Trip to the "Desert" - OR - Oh That Insane Mirage

Rocketmandb

Old Salt
Full Member
Minuteman
  • Nov 2, 2018
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    A friend and I took an epic trip to the desert this weekend. We left Friday late afternoon, stayed in a cabin near Truckee that night, then got up early and headed out to the "desert." Why the quotes around desert? See below

    Waking up in the morning in Truckee - remember, we're 4 days til May here...
    night in Truckee.jpg

    You can't tell from the pic, but it was still snowing.

    We drove out to the desert and found this amazing dry lake bed out in the middle of nowhere. What a great place to shoot, right?
    lakebed3.jpg


    looking back from lakebed.jpg


    We set a 24" circular target at 1860, but...

    Rain is coming.
    1745775336552.png


    The rain clears and we get the 300 PRC and spotting scope set up.

    What's wrong with this picture?
    mirage target.jpg

    The arrow is pointing at the target. Does that look like a 24" circle to you?

    Here's the view through the spotting scope which is a little higher off the ground.
    mirage spotting 3 copy.jpg

    You can clearly see the mirror image with two "targets" shown. You can also see the kaleidoscope pattern through the spotting scope below (not the target area, but close by).

    mirage spotting 2 copy.jpg

    I'd never shot across a dry lake bed before, so this was a learning experience for me. What was amazing was how much mirage there was AND the mirror imaging taking place. The pictures look kind of bright, but in reality, at this point just after the rain, it was still cloudy. Mirage was just nasty. I tried a few shots at 1860, but we couldn't even see the misses. My assumption is that the atmospherics causing the mirror imaging also affected viewing the actual target location, so the POA and POI were significantly different.

    We ended up moving the target to a closer (and higher) area to get it higher above the lake bed. Impacts were still about .3 mil under what I would have expected.

    There will be a video forthcoming - regardless, it was a fun day.
     
    As it happens, we just did the XLR class last week where I explain this exact problem and show some video. This is why I don't advise clients to bring scopes over 25-27X or so, we often need to shoot closer to 20x anyway. Understand, you don't actually see the target, you see an IMAGE of the target created by light rays reflected off of it. Those rays are subject to various issues as they travel through the atmosphere, and the actual position of the target itself may be quite displaced from the observed image. Everyone has seen the bent spoon in a glass of water, air does the same thing.