OzFclass

Recently had an experimental riflescope damaged by leaving the rifle with scope sitting in the sun.
Sun focused through eyepiece melted and damaged components inside close to Graticule.

Take care.

Peter Smith.

That is extremely unlucky Peter. How long did it take to cause that sort of damage?

Was the sun directly onto the lens, i.e. Rifle sitting on its butt or did you have it laying on a case?


Either way it is as you have pointed out, it is a lesson for all.

Craig.

Looking at the burn and melt marks in the scope, it would seem that the sun gradually tracked for at least 1/2 hour across the materials surrounding the Graticule.

My guess is that it happened after the rifle was hurriedly taken off the mound after a shoot while I scored the following shoots.

The eyepiece is an ideal lens to catch the Sun at an oblique angle and bring it to an intense focus.

I have seen damage to spotting scopes where the sun has inadvertently focused through the objective onto a prism or prism mounting and the heat has cracked the prism.

Anyway - it is good practice to at least cover the scope or put on lens covers. I usually just drape the shooting mat over the rifle and scope.

Peter Smith.

Sounds like it applies particularly to the eye-piece rather than the objective. And most scopes have long shades on the objective. I might retrieve my rear lens covers out of the boxes and actually use them .

A valuable lesson to us all.
I use lens covers but rarely put them on immediately after the shoot! to get back and score.

Eyepieces make great magnifying glasses - I use one from a cheap Tasco 10-40 to look at crowns etc.

We all remember how well magnifying glasses cook ants! The damage to Peters scope is indicative of same very hot temperatures and it is focused right onto the reticle!

As a matter of process, I take my lens covers off whilst on the shooting mound.

Then after firing the last shot, I reapply my lens covers prior to removing the rifle from the mound.

The logic behind this is:
1. It keeps dust off the lens
2. It keeps water or humidity off the lens
3. It provides physical protection if you were to drop the rifle / etc
4. It provides less chance of the covers falling out and getting lost.

As part of that same process, I keep a towel over the action to reduce the amount of dust/grit/rain getting into the action and trigger.

Reminds me of a convex mirror my wife left on the floor of our car many years ago.
The sun and mirror cast a very intense light beam onto the dash. The plastic dash had a deep burn for approx 300mm as the earth rotated. Lucky there was no fire

Cam

We smouldered a corn sack in the car boot when the sun focused through a one gallon glass demijohn.