SALT Telescope First Light

carnun writes "On the 1st of September, 5 years after ground breaking, the SALT Telescope released their first light images to the public. Yesterday one of these images was even displayed on NASA's Astronomy Picture of the Day website. The Southern African Large Telescope, built in South Africa, is the largest telescope in the Southern Hemisphere and (depending on how you define it) the equal largest telescope in the world, but built at a budget of only $30 million, about a tenth cheaper than its nearest competitor. The official opening of the telescope is scheduled for the 10th of November, but scientific observations are already a regular occurence. (Disclaimer: I'm the software engineer responsible for the main telescope server.)" Perhaps as an added bonus carnun could even be persuaded to participate heavily in the discussion. Either way, sounds like a cool project to be a part of.

Comments

Impressive Telescope!

[Nerd Systems]

I read some of the details about this, and saw that this telescope can pick up light as small as a candlepower on the moon's surface. That is a pretty impressive light-gathering ability if I have ever seen one... not even the night vision goggles that the military uses has that good of light-gathering. That is a pretty impressive ability to gather light that dim, which is very valuable on a telescope, being able to pick out the faintest of galaxies very far away, as well as seeing the effects that black holes and the like, can have on galaxies in the very distant reaches of space.

It is amazing how good optics are becoming these days... which doesn't just apply to astronomy, bu can also be applied in other areas... areas that can affect all of us one day, and not just for space exploration. So many technologies that have been honed in the space program, have found their way to our use as public citizens. This is a wonderful thing for all of mankind.

Imagine the technologies that are honed with this project being released to the mainstream public down the road... such concepts as more efficient fiber-optics, with light beams being no longer needing fibers to travel across large distances, but simply having a transmitter and receiver on each end, using such optics as this telescope uses, and not being bothered by fiber cuts and the like...

Astronomy is a wonderful hobby, but at the same time, so many things can be contrived from designing technology to see the heavens... which can help out mankind in ways that we have yet to dream of...

As a sidenote, this server seems very slow, so for those trying to check things out, and not able to see anything as a result of the slashdot effect that I am sure is cripping these servers, check back at a later time to see some wonderful images that this telescope has presented to scientists. Astronomy has always been a wonderful hobby and very valuable scientific tool to the science community.

Re:Impressive Telescope!

[Anonymous Coward]

not even the night vision goggles that the military uses has that good of light-gathering

Omg, hand-sized gadget can't gather as much light as a huge complex worth tens of millions. How impressing!

Re:Impressive Telescope!

[LiquidCoooled]

Imagine the technologies that are honed with this project being released to the mainstream public down the road

Paparazzi camera lenses that can snapshot celebrities indiscretions from another continent?

Re:Impressive Telescope!

[CubicleView]

I haven't been able to get to the site so I'm writing this based on my understanding of regular telescopes. Which can gather lots of light mostly because they're huge. You simply cannot get this kind of light gathering ability in a hand held device, they're too small.

Re:Impressive Telescope!

[whimdot]

If this thing can pick up the light of a candle burning on the moon's surface, then someone has been lying to us big time.

Obligatory question about the server

[Inigo Soto]

I'll let carnun guess it :)

Re:Obligatory question about the server

[Soko]

From TFA: (Disclaimer: I'm the software engineer responsible for the main telescope server.)

My guess is that carnun has a very pissed off webserver admin grabbing him by the collar about now.

WebAdmin: W H A T_T H E_F U C K_W E R E_Y O U_T H I K I N G !!!!
carnun: Heh. Sorry 'bout that...
WebAdmin: *produces diamond encrusted LART* AUUUUUGGGGHHHH!!!!
carnun: *SPLUTCH*

Soko

FL

[Anonymous Coward]

First Light!

SALT server supernovas

[Mathinker]

In other news, an enormous emission of light and radiation is observed from SA as SALT's servers get slashdotted...

Re:SALT server supernovas

[Amadodd]

And in all likelyhood the whole of SA gets slashdotted as well. Seriously - for a South African it is very irresponsible to put up large image files that every nerd wants to see and then link them from Slahdot.

Re:SALT server supernovas

[DigitumDei]

Site seems to be holding up. I guess having some of the slowest international bandwidth in the world helps sometimes.

Though I doubt many people outside of SA are going to be able to access it.

I remember when Nixon talked about SALT

[ReformedExCon]

As I recall, even back in the early 1970s, SALT was one of the key planks of Nixon's presidential strategy. I was under the impression that SALT succeeded and was only finally done away with when GWB took office, but to see that it is still working is very cool.

Re:I remember when Nixon talked about SALT

[flubbergust]

Uhm, that was the Strategic Arms Limitation Talks. I guess they perhaps could use this telescope to see if little green men on Mars have nuclear weapons. I dont think it would matter to Bush anyway. USA already declared they will "invade" Mars.

Re:I remember when Nixon talked about SALT

[MaynardJanKeymeulen]

You're either quite funny or extremely stupid.

Depending on how we define what?

[Greeger]

It is the equal largest telescope in the world depending on what measurement? Height? Width? Resolution? I don't like it when news stories use those kinds of boasts because they are so vague. For all we know that could mean that the telescope has the same number of people working for them as the other large telescope.

Re:Depending on how we define what?

[Anonymous Coward]

Large telescopes are always compared by the diameter of their main mirror (or what would be the equivalent diameter in case of a more complicated design).

Re:Depending on how we define what?

[gilzreid]

It is based on the diameter of the primary mirror (~10m for SALT). The equal is the prototype which SALT is based on, the HET in Texas (I think). Resolution depends on diameter so it would also have the best resolution, but the Earth's atmosphere tends to distort things too much. This is why the Hubble Space Telescope (which is a mere 2.4M) is so valuable - no atmospheric disturbance.
However, having a giant mirror means that the telescope can observe faint objects in less time than anything in space at the moment, so can take much higher resolution spectra.

The actual telescope can't use the whole mirror at once because of the design. The telescope only moves in azimuth, which saves a huge amount of cost but means that only a small part of the mirror is used at any one time. As the target rotates around the sky the area on the telescope moves across the mirror to allow longer exposures.

SALT also has very high sensitivity to short wavelengths (blue/UV) which is probably the best of any large telescope, or at least close.

Re:Depending on how we define what?

[katana]

Usually comparisons are based on mirror diameters, so SALT is roughly equal to Keck One or Two, the 10m mirrors on Hawaii. But if you're looking for sharpness of image, then you might be more interested in baselines, where interferometry allows configuration of multiple mirrors to achieve sharper images (by cancelling out interference and unwanted signals), such as the VLT in Chile. Baselines at the VLT can reach 200m, which makes the 10m mirror not quite as impressive.

To put it in slashdot-friendly terms, you shouldn't just compare processors based on clock speed, because different processors may be optimized for different purposes. Mirror size is kind of like clock speed.

Slashdotted

[Jarnis]

I wonder if the telescope could see the smoldering ruins of the webserver from the surface of the moon - as the server just got slashdotted off the face of the earth...

1/10th cheaper?

[Anonymous Coward]

Well, i don't think one tenth is _that_ impressive. Are they sure it's not 10 times cheaper or something?

Re:1/10th cheaper?

[Tomfrh]

It's not correct to say "ten times cheaper" either. Once should say "one tenth the price" or something like that.

Mirror

[Max von H.]

Check the MirrorDot page, the original server is already smoking...

Cost-saving measures

[mirni]

about a tenth cheaper than its nearest competitor
----

Definition of 'nearest competitor' aside, I'd be very interested to know in what ways savings of such magnitude were realised. Cheap labour shouldn't account for much, here.

-m-

Re:Cost-saving measures

[Tomfrh]

I suspects that the writer doesn't know how to write all that good.

Re:Cost-saving measures

[carnun]

One of the big reasons is that SALT's primary mirror is spherical. This means that each of the segments are of exactly the same design. A parabolic mirror, like that used on most other telescopes you general have to have different design for many of the segments. Downside - spherical mirror bring aberations. Upside - they can be compensated for quite by secondary mirrors.

The SALT primary consists of 91 segments each of which cost $30000, compare this to the estimated cost of having a single 10m primary ~$1 000 000 000.

Cheap (but highly skilled) engineers do help and then the last contributing factor is that the mirror is fixed in elevation - spherical mirrors mean that this the telescope is not limited to fixed elevation though.

flame on the moon

[Anonymous Coward]

SALT can detect objects as faint as a candle flame on the moon.

Now, granted I haven't been to the moon myself but I would tend to think a candle flame there would indeed be extremely faint..

OMG... nerdy poetry!.. :)

[Anonymous Coward]

Did you read the nerd factor 10 poetry on the page? For the ones who can not reach the page:


praise poem of the
Southern African Large Telescope

"At the mountain's top I reach up,
I fill my haversack with stars."
- Tatamkhulu Afrika: Nightrider

when the sun sets
we stand in the failing light
stretch our arms,
catch the falling drops.

Medupe & Marang cup our CCD,
save all falling photons,
deepening into a pool of light
whose surface reflects:

stretch marks from the birth of time
hints of gravity's lenses
the pulse of stars
& mating dance of binary suns;

galaxies digitalized - a heaven
captured in butterfly nets of circuitry
red on the readout, disked for storage:
mysteries, solved and sensuous.

Keith Gottschalk


Emphasis added... :)

So... how long till we see other planets?

[cool_number_9]

I graduated at the Optical Research Group of my university and while I was doing something completely different, a few people were working on nulling interferometry, a technique used to cancel all the light of the star, thereby allowing the light of the surrrounding planets to filtered through. For this to work, you need telescopes at different places. So they actually want to build an array in space or maybe they already did that.

With this high sensitivity of this new telescope, I'm just wondering if an array could be built on earth. Then we can really start looking for nice warm little planets...

Re:So... how long till we see other planets?

[MaynardJanKeymeulen]

You should have paid more attention.
Such telescopes exist.

Re:So... how long till we see other planets?

[nbarriga]

So they actually want to build an array in space

Actually, the cost of building a space telescope is enormous. I think the budget for Hubble was somethink around $US 1 billion , the same as ALMA(http://www.eso.org/projects/alma/) or the VLT(http://www.eso.org/paranal/) even though Hubble is a very small telescope. And since the main problem with surface telescopes( athmosphere's refraction) has been overcome using active optics, i don't think it's necessary to put another space telescope.

Re:So... how long till we see other planets?

[Ihlosi]

I think the budget for Hubble was somethink around $US 1 billion ,

How much is that figure expressed in units of "days of war in Iraq" ? And since the main problem with surface telescopes( athmosphere's refraction)

What about atmospheric absorption of certain wavelengths, earth's rotation during long exposure times, light pollution, dust/scattering in the atmosphere, etc ?

Southern Sky

[RocketRainbow]

Mmm... we're looking at the same stars.

I love my Southern sky. As an Australian, I can't say "I love a sunburnt country", but I love the Magellanic Clouds, the Southern Cross, the Pliades... Looking up is how I know I'm home.

And of course your photos won't show bizarre things like the upside-down-moon!

It's about darn time people started putting more effort into the southern sky. You can just survey for a night and show up interesting things down here!

This telescope

[frinkacheese]

Will pick up a pimple on an astronauts ass..

Obligatory 2001 quote...

[srl100]

"My god, it's full of sta...@~0-tw$%^&e" Hmmm, server must be down.

Bronson Bodies

[GomezAdams]

This is great news for astronomy. I just hope they keep an eye out for the Bronson Bodies with their new toy.

SALT Telescope?

[commodoresloat]

Did they pay for it after getting money from the Automatic ATM Machine? After typing in their PIN Number? I know, I should RTFA the article before posting. I'll STFU up now.

You bastards!

[eugene_roux]

We have a tough enough time getting decent bandwidth down here at the Southern tip of Africa, without you bastards Slashdotting our Telescope and taking our undersea cables with it!

Mutter, mutter, mutter...

Cheap telescope

[photonic]

The nice thing about this telescope is that the whole design is aimed at keeping it cheap. To start with it is almost a direct copy of the Hobby-Eberly telescope, so go there if SALT is slashdotted. Reusing a design of course saves a lot and there will not be a lot of redundant science since HET is located at the northern hemisphere and SALT at the southern. The project has a lot of international partners, but obviously the South African astronomy community is the big winner here.

Then the design of the telescope, this is very uncommon to keep costs down: First of all the telescope cannot cover the whole sky, it has a fixed elevation (something like 40 degrees?) and can only rotate around its vertical axis. This saves of course a lot of mechanics and has as an added benefit that the structure will have a constant sagging due to gravity. The cost you pay is of course a limited view of the sky, but there is plenty to see in the part that is visible.

The second innovation is that the shape of the mirror is not parabolic, as in most telescopes, but spherical. This has two benefits: first, all the mirror segments can be produced with the same curvature, which is cheaper than custom segments as for Keck. Secondly, you can change the elevation of your telescope (over a limited range) without moving the main mirror by rotating the rest of the optics from a point in the center of the sphere (this is possible because of spherical symmetry of the mirror). The downside of the spherical optics is that the optical aberations of the system are more severe than for a parabolic mirror, so you need to add some extra optics to compensate. This is no big problem since HET and SALT are not built for making nice pictures, but primarily for spectroscopy, for which a big light collecting area is more important than the best possible imaging system.

Re:No even the goggles...!

[BJZQ8]

Tube-type first-gen NV was invented by the Germans in WW2. Americans fielded a rudimentary type for a sniper rifle, but it was cumbersome and not useful.

Salties

[HermanAB]

Yeah, there are many meanings to SALT:

In South Africa, a Saltie is an Englishman - since he is standing with one foot in London, the other in Cape Town and his dong in the salt water...

In Australia, a Saltie is a seawater crocodile.

The combination of the two would be very amusing to watch...

Re:Apollo Moon Landings

[Red Flayer]

"Besides, what fool would waste time and resources trying to take "nearby" photos of a place we've already been when the telescope can clearly be put to much more useful scientific endeavors?"

Well, possibly to stimulate public curiosity to garner political support for more publicly funded projects?

In the US, PR stunts are very important to science in terms of getting budget $$. See "NASA" circa 1965-2005. And what a great way for US to garner more support for a Mars invas... um, landing.

Of course, it being a non-USian telescope, perhaps capturing images of the US flag on the moon is not the best way to get public funds for your projects...

404 errors, Here is a better link:

[qualico]

Getting 404 errors on the main page when trying to view the images?
Alternatively, they can be viewed here:

http://www.saao.ac.za/news/salt_light.html

Using, my Celestron 9.25" last night here in the north, sure gives you an appreciation of these images and what bigger light buckets nets you.

Showed my wife M57, (Ring Nebula), for the first time.
Albiet, it was washed and faint, its a worthy experience to see things with your "God's Eye".

Can anyone here, who has toured a large telescope, comment on how the captured images compare to the live views?