It completely depends on your budget. I have done some research, but have no hands on experience.
This was the cheapest I could find....
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followed by this one.....
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and this one......
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I have heard you can also mount a night vision monocular behind a red dot if you turn the brighness all the way down. That way you use the zero of the red dot and don't have to worry about sighting in the night vision.
Night vison is too far down my shopping list to be any more help.... sorry.
One last thought, the cheapes alternative are the green flashlights that allow you to see up to 100 years at night. I'm not sure if animals would see the light or not.
and this one......