ranger finder dumb question

[axiluc]

im trying to understand why i need an angle calculator on a ranfinder if i am 20 feet up a tree and i range a deer i know that i am ranging in an angle but isnt the ligne beetween my range finder and the deer still straight lets say i range 30 yards going down im shooting in that same line that i am ranging wether it be horisontal or at an angle to me its still a straight line???? help!!

[paulaboutform]

im trying to understand why i need an angle calculator on a ranfinder if i am 20 feet up a tree and i range a deer i know that i am ranging in an angle but i. snt the ligne beetween my range finder and the deer still straight letsyou need say i range 30 yards going down im shooting in that same line that i am ranging wether it be horisontal or at an angle to me its still a straight line???? help!!

Actually, the distance from the you thatbase of the tree could be 18 yards but from your stand in the tree it may read 24 yards. The same applies to shooting extreme downhill angles. You would shoot the deer in the example for 18 yards. That's also why you should use a bubble level. If you cant your bow on those up or down hill shots you're going to shoot off left or right. It seems more noticeable on the steeper, longer shots. It's a lengthy explanation but i can assure you that's how it works. If you're shooting up or down, shoot your target for the distance it would be on the horizontal plane.

[JPjunkie]

The Arc rangefinders actually calculate the Run and rise to get there calculations Rise would be height off ground and Run would be distance to the deer I do this in some form or another just about everyday Cutting a set of stairs or cutting rafters Just about all your shots are Obtuse triangles

[racking up points]

Line of sight distance is further than horizontal distance that arrow travels. That's why a rangefinder would calculate the angle. It automatically compensates for this.

One way to think of this is to imagine you're on flat ground not in a treestand. 20y from the tree is your target. Now climb 20ft in the air and still the arrows only travels a horizontal distance of 20y. Because the line of sight is slightly more than 20y, (say 25y), there isn't a noticeable difference in POI.

But move the target away to 40y, and depending upon the elevation, line of sight could be as far as, say 48y. If your rangefinder doesn't compensate for the angle, it would read 48, you'd probably use your 50y crosshairs and miss high. (don't quote these numbers, they're approximations).

Gravity acting on the arrow is what causes this. In our heads we say, the target looks further away, but that's because we see line of sight and not the horizontal distance to the target. This is a reason most bowhunters miss high.

A trick I use is to imagine the deer is at my eye level in the stand. It helps me to better determine how far away he is from the base of the tree IF i can't range him.

This is more noticeable if you hunt from high perches, (say 20ft and up), or take long shots, (35y or more).

[Kegbelly]

Yes you are still shooting a straight line to the deer but at a slightly longer distance because you are elevated... Not to bore you with a bunch of math but it's a basic right triangle, where A squared + B squared = C squared.... so if the base of the tree is 30 yards from your target, that would be 90 feet, distance A. You are 20 feet up a tree, that would be distance B. The actual distance of your shot would be C, the longest leg of the triangle, about 92.2 feet or 30.7 yards. Gravity has some effect on the shot, but for all practical purposes, modern crossbows are so fast it sort of takes angles out of the equation. If you make a good shot in the kill zone it's a dead deer, 30 or 30.7 yards isnt going to make a significant difference. The thing to remember is to aim for the vitals. If you're shooting from an elevated position, your arrow will be traveling at a downward angle, so you need to compensate and aim a little higher on the deer to make sure you arrow passes thru the center of the vitals.

[racking up points]

Yes you are still shooting a straight line to the deer but at a slightly longer distance because you are elevated... Not to bore you with a bunch of math but it's a basic right triangle, where A squared + B squared = C squared.... so if the base of the tree is 30 yards from your target, that would be 90 feet, distance A. You are 20 feet up a tree, that would be distance B. The actual distance of your shot would be C, the longest leg of the triangle, about 92.2 feet or 30.7 yards. Gravity has some effect on the shot, but for all practical purposes, modern crossbows are so fast it sort of takes angles out of the equation. If you make a good shot in the kill zone it's a dead deer, 30 or 30.7 yards isnt going to make a significant difference. The thing to remember is to aim for the vitals. If you're shooting from an elevated position, your arrow will be traveling at a downward angle, so you need to compensate and aim a little higher on the deer to make sure you arrow passes thru the center of the vitals.

Pythagorean Theorem doesn't apply here. If A is the hoziontal leg, and B is the vertical leg of the triangle, then C, the hypotenuse, is line of sight. The arrow doesn't travel the distance of the hypotenuse, C, it travels the distance of the horizontal leg, A. You'd miss high at longer distances, Keg.

[Kegbelly]

Hmm, I know a quite a few deer that would argue that If that's the case then why are there angle compensating rangefinders if the shot distance is the same regardless if you are on the ground or 20 feet up a tree? Not trying to be argumentative, just looking to learn something, If I'm wrong I'll be the first to admit it. Is it just another marketing tool to make you think it's something else you need?
Edit.. ok i re-read your post, it makes sense. My mistake, 40 lashes with a wet noodle!

[racking up points]

[URL=http://s999.photobucket.com/user/derric ... t.jpg.html]

Take a look at the bow mode example. The hunter would miss high if he used line of sight instead of horizontal distance. For those numbers to be realistic, he'd have to be way up and the deer down some kind of ravine.

[racking up points]

Honestly had to look it up though, you made me second guess myself! But like you said, for most applications, this feature doesn't really make a huge difference. At long distances and steep up/downhill shots it comes into play.

[ComfyBear]

Phern, that's an interest theory, unfortunately it' s not quite the way it works. Gravity regardless of angle, affects all objects equally. Without going into a long-winded desertation, here's a simple explanation.

The horizontal velocity of an object is unaffected by the force of gravity for relatively short displacements. This means that the horizontal velocity is constant, while the vertical velocity is accelerating. The reason is because perpendicular vectors act independently of each other.

An object projected at an angle to gravity can be broken into its horizontal and vertical components. This horizontal velocity component is also unaffected by the force of gravity. Again, this is for short displacements.

The correct answer to "axiluc" question can be explain simply by "Pythagoras' Theorem", a2 + b2 = c2.

Let "a" = height of tree stand, "b" = distance from base of tree to target, and "c" = the distance from the top of the tree down to the target.

"B" (the hortizontal distance) is the true and actual distance which should be used to acertain proper POI.


Now let assume that a= 20ft, b=48ft, c= 52, as you can see when in the treestand the distance appears to be 52 feet to the target, when in fact the actual hortizontal distance is only 48 ft. The same applies if shooting up hill. In both cases, if one were to use "C" 52ft. as the distance to the target, the POI would be higher than it should be.

[Kegbelly]

OK, it appears I was wrong, wouldnt be the 1st time! Seriously though I've always ranged my shots from whatever elevation I was at and never had any problems shooting high, and a inch or so in POI isnt going to make much difference if you're in the vitals. But our stands arent that high either, about 14 feet is the tallest one I've taken a deer from, so that might have been a factor. To the OP, I hope this cleared things up for you

[Hunt it]

This is exactly why if you are going to hunt from tree stand you need to sight bow in from tree stand. over the years I've seen dozens of misses when people shoot over animal because bow sighted in on ground. Whole new game when 18-20 FT up.

[cb750]

So I was trying to figure this out myself this afternoon. I had been scouting for turkey's using a friends tree stand and was inundated with deer. I was trying to approximate their ranges so I would have a better idea where I would be shooting come the fall. That's when I thought a range finder would be handy. I searched them and stumbled on the ARC. Same as axiluc I couldn't comprehend the reasoning behind it. Thanks to you guys for explaining it, several ways, I am getting the picture. All the more reason to use a ground blind, I hate math . Thanks axiluc for asking the question. It has been bugging me all day.

[JPjunkie]

So I was trying to figure this out myself this afternoon. I had been scouting for turkey's using a friends tree stand and was inundated with deer. I was trying to approximate their ranges so I would have a better idea where I would be shooting come the fall. That's when I thought a range finder would be handy. I searched them and stumbled on the ARC. Same as axiluc I couldn't comprehend the reasoning behind it. Thanks to you guys for explaining it, several ways, I am getting the picture. All the more reason to use a ground blind, I hate math . Thanks axiluc for asking the question. It has been bugging me all day.

To technical for me shoot at middle of rib cage track it down and take it home

[axiluc]

wow thanks everybody very educationnal really got the little hamster running in my head i think i need to get an rangfinder that calculates the angles that answers my question thanks again..