Originally Posted by leaddog
I am aware of all of this. My main concern is wether or not the unit works together and provides the correct info if all of the input is correct?
In that respect it is good. The Kestrel/ Horus model uses the same processor to run the weather and the ballistic calculations and they share memory. They are mostly integrated. The Kestrel calculates density altitude and temperature and transfers that directly to the Horus software. The Kestrel has a magnetic compass which measures magnetic north and calculates azimuths relative to true north any time a reading is taken.
When the software needs Direction of fire you point the kestrel's back to the target and take an azimuth reading which is stored. When you take a wind reading the velocity and azimuth are stored. When a trajectory is calculated it uses the difference of the angle between the direction of fire from true north minus the angle of the wind from true north to calculate the wind effects on the trajectory . It also uses true north and direction of fire for Coriolis correction calculation.
The important thing is that ALL azimuths entered (manually or automatically), stored, or displayed are relative to true north. The Kestrel instrument supplies the needed azimuths in that format though they can be entered manually. That seems to cause some confusion for new users of the Kestrel/Hours package. Many ballistic programs expect wind azimuth to be entered relative to the direction of fire. That is NOT the case with the Kestrel/Horus. It makes sense to use true north because the the software can have many azimuths to keep track of and true north does not vary if any other parameter is changed.
The only items that need to be entered manually for a given target are the target distance, usually taken with a laser rangefinder and the target inclination, estimated or measured. The wind velocity and azimuth for a given target can be updated without reentering the data for that target, even if you change targets.
All gun/cartridge/bullet info for up to 50 combinations can be stored as can 5 targets, each with their own ranges, inclinations, and wind readings. The main advantage of the combined Kestrel/Horus software is that it minimizes manual entry of data. As best I've been able to determine the calculations are done correctly using standard McCoy/BRL equations with spin drift and Coriolis corrections. The horus software uses only G1 BC, but but it can use piecewise BC adjustments as a function of target distance. It can also adjust muzzle velocity for ambient temperature of the ammo automatically, and it has a function that can correct trajectories bases on actual point of impact measurements.
The bluetooth/usb/serial interface in the Kestrel 4500 allows transferring weather data between a PC and and the weather mode even doing that unattended in a periodic mode. But In the horus ballistic calculation mode the interface can only be used to transfer gun/cartridge/bullet data between the Kestrel and a PC. The Kestrel-PC link cannot be used to execute the ballistic measurements and calculations remotely from a PC. That was the only disappointment I have in the 4500/Horus Maybe in a future version software version.
No single point wind meter located near the shooter can replace a shooter who is skilled at doping downrange wind. That's no different from using any commercial wind meter with any ballistic calculator. The Kestrel/Horus does not prevent a skilled shooter from using their own wind estimates.