Best zoom lense for Nikon D-90 for capturing the milky way?

I have a Nikon D-90 and I use a Tamron AF 18-270mm F/3.5-6.3 Di II VC lense. I shoot a lot of action sports shots (hockey) but I want to shoot the milky way and I was considering getting a longer zoom lense however I don't know what to get.plus budget wise the ones I liked are out of reach. What do you recommend. It seems everything I read suggests an aperture of 2.8. Any advice would be greatly appreciated. My current lense is almost 5 years old and I've probably shot over 50, 000 pictures of more with it so not sure how long it's going to last. Mine is an older model and the filter size is 72mm.

You don't want a telephoto (longer) lens, you want a wide angle lens. Something like the 11-16mm Tokina f2.8 lens is ideal.

You need a wide aperture & a high ISO because you have to keep the exposure time down to about 25-30secs. Any longer & you start to get blur (star trails) from the motion of the earth.