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Дата изменения: Wed Feb 22 23:35:12 2012 Дата индексирования: Tue Oct 2 02:45:34 2012 Кодировка: Поисковые слова: внешние планеты |
Arecibo presently supports VLBI for up to a
maximum of 4% of its astronomy observing time. A hydrogen maser
frequency standard is available for VLBI, this being
a unit from Symmetricon Inc.,
(Model No. MHM2010.) For information on this unit
see
http://www.symmetricom.com/products/frequency-references/active-hydrogen-maser/MHM-2010/.
The maser also serves as the Observatory master clock.
Arecibo is equipped with a a VLBA4 recording system, compatible
with the HSA, EVN and Global networks, and the 305-m telescope is
available for scheduling with any of them. Any
proposer wishing to include the 305-m telecope in their VLBI
observations should submit a proposal to the HSA, EVN or
Global networks as usual, rather than to Arecibo. All proposals should contain
special justification for inclusion of Arecibo.
(Observations with ``ad-hoc'' arrays will also be considered. In this
case, proposals should be submitted to Arecibo as specified at http://www.naic.edu/~astro/proposals/proposal.shtml.
It is the
proposers' responsibility to ensure that telescope time be granted by
all observing facilities involved.)
From 2004, Arecibo has used a VLBA4 Data-Acquisition Rack, together with a Mark-5A disk-based VLBI recording system. This allows up to a 1 GBit/s data recording rate. The Mark-5A system also allows Arecibo to participate in real-time e-VLBI with EVN. Migration to an RDBE VLBI digital backend, and Mk5C recorders is anticipated for 2012, with test firnges with the HSA having been successfully obtained in June 2011. This will permit data recording rates of 2- or 4-GBit/s.