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Corona Discharge at a Power Distribution Station in the Daylight.

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22 replies to this topic

#1 WiSi-Testpilot

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Posted 27 January 2020 - 23:23

Since I started playing with UV photography I have been looking for corona discharges. Looking through pictures from last summer, I found some. First I thought it were reflexes.
I will try it again.
Sony Alpha 6000, Pancake Lens SEL16F28, Baader U-Filter, Daylight (12:37, lunchtime), F/3.2, 1/60 S, ISO 320.
Best regards,
Wilhelm

Attached Images

  • Attached Image: UV_2_6_2019.jpg
  • Attached Image: UV_2_6_2019_Ausschnitt.jpg
  • Attached Image: UV_2_6_2019_Ausschnitt_1.jpg
  • Attached Image: UV_2_6_2019_Ausschnitt_2.jpg

Edited by WiSi-Testpilot, 27 January 2020 - 23:33.


#2 Cadmium

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Posted 27 January 2020 - 23:47

I think it is just sunlight being reflected off the glass glaze on the ceramic insulators.
There is also some kind of reflection off other things in the photo, not sure what those are made of or not.

#3 Stefano

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Posted 27 January 2020 - 23:55

Take a look here: https://www.google.c...d=1580169121535

I may be wrong, but from what I know corona discharges are only visible in very deep UV (SBUV, Solar Blind UV).

#4 OlDoinyo

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Posted 27 January 2020 - 23:58

I second this. One would not expect corona discharges off an insulator stack--that makes no sense. These are specular reflections; in the middle frame they are distorted by lens coma. Corona discharge is usually photographed below 280 nm, whereas you are lucky to get fown to 340 with the kind of lens/filter combination you used here.

#5 WiSi-Testpilot

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Posted 28 January 2020 - 00:39

Ok, sorry, probably you are right. But I will check it as soon as it is dry outside.
Best regards,
Wilhelm


#6 dabateman

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Posted 28 January 2020 - 07:16

Try again on a cloudy day. Or if you can at night. Then for sure it would be from the lines and not the sun.

I may have to see if I can see anything in low UV from my near by station. I just don't like the idea of standing outside for too long with a tripod. People around here are jumpy and might think I was up to something on the power lines.

#7 nfoto

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Posted 28 January 2020 - 07:32

These are reflections off the insulator with a healthy amount of lens coma added.

Repeat your photography at night time, preferably on a cloudy night with *no* rain . But probably won't show much as one probably needs resolving the deeper end of UV to show the discharges.

#8 WiSi-Testpilot

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Posted 30 January 2020 - 16:17

Thank you very much for your answers.
Today I cycled to our neighboring town of Stadtlohn to the Power Distribution Station. It is located at a former railway line, which is now used as a bicycle path.
The isolators are made of glass. As you already described in the articles above, there are reflections, not corona discharges.
Best regards,
Wilhelm

Vis
Nikon Coolpix S3200, F/3.5, 1/640 S, ISO 80
Attached Image: Stadtlohn_30_1_2020.jpg

F/5.5, 1/640 S, ISO 80
Attached Image: Stadtlohn1_30_1_2020.jpg

UV
Sony Alpha 6000, Lens SEL16F28, Baader U-Filter, F/4.5, 1/50 S, ISO 1600
Attached Image: Stadtlohn2_30_1_2020.jpg

F/2.8, 1/125 S, ISO 2000
Attached Image: Stadtlohn3_30_1_2020.jpg

#9 Andy Perrin

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Posted 30 January 2020 - 16:52

Still nifty to see one of these stations in UV-A!

#10 Stefano

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Posted 30 January 2020 - 17:24

I can be wrong, but isn't the corona blue-violet in air? So, if it emits visible light, can it emit long-wave UV light as easily?

#11 Andy Perrin

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Posted 30 January 2020 - 17:30

Stefano, I think it does emit some blue. In fact when I googled most of the spectra online look like this:
https://www.research...ns/figures?lo=1

Etc

Attached Images

  • Attached Image: 4C0BCA49-EC80-4E27-BBDC-37520FC560E2.png

Edited by Andy Perrin, 30 January 2020 - 17:31.


#12 Andy Perrin

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Posted 30 January 2020 - 17:33

I am not sure why people talk about imaging it in UVC based on those spectra. Possibly it is because they are interested in OH radicals rather than the nitrogen?

One thing I am sure about is that you can’t take UVA or visible pics of corona in the daytime because the sunshine will drown out the light from the corona. Possibly UVC imaging is an attempt to get around that issue.

Edited by Andy Perrin, 30 January 2020 - 17:35.


#13 OlDoinyo

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Posted 30 January 2020 - 21:25

It is because the OH A-X line falls in the solar-blind range, which enables it to be photographed in the daytime (during regular working hours) without interference from sunlight. Otherwise, it would be necessary to do such inspection work at night. The corona discharges are a sign of defects in or damage to the insulation.

#14 Stefano

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Posted 30 January 2020 - 22:24

If someone can, build a “corona machine”, with a voltage multiplier, a Van de Graaff generator, or something that can generate a very high voltage. Use special care with transformers if you decide to use them, since they can provide a dangerously-high current for a prolonged period of time. Make sure to generate a strong electric field (maybe 1 MV/m), but not high enough to make arcs. You should be able to hear a sizzling sound and see a blue-violet glow.

⚠️ BE CAREFUL WITH ELECTRICITY ⚠️

#15 dabateman

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Posted 31 January 2020 - 05:11

View PostStefano, on 30 January 2020 - 22:24, said:

If someone can, build a “corona machine”, with a voltage multiplier, a Van de Graaff generator, or something that can generate a very high voltage. Use special care with transformers if you decide to use them, since they can provide a dangerously-high current for a prolonged period of time. Make sure to generate a strong electric field (maybe 1 MV/m), but not high enough to make arcs. You should be able to hear a sizzling sound and see a blue-violet glow.

⚠️ BE CAREFUL WITH ELECTRICITY ⚠️

Or just buy an off the self plasma ball. I have a plasma plate. I thought I posted images somewhere. But may have to repeat it to see if it outputs UVC, now that I have the imager.

#16 colinbm

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Posted 31 January 2020 - 05:16

The plasma ball is inside a glass ball........what glass is it....?

#17 Stefano

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Posted 31 January 2020 - 11:30

Do plasma balls contain air or other gases? This can change the emission. Also, does the pressure change the emission, like in low and high pressure mercury or sodium lamps?

#18 Andy Perrin

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Posted 31 January 2020 - 15:39

I think they must be near atmospheric pressure because think how dangerous a pressurized glass ball would be to sell to children...

Update: Wikipedia confirms this; it’s atmospheric pressure noble gases in a glass ball. The glass probably absorbs all UVB and C.

Edited by Andy Perrin, 31 January 2020 - 15:53.


#19 NA_joey

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Posted 15 April 2021 - 15:11

View PostWiSi-Testpilot, on 27 January 2020 - 23:23, said:

Since I started playing with UV photography I have been looking for corona discharges. Looking through pictures from last summer, I found some. First I thought it were reflexes.
I will try it again.
Sony Alpha 6000, Pancake Lens SEL16F28, Baader U-Filter, Daylight (12:37, lunchtime), F/3.2, 1/60 S, ISO 320.
Best regards,
Wilhelm


https://www.nasa.gov...ts-off-on-drone

the spectrum is 240 - 310 nm most deception is done in.

you need a monochrome camera to record in UV-C a industrial camera monochrome camera or Astronomy Camera, Microscope camera monochrome.

Joey

#20 WiSi-Testpilot

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Posted 15 April 2021 - 18:51

Hello Joey,
https://www.ultravio...ra/page__st__20

the topic is still on my to do list. As soon as it gets warmer in the evenings, I'll try it again. Recently I was at the power line with my bike. Only the 110 V line is in operation at the moment.
Best regards,
Wilhelm

Edited by WiSi-Testpilot, 15 April 2021 - 18:52.