TO:  All GCN Sites                                         24 Mar 05
RE:  Swift-PointDir Notices Added

INTRO:
This is the 5th announcement in the series about Swift in the GCN system;
ref:
     4th, 26feb05   http://gcn.gsfc.nasa.gov/gcn/admin/gcn_swift4.txt
     3nd, 14feb05   http://gcn.gsfc.nasa.gov/gcn/admin/gcn_swift3.txt
     2nd, 21dec04   http://gcn.gsfc.nasa.gov/gcn/admin/gcn_swift2.txt
     1st, 06nov04   http://gcn.gsfc.nasa.gov/gcn/admin/gcn_swift1.txt


SWIFT-POINTDIR NOTICE TYPE ADDED:
The pointing direction of the Swift s/c has been added to the set
of Notice types available.  It is called the SWIFT_POINTDIR Notice.
It contains the RA,Dec,Roll direction (J2000) that the s/c will next slew to
plus the time when the slew will start, the duration of the observation
on that location, and the Swift-generated name of the target at that location.
The boresights of all 3 Swift instruments are within ~2 arcmin 
of the direction contained in this Notice.  The Notice is issued 20-40 sec
before the slew begins.  Typically, the Swift s/c slews to a new location
3-6 times per 96-minute orbit.  Slews typically take 20-100 sec.


UTILITY OF THIS NOTICE TYPE:
This notice will allow automated instruments to "follow" the Swift
observation direction.  These instruments can then (a) have a shorter
slew time themselves should there be a Swift-BAT burst detection, and/or
(b) obtain pre-burst images of the burst region of the sky.   Please note
that the the FOV of typical ground-based instruments is much smaller
than the BAT FOV, so additional slewing by the ground instrument
to the actual location of the new burst will be required; and to get
pre-burst images, tiling of the BAT FOV will be required.


SIGN-UP and REQUESTS FOR CONFIG CHANGES:
People can take this opportunity to request that this notice type
be enabled.  (Your configuration is appended below.)  You can also
take this opportunity to request any other changes to your configuration
(either Swift-related or any of the other contributing missions as well).
Send those requests to:
  scott@milkyway.gsfc.nasa.gov
(Replies to this announcement's email_address go to another place and
will not be noticed for many days.)  And when requesting a change
to your configuration, please include your sitename.  Just put a marker
next to the items in your configuration (appended below) you want changed.


DISTRIBUTION METHODS:
While it is envisioned that this notice type will be primarily for
the automated-instrument sites using the socket connection method,
this notice type is also available in the email/pager/cell formats.
And this information is available at
  http://gcn.gsfc.nasa.gov/gcn/swift_pointing_tbl.txt


CONTENTS and FORMATS:
A detailed description of all the Swift Notices is contained in:
  http://gcn.gsfc.nasa.gov/gcn/swift.html
and for the socket sites, the packets are defined in:
  http://gcn.gsfc.nasa.gov/gcn/sock_pkt_def_doc.html
The Swift mission has packet types 60 through 84.
The email/pager/cell sites are encouraged to also read the sock_pkt_def_doc
web page, because the same fields that are in the socket packets
also appear as the various "TOKEN: value" lines in the email-based
distribution formats.
Socket sites are also encouraged to look at the socket_demo program
to understand the socket packet formats and the content -- there are
generic packet unpacking routines therein.
  http://gcn.gsfc.nasa.gov/gcn/socket_demo.c
Please note that both the sock_pkt_def_doc and the socket_demo.c
have been updated (since the last announcement) with modified descriptions
and content for this new SWIFT_POINTDIR notice type.


Sincerely,

Scott Barthelmy                      NASA-GSFC, Code 661, Greenbelt, MD   20771
PHONE:  301-286-3106                 (office)
PHONE:  301-346-3733                 (cell)
FAX:    301-286-1684                 (1st choice,  -1682 2nd choice)
EMAIL:  scott@lheamail.gsfc.nasa.gov
PAGER:  3013463733@mobile.att.net    (by email, 200 characters max per message)
WEB:    http://gcn.gsfc.nasa.gov/gcn


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