HEY CATSHOOTR So basically you could use your flip up cover with the hole drilled in it.So when the mirage is bad just snap it down and when conditions are good leave it up and with a piece of duct tape you could cover the hole when storing. SIMPLE Thanks for the info Tod
Spotting scope quality vs air temp
- Thread starter Alan Griffith
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[ QUOTE ]
GG... there is no formula for it.
Next time when you are out on a mirage prone day, take a black paper and some tape.
Cut a nickel sized hole in the middle of it and tape it to the front of the scope so you can lift it up to compare.
Look at a long range target that is in a boil.
Flip down the paper, and what you will see is a sharper target that is dancing.... nothing can make it stop moving, but the smaller opening will make it clearer.
What is actually happening is a long write, and will bore everyone to death... but a classic demonstration of mirage v aperture is the following - take the 80mm scope, and make a paper mask with four nickel sized holes at 12, 3, 6, and 9 o'clock, out by the edge, but still in the light path.
Take the scope out just after sunset and look west at a bright star - you will see 4 starts dancing independently around each other. That should throw some light on the subject. /ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/wink.gif
.
[/ QUOTE ]
I went out and tried this today for curiosity to see if there was a placebo effect or some real difference. one thing for sure FOV is much smaller.
UB
GG... there is no formula for it.
Next time when you are out on a mirage prone day, take a black paper and some tape.
Cut a nickel sized hole in the middle of it and tape it to the front of the scope so you can lift it up to compare.
Look at a long range target that is in a boil.
Flip down the paper, and what you will see is a sharper target that is dancing.... nothing can make it stop moving, but the smaller opening will make it clearer.
What is actually happening is a long write, and will bore everyone to death... but a classic demonstration of mirage v aperture is the following - take the 80mm scope, and make a paper mask with four nickel sized holes at 12, 3, 6, and 9 o'clock, out by the edge, but still in the light path.
Take the scope out just after sunset and look west at a bright star - you will see 4 starts dancing independently around each other. That should throw some light on the subject. /ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/wink.gif
.
[/ QUOTE ]
I went out and tried this today for curiosity to see if there was a placebo effect or some real difference. one thing for sure FOV is much smaller.
UB
goodgrouper
Well-Known Member
So what else did you find out? Was there a noticeable reduction in mirage? Inquiring minds want to know!
[ QUOTE ]
So what else did you find out? Was there a noticeable reduction in mirage? Inquiring minds want to know!
[/ QUOTE ]
No reduction in mirage but here is an example of decreased field of view, might need to go to a smaller hole for the mirage.
UB
So what else did you find out? Was there a noticeable reduction in mirage? Inquiring minds want to know!
[/ QUOTE ]
No reduction in mirage but here is an example of decreased field of view, might need to go to a smaller hole for the mirage.
UB
Jon A
Well-Known Member
Could you explain or show a pic of what you're doing? When I do it there is zero, zilch, zip, nada change in FOV. That's using holes as small as 1/2" diameter in front of a 75mm objective spotter as well as all my rifle scopes.
Jon A
Well-Known Member
[ QUOTE ]
Could you explain or show a pic of what you're doing? When I do it there is zero, zilch, zip, nada change in FOV. That's using holes as small as 1/2" diameter in front of a 75mm objective spotter as well as all my rifle scopes.
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Well, I may have figured it out. I was messing around with the spotter and video and found the FOV did get smaller in the camera. The reason was the camera can't get close enough to the ocular lens to quite get a full FOV in the first place, then when the lense is covered the FOV does get smaller. I found I could make the same thing happen to my eye by backing it up a little bit.
In short, the FOV can be decreased. But if it is, I believe it's because they eye isn't close enough to the ocular in the first place and covering the lens with the paper with the hole cut out makes it more dramatic. If close enough, it shouldn't affect the FOV.
Could you explain or show a pic of what you're doing? When I do it there is zero, zilch, zip, nada change in FOV. That's using holes as small as 1/2" diameter in front of a 75mm objective spotter as well as all my rifle scopes.
[/ QUOTE ]
Well, I may have figured it out. I was messing around with the spotter and video and found the FOV did get smaller in the camera. The reason was the camera can't get close enough to the ocular lens to quite get a full FOV in the first place, then when the lense is covered the FOV does get smaller. I found I could make the same thing happen to my eye by backing it up a little bit.
In short, the FOV can be decreased. But if it is, I believe it's because they eye isn't close enough to the ocular in the first place and covering the lens with the paper with the hole cut out makes it more dramatic. If close enough, it shouldn't affect the FOV.
