CelestronC90 Mak Spotting Scope, Black

if i used a 2x Barlow with the 39x eyepiece could i see shooting targets at 600-900 yds?

I want to use this for long range spotting 800-1500 yards.. Any ideas on how well this will perform?

I would like to use this as a terrestrial scope to view mountains in the distance. Would like detailed view of ski slopes. Aprox 20 miles away.

Could I mount this to an celestron AVX 8 inch scope? and use it with a star tracker?