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LUX Measurements at the 2023 Annular versus the 2019 Total Eclipse

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#1 foxwoodastronomy

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Posted 21 October 2023 - 06:54 AM

I measured LUX at my 2023 annular observing site with the same sensor and setup that I used to measure LUX at the 2019 total solar eclipse. I point an ambient light meter at the observing area (not at the Sun). The goal is to measure what people are experiencing regarding the light. At C1, the observing area LUX was similar in 2019 and 2023. The lowest LUX recorded at the annular was 865.98. A tremendous drop in illuminance, but since it occurs over 86 minutes, our eyes can dark adapt, and we perceive very little change in the difference in ambient lighting. At the annular eclipse, I perceived a difference in the "character" of the light, but I can't say that I thought it was darker. During totality in 2019, the LUX dropped to 1.97, with a total duration of 2m 30s and an umbra width of 88 miles. The 2024 total eclipse should be slightly darker. For more information visit my website. (LUX chart credit Wikipedia)

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  • 2023 and 2019 LUX and LUX chart together 2600px for CN.jpg

Edited by foxwoodastronomy, 21 October 2023 - 06:55 AM.

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#2 BellX2

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Posted 21 October 2023 - 09:36 AM

What instrumentation did you use to measure this? Are there data logging light meters or did you record it manually? This is a very interesting way to observe the Eclipse.


Edited by BellX2, 21 October 2023 - 09:37 AM.


#3 foxwoodastronomy

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Posted 21 October 2023 - 10:17 AM

What instrumentation did you use to measure this? Are there data logging light meters or did you record it manually? This is a very interesting way to observe the Eclipse.

Pasco, Bluetooth Wireless Light data logger.  I used this device both times.  It's a great little data logger.  It gets programmed wirelessly (Bluetooth) via an iPad with the free Pasco software SparkVue.  It has an ambient light port and a direct color port.  I did some unique eclipse color data in 2019 and I have some color data from the 2023 annular that is interesting also.  I am going through that data right now.  https://www.pasco.co...ts/item/ps-3213



#4 MEE

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Posted 21 October 2023 - 04:11 PM

What is your source for the lux measurement chart?(showing what the illuminances correspond to)

I’m trying to see what they are defining as overcast (1000 lux) - “overcast” can mean many things

#5 foxwoodastronomy

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Posted 22 October 2023 - 07:08 AM

What is your source for the lux measurement chart?(showing what the illuminances correspond to)

I’m trying to see what they are defining as overcast (1000 lux) - “overcast” can mean many things

Hi MEE, there are many ways to measure light, but this Wikipedia article on LUX had the chart that I thought represented what I am trying to show.  Of course, all descriptive examples have a range of LUX values, but what is in this chart is close to other examples that I have seen published.  https://en.wikipedia.org/wiki/Lux

Thanks for your question.





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