James Webb Telescope.

[MingtheMerciless]

Some fantastic engineering going on here, well worth losing yourself for an hour or so watching things like Beryllium mirror manufacture and polishing to its 5 layer sunshield unfurling and tensioning. The shield is 5 layers, each the size of a tennis court and as thick as a human hair, currently its +60C on the sunward side of the shield and -194C on the instrument radiator on the cold side!

https://www.nasa.gov/mission_pages/webb/main/index.html

[Mr. Dazzle]

Live tracker is here....

https://www.jwst.nasa.gov/content/webbL ... sWebb.html

I watched the launch live on Christmas Day. I tell you what, Arriannespace have some shit PR, 99% of it was just a computer generated graphic seemingly from about 2008.

Fair play to them though, they did such an accurate job on the launch that the telescope is gonna use much less fuel than anticipated to get it its final orbit, that's gonna give about 5 years more running time on station.

[Taff]

[MingtheMerciless]

Lol,

The Russians don't find that funny as the sent probe to Venus and it survived the hellish descent and environment only for the lens cover to melt onto the lens.

my favourite is below, its one of the mounting points on the 747 that used to carry the Shuttle's around.

Screenshot 2022-01-04 at 19.33.08.png (756.82 KiB) Viewed 492 times

[Mr. Dazzle]

It's all fully deployed now...so in theory the really scarey bit is over! It had something like 350 individual releases, folds, springy bits etc. which had to happen and most of then were 'single point of failure' type things. Normally it'd be insane to have that level of dependence on single things working, but this is hardly a normal device.

https://www.jwst.nasa.gov/content/webbL ... sWebb.html

I've been reading some more stuff on how various bits of this thing work. Because the telescope is built from scratch (Hubble is actually a rejigged spy satellite design) there's loads of public info on the tech inside it. Of particular interest to me was the technology they've invented to allow the 18 mirror segments to be aligned in space. The same light measuring equipment is now in the eye scanners the hospital use to measure my corneas

[JackyJoll]

When they look right back to far away, long ago etc., what if they alter the outcome of the formation of the universe by observing it?

You know, like they say about that quantum shit!

[Skub]

If they point it in the opposite direction will it see into the future?

[Mr. Dazzle]

If they point it in the opposite direction will it see into the future?

[Yambo]

I'm sure there'll be some fantastic things to come from the JWT but unfortunately, for Joe Public they won't have the same impact as a lot of the Hubble images have had over the years.

Without the equipment to take images in the visible spectrum it's very much a specialist bit of kit. Hopefully Hubble can continue functioning for a few more years.

[Mr. Dazzle]

I dunno about that...the vast majority of the images you see are false coloured ones processed within an inch of their lives to make them look nice. They're not what you'd see if somehow Hubble had a giant eyepiece. In fact AFAIK Hubble can't even take colour photos, very few scientific instruments can.

This one for example is "just" different colours for different elements, it doesn't actually look like that. Its a composite of lots of photos.

[MingtheMerciless]

If they point it in the opposite direction will it see into the future?

Lol, it can’t do that as it can only look away from the sun. The optics/sensors have to stay around -250C to stop their our heat/IR emissions swamping what it’s looking at.

It also only has thrusters on the sunward to stop any contamination of the mirror so the telescope has to sit just the right side of the LaGrange point. Too much correction and it drifts past the point of no return to sail off into space.

[Yambo]

I dunno about that...the vast majority of the images you see are false coloured ones processed within an inch of their lives to make them look nice. They're not what you'd see if somehow Hubble had a giant eyepiece. In fact AFAIK Hubble can't even take colour photos, very few scientific instruments can.

This one for example is "just" different colours for different elements, it doesn't actually look like that. Its a composite of lots of photos.

Most astrophotographs are made up of lots of separate photos. To get really good images you might have to take 10 hours of maybe 5 minute exposures, stack the lot of them together to make one image then process that image to bring out the colours and highlights that you want. You can do a lot of processing on photoshop but there are other programs available that are more dedicated to astrophotography. I use Pixinsight.

A lot of imaging is done with filters, to filter out wavelengths of light you don't want and the better images of nebulae for example are done with a monochrome camera and red, green and blue filters. You can also get specific wavelength filters for Ha (hydrogen alpha) for example but filters are expensive and monochrome cameras are more expensive than one shot colour (OSC) cameras.

Anyone can produce images in the Hubble palette, you just assign different colours to different channels when processing. But images are subjective and some people prefer what comes with what equipment and software they've got. Some people simply don't like the Hubble palette

Processing is the main part of astrophotography as a lot of what you might be imaging can't be seen in one image. Where Hubble scored is the lack of atmosphere to look through and low noise - electronic noise is one of the reasons you need so many images and why you need perhaps 100 calibration frames.

Do you want to make a small fortune?

[Skub]

If they point it in the opposite direction will it see into the future?

Lol, it can’t do that as it can only look away from the sun. The optics/sensors have to stay around -250C to stop their our heat/IR emissions swamping what it’s looking at.

It also only has thrusters on the sunward to stop any contamination of the mirror so the telescope has to sit just the right side of the LaGrange point. Too much correction and it drifts past the point of no return to sail off into space.

[David]

If they point it in the opposite direction will it see into the future?

Lol, it can’t do that as it can only look away from the sun. The optics/sensors have to stay around -250C to stop their our heat/IR emissions swamping what it’s looking at.

It also only has thrusters on the sunward to stop any contamination of the mirror so the telescope has to sit just the right side of the LaGrange point. Too much correction and it drifts past the point of no return to sail off into space.

They say that, but......

[David]

The latest images are in...

The Great A'tuin is looking good....

[Mr. Dazzle]

Stuff

Yeah, exactly. So while Hubble looks in visible light and JWST is primarily looking in IR you'll still get Hubble-like pictures released from JWST.

There's nowhere you can go in the universe and actually see that pillars of creation view, its a "fake" made up by bringing together lots of narrow/specific views and combining them into something we can wrap our eyes around. They'll do the same thing with JWST I'm sure.

[KungFooBob]

You don't need colours. Aliens are all either Grey or Green, it's a 50/50 chance.

[Yambo]

Stuff

Yeah, exactly. So while Hubble looks in visible light and JWST is primarily looking in IR you'll still get Hubble-like pictures released from JWST.

There's nowhere you can go in the universe and actually see that pillars of creation view, its a "fake" made up by bringing together lots of narrow/specific views and combining them into something we can wrap our eyes around. They'll do the same thing with JWST I'm sure.

The Hubble photo of the 'pillars of creation' is not a "fake", that's nonsense. There are amateurs taking images of the pillars of creation. It's a small part of the Eagle nebula and while they cannot get the resolution that Hubble gets it's not difficult to get an image of the nebula and see the very same structure. The bigger the aperture of the telescope the better and a few hours of captured data and the pillars of creation will be on your computer screen albeit probably part of a wider field of view.

The procedure is not difficult but the photographer needs a motorised telescope mount to keep on target, precisely aligned with the polar axis. Focus needs to be spot on and then you automatically take x number of exposures for as long as you are comfortable with. I limit myself to 3 minute exposures because my mount does not track as accurately as I'd like but with a good mount and automatic guiding 10 minte exposures are easily possible. A few hours of 10 minute exposures will capture huge amounts of data (in RAW format) and you may need to collect that data over a few days but you'll end up with a lot of data capture from one faint, astronomical object from which you'll get one image. There's no cheating, no faking just time and more than a little cash.

[Mr. Dazzle]

The photo is a fake in that the colors are artificially adjusted/boosted based on the emissions of various elements. Red for hydrogen i can remember, the rest I don't recall. I.e. those colours aren't what you'd see with the naked eye, if you were able to get that view at all. Its a composite image of lots of artificially adjusted/massaged/call it what you will parts.

Amateurs can do the same thing for sure, but its not a "real" image you could ever actually see assuming you could somehow stand in the right spot of deep space.

My point is, I'm sure "they" will do exactly the same sort of compositing with the JWST pics. By way of example, here's that very same patch of sky in IR "finagled" into something we can see side by side.

[Yambo]

The photo is a fake in that the colors are artificially adjusted/boosted based on the emissions of various elements. Red for hydrogen i can remember, the rest I don't recall. I.e. those colours aren't what you'd see with the naked eye, if you were able to get that view at all. Its a composite image of lots of artificially adjusted/massaged/call it what you will parts.

You are right, of course. And all photographs that you have ever taken or seen are fakes. Take a dozen images of the exact same scene changing aperture, ISO or shutter speed between each shot and you'll have a dozen fakes - they'll all differ in one way or another and none of them will be the same as you see the same scene. . Ergo, fakes.

Black and white photos? Fakes. What you see as opposed to what your wife sees? Fakes.

Any photograph that has been anywhere near post processing software? Absolute fake.

Photography is subjective. Post processing can be used to clean up 'dirty' images, remove red eye from portraits (red eye is most definitely fake) and enhance parts of the photograph to the viewers taste. This is exactly what is done with astrophotography. What you see with the naked eye is limited to the visible spectrum (you could call it fake but it is simply limited). Our ability to record the image is severly limited but photographic equipment records extremely well but it too is limited by the chip it contains. A colour camera has effectively a screen above its pixels that is basically a RGGB filter. RGGB because that most closely matches what the eye sees. Take a photograph of a nebula a few hundred light years away and you'll see what the eye sees albeit the eye might need some assistance - a telescope for example. But the camera is recording everything that is there, capturing al those little photons that have travelled across space and time to be captured by a silicon chip. Some of the things it captures cannot be seen with the naked eye but they are there.

Post processing allows the photographer to show that those elements are there and that is done by stretching the image and enhancing colours, luminosity or whatever the software allows. Nothing is added, nothing needs to be added although for some photographs it may be more pleasing to the viewer if some stars are removed or dimmed. This fakery is done because photography is subjective. Some colours may be enhanced, others reduced in intensity because it's what pleases the photographer. Different elements can be shown in different colours which is clearly fake but it is done to highlight the elements that are there and sending photons your way - that you can see or record. So yes it's all fake except what is actually there. Here on earth, we could be sitting in a nebula that is only visible from a few hundred light years away. The particles that the distant observer can see as a nebula are so far apart that we cannot see them. They might be there though.

Amateurs can do the same thing for sure, but its not a "real" image you could ever actually see assuming you could somehow stand in the right spot of deep space.

There is no such thing as a real image, but you can see 'it' and other deep space objects with the naked eye (the Orion nebula for example) and see it or them better with a telescope. You won't see it or them in their full glory though because our eyes, even with the help of a telescope are 'limited'. Taking a 1/100 of a second photograph of the Eagle nebula will show you nothing, but a 3 minute test exposure will show you enough to ensure you are on target. Take 240 x 3 minute exposures of the exact same bit of sky, a load of calibration frames and then process that mass of data from those lovely little photons and you may get a good enough image of the Eagle nebula and be able to see the 'pillars of creation'.

Use a monochrome camera and take a load of exposures with red, green and blue filters, another shed load of photos with Ha, OIII and SII filters, maybe all taken with a light pollution filter because you have a street light nearby or the moon is hanging around and you'll get better data that you can 'fake' into an image in post processing. Or expose what is actually there but the eye/brain cannot see.

My point is, I'm sure "they" will do exactly the same sort of compositing with the JWST pics. By way of example, here's that very same patch of sky in IR "finagled" into something we can see side by side.

I don't think they will do the same sort of compositing with the JWST. I think they have a specific set of goals which don't include amazing the general public.

Which of those two images is fake? Clearly the one on the left shows huge amounts of cosmic dust from which stars are being formed - is that fakery? The IR view ignores that dust - does that mean it isn't actually there?

Take a look at this page and you can see that there are lots of different ways of showing the Eagle nebula, depending on equipment, bias or whatever you will but none of them are fake.

https://www.skyatnightmagazine.com/astr ... le-nebula/