Question About Ballistics App and Kestrel

[JW74]

For the last year or so I have been using Ballistic AE and it has worked well so far. I now want to get a Kestel so that I can get more accurate trajectory tables. Do I need to get the Kestrel 5500 that has Density Altitude or can I get say the 3500 that gives Barometric Pressure only at my position and just put that into my Ballistic AE app? I also notice that with my new Applied Ballistics software on my computer that they don't even use Density Altitude.

Thanks for the help!

 

[JW74]

Thought I would post this link as it has the answer in a video from Frank at Sniper's Hide. Easiest thing to do is make reference altitude 0 and put in station pressure. That way you don't have to worry about calibrating your Kestrel for altitude, baro pressure ect.

Question About Ballistics App and Kestrel - SnipersHide.com Forums - Scout

 

[kyron]

Density altitude is pressure altitude adjusted for non standard temperature. So if it is asking for station pressure and temp it is asking for density altitude. Just in a way that is less confusing to people. gun)

 

[JW74]

Density altitude is pressure altitude adjusted for non standard temperature. So if it is asking for station pressure and temp it is asking for density altitude. Just in a way that is less confusing to people. gun)

Thanks Kyron, that's good to know. On my Ballistic AE today I put in station pressure, temp and humidity and then set the tab that says make pressure absolute. My Kestrel also gives density altitude, if I set the Ballistic for that then I only need to enter density altitude correct?

 

[kyron]

If you kestrel will give station pressure I would use that and set the pressure to absolute in your ballistic ae. The nonstandard temperature that is used to correct pressure altitude to density altitude is based on altitude. So it is comparing the current temp to the standard temp at your current altitude. It would quickly get confusing and very likely to make an incorrect entry to try to go from density altitude back to pressure altitude and temp.

The problem comes from the fact that even with an actual Mercury barometer the reading from that still does not give you the full picture of atmospheric density. You have to take temperature into account.

So a ballistic solver that is given station pressure and told it is absolute still needs temperature. Once it has that, it can calculate you density altitude which is what it uses to obtain your drop data. If you enter the density altitude where it is looking for pressure and then enter temperature it will correct the already corrected number for temperature. Resulting in it giving you bad drop information.

Density altitude is extremely important but most systems are not set up for you the user to even be aware that it exists. I would try to avoid using it for anything that is not specifically asking for it.

 

[kyron]

OK. I just reread your post. Yes if both your kestrel and your ballistic ae will run in density altitude mode, then that would be a good way to go as it should save you some data entry.