I love the idea of more content that makes sense as a bridge from starter tech to space age tech. This should fit somewhere between a tank, and railguns.
My other mod adds a lighter 2x2 version. https://mods.factorio.com/mod/basic_cannon_turret

This is an edit of the Cannon Turret mods by VortiK, Ellswor, Kafoaai, Touhma, and Reckless and uses a mix of the assets and code from their mods.

8-way placeable like a railgun, so it is not able to be rotated after placement, but it's quickly minable

All configurable, but below are the defaults
cone of fire: 90°
range: 5-30
cooldown: 140 ticks
HP: 1000

Changes color by player
Can hit and damage asteroids

Works best with mods like Balance Ammo Damage by Stargateur and Disable Cannon Shell Friendly Fire by FiveYellowMice so that these aren't overpowered and don't destroy you and your base.

I made this mainly for my own multiplayer games, but in an attempt to make it work for anyone, most of the stats are configurable.
Original: https://forums.factorio.com/viewtopic.php?t=14957