<s>
Nightshade	B-Application
is	O
a	O
simulation	O
and	O
visualization	O
software	O
for	O
teaching	O
and	O
exploring	O
astronomy	O
,	O
Earth	O
science	O
,	O
and	O
related	O
topics	O
.	O
</s>
<s>
It	O
operates	O
on	O
Linux	B-Application
,	O
macOS	B-Application
and	O
Windows	B-Application
.	O
</s>
<s>
Nightshade	B-Application
Legacy	O
was	O
open	B-Application
source	I-Application
and	O
is	O
no	O
longer	O
developed	O
.	O
</s>
<s>
A	O
completely	O
new	O
codebase	O
,	O
Nightshade	B-Application
NG	O
(	O
Next	O
Generation	O
)	O
is	O
licensed	O
under	O
the	O
"	O
Nightshade	B-Application
Public	O
License	O
"	O
,	O
a	O
non-free	O
license	O
with	O
field	O
of	O
use	O
restrictions	O
but	O
with	O
source	O
available	O
.	O
</s>
<s>
Nightshade	B-Application
Legacy	O
began	O
as	O
a	O
fork	O
of	O
Stellarium	B-Application
by	O
Digitalis	O
Education	O
Solutions	O
after	O
controversy	O
between	O
the	O
Stellarium	B-Application
project	O
and	O
its	O
commercial	O
contributor	O
about	O
a	O
focus	O
on	O
desktop	O
versus	O
planetarium	O
use	O
.	O
</s>
<s>
Development	O
of	O
Nightshade	B-Application
Legacy	O
ceased	O
around	O
2011	O
.	O
</s>
<s>
A	O
rewrite	O
,	O
Nightshade	B-Application
NG	O
,	O
was	O
begun	O
in	O
2011	O
,	O
with	O
a	O
change	O
to	O
a	O
non-free	O
license	O
with	O
field	O
of	O
use	O
restrictions	O
to	O
prevent	O
its	O
use	O
by	O
commercial	O
competitors	O
of	O
Digitalis	O
.	O
</s>
<s>
Several	O
Nightshade	B-Application
NG	O
"	O
preview	O
releases	O
"	O
have	O
been	O
made	O
.	O
</s>
