Mirage Shields

Thanks Pete...

I always thought that shooting inside a barn should be pretty much easy & trouble free conditions...The barn is somewhat large: 50 x 200 x about 25+ ft. high and the owner told me about even having some light wind conditions in there... Definitely true!, I put a couple of thin ribbons and to my surprise they had movement in usually 2 directions: Towards the targets lengthwise and to the right (south)...Nothing to really be concerned, but definitely were present.

After adjusting the scope for parallax (A Leupold Comp 40 X) there were no indications of parallax (moving head up & down) and I could see the dot and cross hairs very clear and sharp, but down the road and after maybe 1/2 the target those waves showed up and got worse the more we shot...

The lamps were above those targets, so for my second target I moved them a little higher thinking that maybe the little wind towards the targets could be somehow be bringing those heat waves (lamps) down...
No change, mirage (heat waves and ???) both ways but the horizontal waves were much more difficult to control and VERY critical...A slight movement off the EXACT center of the scope and you were in between the 8 & 9 rings.
I had eye surgery very recently because of an accident and while I don't have cataracts, after you mention it I am starting to consider that my eyes may be not fully healed or may be weak & sensible and getting tired more easily.

We will probably shoot on Saturday, I will try a battery fan (mounted on a tripod) and a lightweight scope tube, if necessary I will improvise a barrel shield...This time I will be checking with other shooters...

Maybe it is just that I have reached the age of: "I have never had these issues before" :D

Thank you all for the insights and advice...Have a healthy and happy year full of good scores...

Regards,

azuaro
 
Hello Members:

Today I shot at the barn once again and I just got back, I tried the fan as it was recommended by some members (pointed towards the barrel) and found that it works VERY WELL ! but my mayor finding was
that VERTICAL - HORIZONTAL mirage effect that I got a few weeks ago and the theme of this thread...

It is so true that we never stop learning and I am glad I did find what was going on because this thing was worrying me and making me feel very insecure as I attributed this uncontrollable effect to some eye surgery I had in both of my eyes.

This mirage I was seeing (V & H) is actually a mirage (barrel) superimposed over another mirage (lamp at target & warmer floor) that multiplies the effect into a Moiré...A Moiré in extremely difficult to control.

A Moiré is an effect widely known in photography and film making and in my case it was conformed of basically 2 or more sets of vertical waves (heat) at different angles given the distance in between barrel and target and some inherent wind currents inside the barn; when seen through the scope you see what appears to be an excessive and weird mirage effect but with a naked eye you hardly see anything; the waves at 50 yards definitely need the scope to be seen.

It is just amazing how this moiré effect moves around the reticle dot over the target...Today I was able to see the dot switching from the "X" to the 6 and 7 rings on the target without moving my eyes or head. Then by blowing the waves (fan) away from the barrel, what I was seeing though the scope diminished like 60 -70% and only a slight controllable mirage effect could be seen at the target...

So yes, the fan eliminated the mirage coming from the barrel and dealing with the remaining effect coming from the target area was not a very big issue.

I then tried what a member suggested and used a lighter in front of the barrel about 2 feet, this by itself was more than the mirage coming from the barrel and when added to the waves prevalent at the target , this made the dot dance even worse...
I then turned off the fan in order to aggravate the problem...This time I had 3 sets of horizontal/vertical waves at different angles and planes: barrel, lighter and lamps/floor; it was nothing but IMPOSSIBLE to keep the dot in that "X" even without moving the eye or head from the center of the scope; and any slight variation in the angle of any of the waves (linearity) by wind currents drastically moved the dot in all directions...It actually seemed like the dot was 3D and floating in front of the target moving by itself.

From here on I will be carrying that fan in my rest box and will look for cold illumination to be placed well above the targets.

Thank you all for your very valuable advice and for helping me resolve and learn a new issue.

azuaro
 
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Anyone has experienced this Moiré effect? and if so, how have you dealt with this problem or what do you suggest?

Thank you,

azuaro
 
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