<s>
A	O
virtual	B-Application
observatory	I-Application
(	O
VO	O
)	O
is	O
a	O
collection	O
of	O
interoperating	O
data	O
archives	O
and	O
software	B-Application
tools	I-Application
which	O
utilize	O
the	O
internet	O
to	O
form	O
a	O
scientific	O
research	O
environment	O
in	O
which	O
astronomical	O
research	O
programs	O
can	O
be	O
conducted	O
.	O
</s>
<s>
In	O
much	O
the	O
same	O
way	O
as	O
a	O
real	O
observatory	O
consists	O
of	O
telescopes	O
,	O
each	O
with	O
a	O
collection	O
of	O
unique	O
astronomical	O
instruments	O
,	O
the	O
VO	O
consists	O
of	O
a	O
collection	O
of	O
data	B-Operating_System
centres	I-Operating_System
each	O
with	O
unique	O
collections	O
of	O
astronomical	O
data	O
,	O
software	O
systems	O
and	O
processing	O
capabilities	O
.	O
</s>
<s>
This	O
allows	O
scientists	O
to	O
discover	O
,	O
access	O
,	O
analyze	O
,	O
and	O
combine	O
nature	O
and	O
lab	O
data	O
from	O
heterogeneous	O
data	O
collections	O
in	O
a	O
user-friendly	B-General_Concept
manner	O
.	O
</s>
<s>
The	O
IVOA	O
(	O
International	O
Virtual	B-Application
Observatory	I-Application
Alliance	O
)	O
is	O
a	O
standards	O
body	O
created	O
by	O
the	O
VO	O
projects	O
to	O
develop	O
and	O
agree	O
the	O
vital	O
interoperability	O
standards	O
upon	O
which	O
the	O
VO	O
implementations	O
are	O
constructed	O
.	O
</s>
<s>
Euro-VO	B-Application
:	O
the	O
European	O
VO	O
(	O
a	O
partnership	O
of	O
VOs	O
including	O
AstroGrid	B-Operating_System
,	O
the	O
French-VO	O
,	O
ESO	O
,	O
ESA	O
...	O
)	O
</s>
<s>
The	O
eSTAR	O
Project	O
:	O
a	O
UK-funded	O
virtual	B-Application
observatory	I-Application
project	O
for	O
autonomous	O
ground-based	O
followup	O
to	O
transient	O
events	O
.	O
</s>
<s>
:	O
European	O
Union-funded	O
virtual	B-Application
observatory	I-Application
for	O
Earth	O
observation	O
data	O
.	O
</s>
<s>
Powered	O
by	O
the	O
CWI	O
MonetDB	B-Application
scientific	O
database	O
,	O
it	O
provides	O
access	O
to	O
TerraSAR-X	O
archive	O
of	O
the	O
DLR	O
.	O
</s>
