Icelandic of the day

From Bólu-Hjálmar's
Göngu-Hrólfs rímur
(46. stanza of 18. rhyme)

Geyst svo halur glæddi þar
gneistann sala Hárs borgar,
þrjár sem Baleygs blóðrauðar
bliki halastjörnurnar.

[There is a terrible mistake
in the ring-rhyme.]

The man did so quickly kindle
the spark of the halls of Hár's fortress
that it was as if there were three
blood-red tail-stars of Báleygr glittering.

1. Who is Hár?
2. What is his fortress?
3. What is the spark of his fortress?

4. Who is Baleygr?
5. What is a tail-star?
6. What is Baleygr's tail-star?

Regards,
Haukur