26 March 2024

Thermal optics and their use; a researcher’s perspective and experience from Panama.

After two seasons using thermal and night vision optics to study nocturnal arboreal mammals we offer our perspective on these optics.

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Thermal optics and their use; a researcher’s perspective and experience from the neotropics.

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Trevor Hughes
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7 Comments

  • 26 March 2024
    Charles Foley

    This is fantastic information Chamtrev. Another benefit of having binocular vs monocular thermals is that the bi provides some degree of depth of field, which is not the case with monoculars. Do you have any advice for how to prevent ‘blowout’? At some temperatures once you look above a certain height with the thermal everything turns red (or white or whatever colour scheme you have), which makes looking for animals up trees really hard. Or at least it does on my fairly elder Pulsar, but perhaps this is not an issue with newer models. I’ve discovered that my Pulsar stops being effective at over 100 fahrenheit and below – 30 fahrenheit as the temperature differential between adjacent objects becomes too large. But again, it might be related to the age of my equipment.

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    • 26 March 2024
      Chamtrev74

      Hi Charles, you are correct binoculars provide a better depth of field and better spatial awareness than monoculars in our experience. It can be a decision maker on choice. We are actually surveying from platforms suspended at 10m to 20m so we are not quite looking straight up all the time rather slightly oblique. Upper canopy observations are tricky but we have found black hot mode on our optics resolves the blowout issues………mostly. Temperature has not been an issue with the conditions we have encountered.

    • 26 March 2024
      maurice-tijm

      Thank you for sharing. I already had high expectations of turning from thermal to infrared for id and observing, and not using the flashlight. Good to hear that you have such good results. Pity combined devices are still rare. What an impressive / dangerous tools. Thanks for the info on magnifications too, not that I can afford myself another thermal in the next 10 years..

    • 27 March 2024
      Lennartv

      @Charles, I experience the same thing with my Pulsar XQ23V, but didn’t when using a newer and more expensive Lahoux model. I think we just need a bit more high quality device. Sounds like a solid reason to get one :).

  • 27 March 2024
    Lennartv

    Very interesting piece! Personally I prefered the monoculairs for nightwalks because I would imagine it’s not really possible to keep an eye on where you walk anymore with binoculars. Also it leaves one eye adjusted to the night. I understand you only do stationary scanning with the thermals? Or have you also done night walks with the binoculars?

    Also interesting to see some footage of night vision camera’s. I had been thinking about that combination with the thermals. Interesting to hear that animals still have a clear response to the infra-red light though.

    Finally I am curious about your stats on Margay :). How often do you see them on average if we are talking about a number of ‘scanning nights’? And do you only see them from the platforms or also on foot?

    • 27 March 2024
      Trevor Hughes

      Lennartv. Personal choice is the most important and what works for you. We have trialled night walks in preparation for transects next season and found that you can travel slowly on foot using binoculars quite well as long as they have a low base magnification. Higher magnification tends to mean your spatial awareness and depth of perception is not too good.
      Infra-red, we have been using 850nm illuminators but 940nm may be the future for even less disturbance. Time and testing perhaps will answer this.
      You are not alone in your interest in Margay stats! We see them on average once every 4 survey nights. A survey night is 12-man (or woman) hours from an arboreal platform.

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