Laser range finders and target illuminators are used in the military who can afford buying that expensive stuff.
To measure distance it is advisable for a hobbyist to use sound.
Light (and so does laser) travels at 300,000km per second. Sound travels at 330m per second. So light travels at a speed 909,090.9090 times faster than sound.
It is much easier to measure a sound signal and gate it accurately with commonly used ICs.
Measuring in the range of 300m air density and relative humidity can almost be negligated.
Use ultrasound transmitters and receivers and build your timing and evalution circuit on that basis.
Measuring the distance between the earth and the sun it would make sense using light. If the sun decides to turn off its light it will be dark on earth eight minutes later.
Boncuk