<s>
HNSKY	B-Language
or	O
Hallo	B-Language
Northern	I-Language
Sky	I-Language
is	O
a	O
popular	O
free	B-License
and	I-License
open-source	I-License
planetarium	O
program	O
for	O
Linux	B-Application
,	O
macOS	B-Application
,	O
Microsoft	B-Application
Windows	I-Application
,	O
and	O
Raspberry	B-Operating_System
Pi	I-Operating_System
to	O
simulate	O
the	O
night	O
sky	O
.	O
</s>
<s>
HNSKY	B-Language
was	O
originally	O
created	O
by	O
Dutchman	O
Han	O
Kleijn	O
in	O
1998	O
,	O
who	O
continues	O
to	O
develop	O
and	O
maintain	O
the	O
application	O
.	O
</s>
<s>
Initially	O
a	O
basic	O
planetarium	O
program	O
,	O
it	O
has	O
expanded	O
in	O
functionality	O
to	O
include	O
the	O
ability	O
to	O
control	O
computerized	O
GoTo	B-Application
telescope	I-Application
mounts	I-Application
,	O
and	O
is	O
ASCOM	B-Application
and	O
INDI	O
compliant	O
and	O
supports	O
the	O
USNO	O
's	O
UCAC	O
catalogs	O
and	O
ESA	O
Gaia	O
data	O
.	O
</s>
