The storyline and details forso far I can remember them:

- earth is invaded by an aggressive alien species
- a single earth battle cruisers ecapes and joins a good alien species to battle the evil species
- the one's who help earth can transform into a sort of super humanoids... bigger, shooting out of the lower part of their arms. They transform by holding a star against their forehead
- the leader of the good species is caught by the evil ones... in one scene you see him hanging at a cross, chained on the cross with a forcefield
- in the final battle, the lone earth battle cruisers is taking a beating... during the fight they split up in three parts and I think the biggest part is destroyed (the top part of the earth battle cruiser looks like a worldwar two battleship).

That is all I can remember. Does anyone know this movie ?
Thanks so much.

Was the star green?
Sounds like one the
Ultraman anime

Hey Straydog,
You are spot on ! It is ultraman!!
Thanks so much, I have been looking for this for ages.
I did some checking based on your tip and found the specific movie I was
Looking for.
It is called: the adventures of ultraman (1983)

Not sure if you can buy it on dvd but I did find it on YouTube.
"RedneckSpaceMan" uploaded the movie in 10 parts.

Thanks again !