Optical Oddities - Shooting from indoors to out in cold weather.

[ctshooter]

I try to take a little time every few days to shoot from my kitchen table out the slider door to a target at the end of the yard. The table is right next to the slider so only a few feet indoors and then outside. During spring and fall this setup works really nicely but I've noticed over this winter that I get some really weird optical shifting and mirage effects. It's really annoying to the eyes and fatigues them quickly as it makes the target 45-50 yards away look like it's vibrating through the scope. 

I can only assume it's happening at the slider where the warm and cold air are mixing. 

A lot of guys on here do the same type shooting from a window or slider - does this bother anyone? Have you figured out a way around it?

 

[Scouty]

I think Douger commented on this with his shooting shed recently. I'll see if I can find it.

 

[bambuino]

Try lowering your kitchen temp? Box fan to keep air moving faster, instead of eddying as mirage?

 

[Scouty]

Yeah it was Douger from Jan 16. Called it heat vision in the post & called it a halo in the posted video. About 1:50 in. I can't recall if he mentioned it again. 

Still can't access the post or thread through his profile but should be easy to find. Not sure if I ever watched the entire video but I don't remember a lot of detail about this effect. 

 

[MrP]

Try lowering your kitchen temp? Box fan to keep air moving faster, instead of eddying as mirage?

This is some good advice 

 

[ctshooter]

Damn - cold enough when I open the door. A box fan - yikes. Maybe I'll just wait another month or two.

 

[needledriver]

Perhaps using some card board, to create a window, and moving closer to the opening will help with the cold and vibrating target.

 

[bambuino]

Damn - cold enough when I open the door. A box fan - yikes. Maybe I'll just wait another month or two.

What I had in mind was a fan on LOW to enhance air mass mixing, perhaps laid on the threshold of the slider pointing up toward the header.

 

[ctshooter]

Damn - cold enough when I open the door. A box fan - yikes. Maybe I'll just wait another month or two.

What I had in mind was a fan on LOW to enhance air mass mixing, perhaps laid on the threshold of the slider pointing up toward the header.

ok - I can give that a try

 

[ctshooter]

To change the question a bit - do you think the transition from warm to cold air and the changing density could cause a shift in the projectile as well?

Sort of like light refraction when it goes from air to water.

 

[bambuino]

To change the question a bit - do you think the transition from warm to cold air and the changing density could cause a shift in the projectile as well?

Sort of like light refraction when it goes from air to water.

Prolly not like skipping a rock, but yes? Change in air pressure density...but you are prolly just within a yard or few of the slider...so...no worries?

 

[Airgun-hobbyist]

We have an indoor rifle range that has to exhaust the fumes with fans and so it creates a huge amount of mirage in the winter. If the fans aren't on it doesn't do it because it is not pulling the heat past the scope and into the unheated tunnel. A couple of things to try are turning your furnace off while you are shooting so it isn't forcing air movement, or even opening a door or window on the other side of the house. If the wind is favorable, it may pull a draft into the shooting window. You will be a bit colder but you will be able to see.

To change the question a bit - do you think the transition from warm to cold air and the changing density could cause a shift in the projectile as well?

Sort of like light refraction when it goes from air to water.

Interesting thought here. I'd think probably not. The pellet skirts or slug sidewalls generate plenty of friction heat leaving the barrel and are probably less effected by the change in temperature in the beginning of the flight. Now down range 100 yards or more, depending on the weather, humidity, density altitude, etc, probably will have more effect on flight in bitter cold than going from a warm barrel in the house does.

 

[ctshooter]

Thanks - I'm gonna try the crack another window open thing and see if it helps.

 

[L.Leon]

If you are going to let so much of the outside air in. Why not a hot water bottle inside your vest and shoot outside? You'll be warm enough for a shooting session. And won't chill up the kitchen or house.

 

[Impact701]

I turn on both bathroom fans and the range hood fans to reduce the warm air escaping out my window. This helps reduce the mirage. I usually only shoot 5 or 10 shots. 

 

[jimaok]

I made a framework and covered it with cardboard. I have a 15" square opening that I shoot thru and it keeps the inside the same temp so I dont get the mirage effect.