This is exactly what I needed to know, thanks! The plane with the camera had to follow a path that put the target aircraft directly in front of the Sun, that's all I need to know. My familiarity with schlieren was always with a laboratory setup including a special light source. Some pretty fancy flying!

I'll delete "camera" from the question; I can research that and consider asking elsewhere. Thanks!

@uhoh note that "The plane with the camera had to follow a path that put the target aircraft directly in front of the Sun" is still incorrect. If you read the Gizmodo article you posted "An airborne NASA B-200 King Air captured the images while flying above." and the Sun cannot be below the other aircraft (or we would not be here). Rather the light reflected from the ground was enough (and there you have more problems, as the reflection will be diffused and not parallel rays)

Oh, in that case I'm baffled. I think it will be a trip to the library this weekend then, and to another SE site with a new question after that. Thanks!

further reading: 1, 2 I think the quoted bit might not be correct and that they did use the Sun for the background. I'm not looking for the physics of the technique for this question, I'm trying to find out how these planes were oriented for this flight to backlight the shot. I still think the camera plane had to be below. I'll keep reading on this.

@uhoh "I'm looking for how these planes were oriented for this flight" that's not exactly clear from your question, and technically I have not answered it

That sentence of course takes into account what I've learned since posting the question an hour ago. Back then I thought there had to be an actual light source in yet another plane. I'll un-accept then.

@uhoh and NASA confirms that Gizmodo is right. see update.

yes all the popular articles may quote the same news release, but I think it's an error in the release and the plane with the camera was below the target planes, and the Sun was the background. Let's see how this one unfolds.

@uhoh does not make sense to me

the planes are obviously showing their cockpits in the photos, and they are performing a dangerous enough manoeuver

why fly inverted?

I'll take a look; are they oriented so that they have better visual contact with each other? If so, that could make the maneuver safer.

plus, usually imaging equipment is installed on the belly, not on the roof

they are at 30ft from eachother. if they did not have visual contact, they were flying blindfolded

to keep the sun out of their eyes then?

still, no amount of visual contact can make "safe" flying at supersonic speed 30ft apart and inverted

Oh NASA has all kinds of planes with all kinds of telescopes, and most of them point UP

no, there is only one, SOFIA

your stubbornness in not believing NASA (that describes a test they did themselves!) is baffling.

ok, but those don't point "up only"

I believe NASA quite a lot. Copy editors are human and can make mistakes. On this one I'm just not sure yet. It's only a few words in a news release, not a refereed publication.

I can accept that there is another aircraft that has telescopes and is capable of pointing them up

:-)

there is nothing in those photos that would make me think that the target planes were flying inverted above the camera though

you'll have to do a better job at convincing me, because the simplest explanation is the one contained in the press release

I'm not trying to convince you of anything, I'm explaining that I think it will turn out that the Sun is the background. It's what I think. That's it. I have no problem with being wrong because that will mean that I learned something and that there's a whole new kind of imaging that I don't understand.

Any time I can find something I don't understand, I win! :-)

But in this case I think it's the copy editor who has the same bias as you, and figured there must be something wrong with the copy, and then flipped the two planes, because "everyone knows that plane cameras look down"

But I know that high speed cameras with fast shutters and Lyman-alpha filters are working with incredibly low light levels, and so I think they need the Sun in the background to make it work.

It's the 2nd article that has more detail: 2

but like I say, if I'm wrong, then there's something really cool going on, and I learn sometihng new.

@uhoh and that you don't fly a supersonic formation inverted

-

sorry

If the flight were recent, would there be any chance that these aircraft would show up in FR24?

still, you are making an alternative hypothesis. if that hypothesis cannot explain all available data, or makes the explanation more complex, Occam's razor dictates that it is unlikely to be the real one

nasa flights on FR24? doubt, but you could try

It's just my gut instinct.

here's one aviation.stackexchange.com/a/40824/14213

but probably this news is much older than the time window that FR24 makes available to the general public.

plus, they took the images from a B200

I don't know any B200 with cameras pointing up

and finding the registration of those planes would be tough.

flightradar24.com/data/aircraft/n7na

and flightradar24.com/data/aircraft/n8na

the T38s are not on FR24

oh well. Gizmodo says the location is NASA’s Armstrong Flight Research Center in Edwards, California

I don't have a subscription so I can't go back more than 15 days.

en.wikipedia.org/wiki/… no upward camera

I see a lot of places to put a camera, just need a section of flat glass

NASA's budget is US$ 21 billion, I think they can change the glass without breaking it.

I'm done

(without breaking the budget, and okay without breaking the glass)

cheers!