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caught a Sprite! 16/17 August

I had SpriteWatch shift last night (scheduled for this entire week in fact) and observed storms over Spain that happened in two locations. Clouds were actually close to the camera at Pic du Midi but miraculously there were enough clear skies near the site. It is always difficult when there are two candidate storms. At a certain point the storm in the south became less active and I decided to point over it again (a relatively steep tilt because of the not too far distance to the storm). 5 minutes after doing this, a glorious image popped out at me at the control website! Anxiously I was trying to aim a possible next one even in the center of view, but soon I saw clouds cover up the cameras view :(

You can see it at www.eurosprite.net

I went to bed with my webcam in event capture mode with the Japanese program "UFOCapture". As I checked again at daybreak, it appears a storm has come out of the Pyrenees and its distant lightning flashes were recorded in the dawn light! Just too bad I did not wake up a little earlier to see it for myself :roll:

I've got some interesting material though, have to bring some stuff online, also video of the 10th of August storm for which I held a portable electric field mill in front of the camera as lightning flashed, very interesting to see it change.

cheers!
Oscar

PS. some other sprites were captured las week as well (carrot-type)!
 
Cool. Maybe you should provide us all with some Sprite photography tips.

Maybe we should unleash Mike Hollingshead on this stuff as well as he shoots storm scapes and auroras well. Perhaps a Mike H with sprite would be way cool.
 
Sprite Photography tips

Cool. Maybe you should provide us all with some Sprite photography tips.

Maybe we should unleash Mike Hollingshead on this stuff as well as he shoots storm scapes and auroras well. Perhaps a Mike H with sprite would be way cool.


Well, anyone with their own photo of a sprite would be way cool :D
But it is hard to do, it seems, one needs a lot of patience. The research way of doing it is by purchasing a B/W low-light security videocamera system (usually below 0.02 lux sensitivity), e.g. with Sony ExView HAD sensors of 1/3 or 1/2 inch. Color cameras are less sensitive because of the color filters in front of each specific pixel, and the number of pixels available for each color is reduced compared to B/W, appearing more noisy.
If you look hard enough there are probably solutions which are not too expensive, such as SuperCircuits, which would be below $100. Japanese use the very clean Watec cameras ($500 range), and in Europe some amateurs in the meteor patrol business have succeeded in recording sprites with e.g. a Mintron. For EuroSprite 2005 we use JAI cameras.
These cameras have C/CS mount, and there are a number of lenses out there with f/0.8 or f/0.95, brighter than normal photographic lenses. With this setup recording stars of magnitude 6.5 is no problem at all - my webcam the Philips ToUcam Pro II does very well in low light, but can resolve only 2nd magnitude stars with reasonable difficulty, for comparison. It is said that the average sprite is as bright as a moderately bright auroral arc.... and I have asked Dave Sentman (Univeristy of Alaska) to which magnitude a sprite compares... he said this would be about magnitude 3 stars. These video observing systems do not connect via USB, but some do FireWire, and serial connection/TV capture cards. They have their own 12V power supply (adapter).

Perhaps photographic methods could work as well. The problem is, a sprite lasts very short (less than 1/100 sec) and is the brightness of this moderately bright aurora. The effective ISO you need is incredible - if you use ISO3200 film or digital, even then use a lens of f/1.4 or lower (there are some 80mm f/1.2, and Canon even makes a 50mm f/1.0 L)
I have to look it up, but sprites emit red light in the 650 nm area... the IR block filter of a digital camera hopefully does not start blocking too much in this range.

Well I would say, anyone who has a digital SLR or low-light video system could try it, once you know you have clear skies and a distant MCS on the horizon. Do so constantly, and you might get rewarded. Sprites happen over the stratiform regions of mature to dissipating systems. Don't point too low over the storm if the storm is close - the sprites happen between 40 and 90 km above the storm. If you have an active storm nearby, hunt for blue jets or other phenomena. These are unique! Very few observations to date. In the tropics, hunt for Giant blue jets.

Usually people observe from mountains (or space) This is because the path between the sprite and the camera contains air, and you want to minimize haze and absorption (especially blue light does not travel long distances). That said, people have been successful in recording from near sea level.

I wish anyone who is attempting to catch them good luck, and contact me if you do it, I am very curious which methods prove to work besides low-light video.

Oscar
 
Re: Sprite Photography tips

But it is hard to do, it seems, one needs a lot of patience.

Does seem difficult. I didn't realize they were so faint, but I guess that makes sense otherwise we would notice them all the time. So a time exposure is probably out unlike for lightning. Well, I guess you could in really black conditions as long as you had really good equipment that was very fast (ISO and Lens). This is probably beyond a lot of folks. Does anyone have any pictures take in this way you describe with the ISO 3200 and fast lens?
 
Oscar, at what elevations do you normally make the observations from, and what distances from the storm are typical? I may try this sometime as where I live (West Virginia mountains) might meet these observation criteria. I have less than a 2 to 3 hour drive to a few 4,000 ft+ ridges, and am less than an hour from quite a few 3,000 ft+ mountaintops. All in remote locations with little or no light pollution.

Many nights in July and August there will be MCS activity approaching from Ohio with crystal-clear skies in the mountains. They typically cross the state line into WV after sunset, and due to the loss of heating and outrunning of the typical front to the north, they are usually long dissipated by then - almost like clockwork :( Maybe instead of heading west into Ohio to get lightning photos, I should head east into the mountains to try this. Sounds interesting, I'm always looking for new storm phenomena to chase.
 
Hi Dan,

I think the difference between 4000 or 3000 ft mountains does not matter much, unless there would be an inversion between them at the top of the boundary layer. I think one would still be much inside the boundary layer anyway, which could easily be at 6000 ft in summer. The most important are local haze conditions and having no light pollution, also the moon could be annoying (I am currently at Pic du Midi, 2880m and the Milky Way was so bright - until the moon came up!)
Try testing you video camera on a nice constellation, then look up all the stars you can/can not see in the images, to have an idea of the sensitivity of your system.

But yes, go there and do it!
Oscar
 
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