Coordination with IRIDIUM
The National Astronomy and Ionosphere Center and Motorola Inc., which
operates the
IRIDIUM satellite system, have signed a Coordination Agreement.
The Agreement addresses potential interference
produced by the communication satellite system with
observations of the astronomically important 1612 MHz line of the
OH molecule in the 1610.6 - 1613.8 MHz band. The Agreement guarantees
that :
-
(a) during scheduled observations in this band, between 10 pm and 6 am
Miami local time, IRIDIUM's out-of-band emission will be below -238 dB
W per meter sq. per Hz. level for all seven days of the week,
- (b) day time of up to 8-passes per year will be available for
observations defined as targets of opportunity that could not be
observed using a blanker provided by IRIDIUM. Such objects includes
comets, supernovae and other celestial objects that are of unknown
nature as yet.
Congratulations to Dr. Willem Baan, Dr. Mike Davis, Dr. Paul Goldsmith,
Dr. Thomas Gergely (of NSF) and Mr. Paul Feldman (Attorney), for
this successful outcome of their persistent efforts in this
negotiation process lasting over several years. The major achievement
for the astronomy community has been the inclusion of the level,
below which IRIDIUM has agreed to restrain their out-of-band emission.
However, in order to perform any observation in this band,
NAIC will have to install very expensive superconducting Notch-
filter, so that the effect of the up-link can be suppressed to
a tolerable level and to schedule most OH observations at nights.
The complete document can be viewed here: (
NAIC-IRIDIUM Coordination Agreement )
SMARG-Home
Reinaldo Velez (10/09/2000)