Best spot to aim for. Aiming farther left gives you a better angle towards the star.
Aim under the V-shaped top of the grey wall texture with the middle of the top crosshair approximately horizontal to where the lowest part of the sky can be seen through the wall. Other reference spots are available however, take a look at the above image and try to find some spot on the wall that you can remember to aim at.
This will also work
[[File:Jrb cannon 3.png|thumb]
