De or het ecliptica?

The correct Dutch article is:

de ecliptica

Rule Words ending in -ica: usually de. See the rule
Meaning (Dutch) (astronomie) de cirkel aan de hemel die de zon in één jaar schijnt te doorlopen, in werkelijkheid dus de aardbaan

How to use ecliptica

the eclipticade ecliptica
this eclipticadeze ecliptica
that eclipticadie ecliptica
our eclipticaonze ecliptica
your eclipticajouw ecliptica
every eclipticaelke ecliptica
which ecliptica?welke ecliptica?
a big ecliptica / the big eclipticaeen grote ecliptica, de grote ecliptica

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).