley.edu, pub/archive
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The EUVE Project is managed by NASA's GSFC.  The Project  Manager
at  GSFC  is  Mr.  Paul Pashby, the Project Scientist is Dr. Yoji
Kondo, the Deputy Project Scientist is Dr. Ronald Oliversen.  The
NASA  Headquarters  EUVE Program Scientist is Dr. Robert Stachnik
the Deputy Program Scientist is Dr.  Derek  Buzasi,  the  Program
Manager is  Dr. Guenter Riegler.  The Project Operations Director
is Mr. Kevin Hartnett.  Information  on  the EUVE  Guest Observer 
Program is available from:  Dr. Yoji Kondo,  Mail Code 684  GSFC, 
Greenbelt, MD 20771 (301)286-6247; euve@stars.SPAN.NASA.GOV