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ROSAT Status Report #91

		ROSAT Status Report #91
		   April 22nd 1994

        Enhancements and new Features for ROSAT Archival Data Access
                  Mike Corcoran and Nick White, 
                         HEASARC, LHEA/GSFC.


This note describes new HEASARC services available for accessing the 
ROSAT and other HEASARC archival data. These are:

  1) FTP access at legacy.gsfc.nasa.gov to the entire ROSAT archive;

  2) Access via the World Wide Web;

  3) Enhancements to the HEASARC online service;

  4) Changes to the ROSPUBLIC database; and

  5) A ROSAT cd-rom update.

1. Anonymous FTP Access

ROSAT archival data is now being copied to a dedicated 
jukebox system that is permamently mounted to the HEASARC anonymous
ftp on legacy.gsfc.nasa.gov. The data can be found under the
directory rosat/data/INSTRUMENT/processed_data/XXXXXX/YYYYYYYY,
	INSTRUMENT 	= either hri or pspc
	XXXXXX		= sequence id group (from 100000 to 900000)
	YYYYYYYY	= sequence id

for example, data associated with the data set having sequence id
rp300023 is located in the directory


As of today about 84% of the data is available. We expect the remainder
to be copied from NDADS by the end of next week (4/29/94). As new
archival data is delivered it will immediately be added to the 
legacy ftp account. 

To minimize storage space, the data are stored on the jukebox in UNIX
compressed format.  Users can uncompress the data automatically when
ftp'ing.  To do this, simply "get" the file by specifying the filename
WITHOUT the .Z extension.  An example is shown below:
barnegat% ftp legacy.gsfc.nasa.gov
Connected to legacy.gsfc.nasa.gov.
220 legacy.gsfc.nasa.gov FTP server (Version wu-2.3(6) Thu Apr 14 16:40:47 EDT 1 994) ready.
Name (legacy.gsfc.nasa.gov:corcoran): anonymous
331 Guest login ok, send your complete e-mail address as password.
ftp> cd rosat/data/pspc/processed_data/300000/rp300023
ftp> ls rp300023.fits.Z
ftp> bin
ftp> get rp300023.fits
200 PORT command successful.
150 Opening BINARY mode data connection for /bin/compress.
226 Transfer complete.
local: rp300023.fits remote: rp300023.fits
4726080 bytes received in 93 seconds (50 Kbytes/s)
ftp> quit
barnegat% ls -l rp300023*
-rw-r--r--  1 corcoran  4726080 Apr 22 09:19 rp300023.fits

This automatic uncompression will work for both VMS and UNIX systems.
Users should note that automatic uncompression does NOT work with the
ftp "mget" command.
The current ndads service will continue to be maintained, as before. 

Due to popular demand, a new list of public ROSAT data is now
available via anonymous ftp from the legacy machine in the directory
rosat/doc/archive.  The new list includes all the currently available
public rosat data (for both US processed and MPE processed data sets)
for both the PSPC and HRI and should make identification of public data
much easier for users.  The list is issued in sequence-ordered and
position-ordered formats; these are named

	rosarchive_yymm.pos (position ordered)
	rosarchive_yymm.seq (ordered by sequence id)

where yymm is the year and month for which the archive list is
current.  This list replaces the lists
which are no longer used.

2. World Wide Web Access

The HEASARC has released a next generation BROWSE interface using the
World-Wide-Web, WWW. Through the xmosaic interface (obtained from
legacy.gsfc.nasa.gov in /software/www or from ftp.ncsa.uiuc.edu) it is now
possible to make coordinate and object name searches of all the various
catalogs and databases currently available through the HEASARC Browse
(including all the ROSAT tables and files). The data files can be both
displayed and retrieved via this interface. This new release includes an
interface to the SIMBAD name-coordinate resolver so that most astronomical
names will be recognized, plus a new HEASARC name-coordinate resolver.
Files can be downloaded or, by following the setup information, directly
display: fits images, postscript and ascii text files. We encourage users to
try this interface. The current capabilities are still quite limited
compared to the original browse, but the ease of use of this point and
click interface is a tremendous advance. The HEASARC plans to continue to
add additional capability to this method of accessing its archival data. We
are keen to receive feedback from users. To access the WWW HEASARC home
page please open 


The new browse iterface can be accessed from this page by clicking on
"browse". The rest is obvious....

3. New HEASARC online Service Features

While the WWW will be the future focus for the HEASARC remote access, the
current HEASARC remote login online service will continue to be supported
and maintained. This service has recently been moved from ndads to 
legacy. It is accessed in the same way as before i.e.

telnet legacy.gsfc.nasa.gov 

username: xray [note in lowercase]

legacy is an ultrix workstation and while all the basic services remain the
same, the switch from a vms to unix platform should make the service
more friendly to our unix users (who form the vast majority). There are
some new services in browse:

a) There is a new command called "simbad" which accesses a simbad name-
coordinate resolver. This allows you to enter any recognized astronomical
object name. If the object is in the simbad database, then the coordinates
are returned, and browse will automatically make a cone search around that
position (using the default radius used by the sc command). We thank
the SIMBAD group for making this available.

b) With the online service on legacy, the data in the anonymous ftp can
now be directly accessed from browse. Thus all the rosat public archive
data can now be extracted (using the browse xp command).

c) For large lists of coordinates it can be a bit tedious to type in all 
the coordinates. It is now possible to make searches by e-mail. A list
of source positions and coordinates canbe submitted and the results will
be e-mailed back. This is particularly useful if e.g. you have a list of
objects and want to check if rosat observed them and if they are
in the archive. To use this service, send an empty e-mail message
to hdbreq@legacy.gsfc.nasa.gov. Instructions will be automatically 
sent back by e-mail.

4. Changes to the ROSPUBLIC Database
The ROSPUBLIC database is presently being modified to make clearer
which data are actually in the public archive.  The new data table will
contain only those data sets which are currently in the public domain,
and the public date information given in the table will indicate the
date the data actually entered the public domain.  The previous usage
of the public date in the ROSPUBLIC data table was incorrect in many
cases and caused some confusion on the part of users.

5. ROSAT CD-Roms

All of the broad-band images from the mission will be distributed on cd rom. 
Volume 1, consisting of the first six months of data released to 
the archive, is now available. It was first distributed at the Washington 
AAS meeting in January. The cd rom can be browsed from xmosaic by opening:


The second volume will contain all the remaining archival images released 
up to December 1993. It is currently in production and if all goes well 
will be distributed at the June 1994 Minneapolis AAS meeting. If you would 
like to order a copy of either volume please send an email to 
ksmale@lheavx.gsfc.nasa.gov. Please include your name, address and which 
volumes you would like. Supplies are limited and will be sent on a first 
come first serve basis.