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Earth's Radio Telescopes Combining Forces

samzenpus posted more than 5 years ago | from the dark-side-of-the-moon dept.

Space 119

Slatterz writes "I own a basic 70mm telescope, which I'm sure Galileo would have given his right arm for in 1609. In fact, this year marks exactly 400 years since Galileo first pointed a telescope at the skies — discovering the moons of Jupiter and helping to prove that the universe doesn't revolve around us. As a mark of respect, the United Nations has declared 2009 the International Year of Astronomy. Official festivities kick off this week in Paris and, to help start the celebrations, 17 radio telescopes in Australia, Asia, Europe and the Americas will track three quasars using something called "real-time Very Long Baseline Interferometry" — basically creating hi-res images by combining their data to simulate a telescope as large as the Earth. Sounds cool."

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so i guess... (0, Offtopic)

Adolf Hitroll (562418) | more than 5 years ago | (#26464325)

...it's not to save Gazans...

And to kickstart the celebrations (5, Funny)

Anonymous Coward | more than 5 years ago | (#26464341)

the United Nations has declared 2009 the International Year of Astronomy. Official festivities kick off this week in Paris and, to help start the celebrations ... a giant light display and a firework!

Re:And to kickstart the celebrations (1)

4D6963 (933028) | more than 5 years ago | (#26464391)

a firework!

"Oh my God, in my telescope, a fast moving bright object! What can it be, is it a meteor, is it a plane?"

*PAAAH*

"Aaah my eye! It's blind!! It's blind!!!"

Re:And to kickstart the celebrations (2, Funny)

Anonymous Coward | more than 5 years ago | (#26464429)

2009: The year of the Astronomy Desktop...

Ups, sorry! ;)

Re:And to kickstart the celebrations (5, Interesting)

CRCulver (715279) | more than 5 years ago | (#26464475)

While growing up, my father imparted something of a passion for astronomy, and I remember being thrilled by a glance through his homebrew Dobsonian reflector. However, light pollution really takes any wonder out of gazing up at the heavens with a naked eye. I've been to some fairly remote places on Earth, such as central Kazakhstan and Western Sahara, but even there local authorities have put up enough lighting to seriously dim the skies. I can't imagine how glorious things must have been a century ago.

It's a pity few even realize what a problem light pollution is. If you want to really appreciate the stars, consider looking at something like Bob Mizon's Light Pollution: Responses and Remedies [amazon.com] . But in the face of apathy from officials, there's no much hope for improvement.

Re:And to kickstart the celebrations (3, Informative)

mbone (558574) | more than 5 years ago | (#26464665)

It's a pity few even realize what a problem light pollution is.

Indeed. Galileo made many of his observations from the city of Venice. Back then, you could still see the stars from a city center. Now, even the outer suburbs are pretty degraded.

If you care about changing this (and a lot can be done), join the International Dark-Sky Association [darksky.org] .

Re:And to kickstart the celebrations (1)

Ngarrang (1023425) | more than 5 years ago | (#26466791)

In October of 2008, I on a motorcycle trip in southeastern Tennessee. That night at the campground was the first I ever saw the Milky Way band in the sky.

I think that is sad that I was 37 years old the first time to see it with my own eyes.

Re:And to kickstart the celebrations (1)

Shakrai (717556) | more than 5 years ago | (#26465025)

I can't imagine how glorious things must have been a century ago.

Well if you have money take your telescope and get out to sea somewhere. There isn't a whole lot of light pollution in the middle of the Pacific or Atlantic.

Re:And to kickstart the celebrations (1)

Tzaq68k (1453485) | more than 5 years ago | (#26465613)

Well if you have money take your telescope and get out to sea somewhere. There isn't a whole lot of light pollution in the middle of the Pacific or Atlantic.

It's quite hard to hold a telescope steady while on a boat.

Re:And to kickstart the celebrations (1)

Shakrai (717556) | more than 5 years ago | (#26465915)

Eh, depends on the boat or ship that you are on but that's a pretty valid point that I hadn't thought of. Still, you'll see more stars with the naked eye or a good set of binoculars than you will with most telescopes on land in light polluted regions.

At sea? (4, Funny)

Civil_Disobedient (261825) | more than 5 years ago | (#26465675)

Well if you have money take your telescope and get out to sea somewhere.

Yeah, and you can bring a grandfather clock to keep time. And if you're bored, you can bring along a Jenga set. Everyone loves boat Jenga.

Re:And to kickstart the celebrations (1)

houghi (78078) | more than 5 years ago | (#26465543)

I am looking at downsides of light pollution.
1) You can not see the stars.
2) ...
I was tempted to add "waste of energy" and there are things to be said for it, yet that is not the downside of light polution, that is the downside of having lights turned on.

So what other downsides are there?

Re:And to kickstart the celebrations (1, Informative)

Anonymous Coward | more than 5 years ago | (#26466329)

There is some evidence to suggest that perpetual light messes with the hormone balance in women, potentially leading to breast cancer.

Re:And to kickstart the celebrations (1)

NeoSkandranon (515696) | more than 5 years ago | (#26466449)

IIRC it potentially messes with animals that use the moon to navigate.

Re:And to kickstart the celebrations (2, Interesting)

wormBait (1358529) | more than 5 years ago | (#26471173)

Depending on where the light pollution is, the effects vary.

2. Some research suggests it messes with people's circadian rhythms (which can lead to insomnia and possible long-term health effects)
3. It can prevent numerous plants from flowering (they think it is always summer)
4. Sea turtles may migrate in the wrong direction when they hatch
5. Predator-prey relations may be skewed
6. Giant mutant spiders that eat all the insects attracted to the lights

Re:And to kickstart the celebrations (2, Funny)

Normal Dan (1053064) | more than 5 years ago | (#26472487)

So what other downsides are there?

I can't cause mischief as easily.

Re:And to kickstart the celebrations (2, Funny)

Luminary Crush (109477) | more than 5 years ago | (#26471319)

...which, of course, would not affect my radio telescope at all. But could you please turn off your phone!

queen would be proud... (1)

georgeda (752150) | more than 5 years ago | (#26464343)

Galileo Galileo figaro!

Re:queen would be proud... (1)

Muad'Dave (255648) | more than 5 years ago | (#26464719)

Magnifico-o-o-o!

Wiki help (4, Informative)

Andr T. (1006215) | more than 5 years ago | (#26464369)

http://en.wikipedia.org/wiki/Radio_astronomy#Very_Long_Baseline_Interferometry [wikipedia.org]

Since the 1970s telescopes from all over the world (and even in Earth orbit) have been combined to perform Very Long Baseline Interferometry. Data received at each antenna is paired with timing information, usually from a local atomic clock, and then stored for later analysis on magnetic tape or hard disk. At that later time, the data is correlated with data from other antennas similarly recorded, to produce the resulting image. Using this method it is possible to synthesise an antenna that is effectively the size of the Earth. The large distances between the telescopes enable very high angular resolutions to be achieved, much greater in fact than in any other field of astronomy. At the highest frequencies, synthesised beams less than 1 milliarcsecond are possible.

Re:Wiki help (1)

conureman (748753) | more than 5 years ago | (#26464423)

The summary made this sound like something that should be already happening. Thanks.

Re:Wiki help (1)

mbone (558574) | more than 5 years ago | (#26464707)

VLBI is 51 years old (it actually started in the late 1960's [nrcan.gc.ca] ) but it is high quality eVLBI that is basically a product of our century (made possible by all of that nice optical fiber criss-crossing our planet).

Re:Wiki help (1)

Sebilrazen (870600) | more than 5 years ago | (#26465115)

VLBI is 51 years old (it actually started in the late 1960's [nrcan.gc.ca] ) but it is high quality eVLBI that is basically a product of our century (made possible by all of that nice optical fiber criss-crossing our planet).

Think about what you typed. VLBI is 51 years old... started in late 1960's. You're sort of right, but it reads wrong.

Let us assume January 1, 1965 is the start of the "late" 1960's (being the latter half). That would give us 2009-1965 = 44. I'm not sure if I suck at math, but from what I can tell 44 != 51.

Did a little reading, the first use of VLBI started in '67, so it's only 42 years old, the technique that led to VLBI, using "closure phase" during interferometric observations, was first demonstrated by Roger Jennison 51 years ago.

Re:Wiki help (1)

mbone (558574) | more than 5 years ago | (#26467937)

Good catch.

VLBI is 41 years old.

(Sorry, too little coffee early in the AM.)

This is called eVLBI (3, Interesting)

mbone (558574) | more than 5 years ago | (#26464403)

This is called eVLBI [evlbi.org] , and it is now done routinely to, e.g., determine the Earth's rotation (UT1).

From a networking standpoint, one interesting thing is that eVLBI requires high bandwidth (1 Gbps is typical), but can tolerate fairly high loss rates (because the actual cross correlation coefficients are rarely as high as 10^-3). This makes it an excellent candidate for an Internet scavenger service [internet2.edu] , where packets are sent at "less than best effort," i.e., with the understanding that they can be dropped if there is any congestion at all, so that eVLBI can use all available bandwidth without choking out other uses. The same technology may prove to be very useful for P2P services [ietf.org] .

Re:This is called eVLBI (2, Insightful)

morgan_greywolf (835522) | more than 5 years ago | (#26464499)

The same technology may prove to be very useful for P2P services [ietf.org].

Indeed. One of the biggest problems with P2P in general is all the congestion it creates by opening so many simultaneous connections. P2P could be much more useful for these kinds of background transfers that are obviously best for scenarios like eLVBI.

With a 'less than best effort' strategy, you'll end up only using the 'extra' or 'leftover' bandwidth and not your whole pipe.

The story the other day about a P2P firewall (which has other more glaringly obvious problems than just being P2P) could make use of this technology as well.

Re:This is called eVLBI (1)

mbone (558574) | more than 5 years ago | (#26471201)

Note that that is "1 Gbps per telescope." It does add up.

Re:This is called eVLBI (1)

Luminary Crush (109477) | more than 5 years ago | (#26471519)

If you look at VLBI [wikipedia.org] it says that it's been used to make "infrared and optical images...". If this technology has applications in the visible light wavelengths is it not possible to array together a large number of optical telescopes similarly?

I understand that timing is the big problem (the light has to assemble in perfect sequence to make it work). Could this be overcome with higher interconnect speeds (eg internet2)?

How long until we have another Seti@Home with amateur optical telescopes?

Re:This is called eVLBI (1)

mbone (558574) | more than 5 years ago | (#26473057)

Not quite. It says "similar techniques have also been used to make infrared and optical images of stellar surfaces"

In the optical, interferometry is done by actually combining light from two or more telescopes [navy.mil] . So, first, the telescopes have to be close enough to do that. Second, the atmosphere limits your coherence between remote sites to 10's or 100's of meters at most (longer separation are possible in the IR than in the optical). Third, the wavelength is much smaller (a factor of ~ 10,000, typically), so source resolution effects (which in the radio start really hurting at an Earth radii or so), start really hurting at a few hundred meters or so. (The sources are typically different (stars versus quasars), but both tend to have sizes around a milli arc second or so.)

The canceled (but hopefully to be revived) SIM mission was an interferometer in space [nasa.gov] , where the atmospheric issues will not obtain, and you could get sufficient accuracy to see the effects of Earth size planets on their stars.

A telescope as large as the Earth (2, Funny)

dimethylxanthine (946092) | more than 5 years ago | (#26464407)

And hopefully they don't screw up the metric/imperial/coordinate whatever units are used across the world and its back and point in the right direction. You wouldn't want to upset Galileo on this date...

Re:A telescope as large as the Earth (1)

ijakings (982830) | more than 5 years ago | (#26464515)

Why? Incase he rises from the grave in zombie rage?

Even so i doubt hed goto all the effort of defying nature and causing zombie havoc for some unit conversion errors. Id of thought the whole light pollution issue would have ticked him off more.

Re:A telescope as large as the Earth (1)

xstonedogx (814876) | more than 5 years ago | (#26464753)

If you were sent to Hell for more almost 350 years just for telling the truth you'd be a little pissed off, too!

Re:A telescope as large as the Earth (3, Interesting)

Cowmonaut (989226) | more than 5 years ago | (#26465039)

What strikes me as funny as if there was/is a God he must have a fantastically disgusting mean streak. Technically it was the Church under the Pope that like burned Gallelio right? The same Church who God supposedly told he would honor the decisions they make down here. So if the Pope condemned Gallelio to hell for telling the truth then he would be there being flayed constantly.

Of course there are other ways you can take that, but since we're talking 100% hypothetical BS I figured I'd be lazy and take the wordings at face value. Alternate beliefs and theories include bits like that "promise" being bullshit by the Church so they can keep power, or God telling lies to people down here and doing whatever He wants up there, etc etc.

Slightly less off topic though I've always wondered what past great scientists would do with modern technology. I blame Star Trek for putting the idea in my head, what with Data and his holodeck friends of Einstein, Freud, Edison and so forth. I wonder if in some cases if these "greats" are only great because they had primitive tools and were more adept at using those and would be considered mediocre if they had modern gear and knew how to use it.

After all, using an IR or Radio telescope is different than using an optical one.

Re:A telescope as large as the Earth (1)

Ihmhi (1206036) | more than 5 years ago | (#26474173)

I wonder if in some cases if these "greats" are only great because they had primitive tools and were more adept at using those and would be considered mediocre if they had modern gear and knew how to use it.

After all, using an IR or Radio telescope is different than using an optical one.

I don't know. A lot of people had some of these tools available to them or the means to make them. I think if we took someone really exceptional from the past and put them in the modern settings, they'd still provide amazing insights.

You said it yourself - they were more adept at using the tools of the time. Who's to say that they wouldn't be more adept at using the tools of *our* time as well after learning how to use them?

Re:A telescope as large as the Earth (2, Funny)

Darby (84953) | more than 5 years ago | (#26475549)

After all, using an IR or Radio telescope is different than using an optical one.

Most of the differences are in how they're built though, and using them is pretty much the same, right?

I mean once they're built, you just point the big end around the sky. With the optical ones you look through the little end, with the radio ones, you put your ear on the little end, and with the IR ones, you put..I dunno, something you want to warm up.... a TV dinner or something on the little end. Astrology isn't so hard.

Re:A telescope as large as the Earth (1)

jstott (212041) | more than 5 years ago | (#26476807)

Technically it was the Church under the Pope that like burned Gallelio right?

Uhh, no.

Head you consulted Wikipedia [wikipedia.org] before posting, you would have seen that Galileo died of natural causes. You're probably thinking of Giordano Bruno [wikipedia.org] , but he was killed because of his theological views, not his scientific views.

What did happen is that Galileo was convected by the Inquisition on a suspicion of heresy (namely, holding heliocentric views even after they were declared contrary to Scripture). He was ordered to renounce his views (which he did) and was also ordered imprisoned (later reduced to house arrest) and his Dialogue Concerning the Two Chief World Systems was placed on the Index of forbidden books.

Of course, in hindsight, publicly ridiculing his then-supporter, Pope Urban VIII, in his Dialogue probably wasn't the best PR move Galileo could have made at that time either...

-JS

Re:A telescope as large as the Earth (1)

Nefarious Wheel (628136) | more than 5 years ago | (#26473801)

If you were sent to Hell for more almost 350 years just for telling the truth you'd be a little pissed off, too!

I'd think Hell would have the better libraries.

Re:A telescope as large as the Earth (2, Interesting)

Shakrai (717556) | more than 5 years ago | (#26465079)

You wouldn't want to upset Galileo on this date...

When I was in Florence I actually got to go see his grave. It's located in the Basilica of Santa Croce. Michelangelo's grave is also located there. They are on opposite ends of the church within sight of each other.

Rumor has it that during one of the many floods that hit Florence the remains of each came up to the surface and they had to guess at who was who when they reburied them. I don't know if this actually true or just something they tell the tourists but I paid my respects to both graves.

If you want ot get in the hobby. (4, Informative)

Lumpy (12016) | more than 5 years ago | (#26464435)

Dont get a crappy scope. it will simply discourage you.

go to orion at http://www.telescope.com/control/main/ [telescope.com] and buy a 8" dobsonian.

you will see things that the guys that have the cheap crap cant.

you will also have a crapload more light gathering than any small lens telescope can hope to have, giving you better star views and even seeing color very well.

http://www.telescope.com/control/product/~category_id=dobsonians/~pcategory=telescopes/~product_id=08943 [telescope.com] is a PERECT beginners telescope. it works fantastic and does not have the crapload of problems and poor viewing that anythign smaller would have.

Also if it can be bought from walmart or radio shack or even elder beerman, it's crap. do not buy it.

I have one of those and the 12" big brother to it. the 8" I loan out all the time to people interested in astronomy and they freak out when they look at saturn and see the rings seperated from the planet unlike a lesser scope can do.

the only drawback is a 8" scope can BLIND YOU if you observe the moon without filters.

Re:If you want ot get in the hobby. (2, Funny)

Anonymous Coward | more than 5 years ago | (#26464575)

Dont get a crappy scope.

you will see things that the guys that have the cheap crap cant.

you will also have a crapload more light gathering

it works fantastic and does not have the crapload of problems and poor viewing that anythign smaller would have.

Also if it can be bought from walmart or radio shack or even elder beerman, it's crap.

You seem to have a "crap" fetish. 2 girls 1 reflector?

Re:If you want ot get in the hobby. (1)

notthepainter (759494) | more than 5 years ago | (#26464585)

And also join your local astronomy club. Very important. You'll learn more that way and have. And if you can't afford the scope, buy some decent 10x50 binoculars. (Garrett Optical makes decent ones and yes, just use the ones you have if you have some. And yes, we could argue the numbers all day, feel free to use any binoculars you want. Google "binocular astronomy" for tips.) Download Stellarium and/or Cartes du Ciel to see what is in the sky.

Aside from light pollution, this is clearly the second golden age of astronomy.

And he was kidding about the moon blinding you w/o filters. ITs brightness is a surprise, but you'll be able to see afterwards.

Re:If you want ot get in the hobby. (1)

Muad'Dave (255648) | more than 5 years ago | (#26464699)

And he was kidding about the moon blinding you w/o filters. ITs brightness is a surprise, but you'll be able to see afterwards.

He may have been kidding, but I thought I had done just that [slashdot.org] .

Re:If you want ot get in the hobby. (3, Informative)

Hoi Polloi (522990) | more than 5 years ago | (#26464617)

the only drawback is a 8" scope can BLIND YOU if you observe the moon without filters.

It didn't blind me when I looked at the moon through the Amherst College 18" refractor [wikipedia.org] but it sure didn't feel good. I had a flashing disk of light in my field of view for about 5 minutes after. I wish the instructor had been a little more aware of the danger.

Re:If you want ot get in the hobby. (1)

mbone (558574) | more than 5 years ago | (#26467975)

He looked at the Sun through his telescope without any filter. It put permanent spots in his vision.

Do not try this at home. In fact, only try this after sunset but before sunrise no matter where you are.

Re:If you want ot get in the hobby. (2, Interesting)

fprintf (82740) | more than 5 years ago | (#26464635)

The price of these telescopes is simply amazing. For a little less than $400 (I assume you have to add shipping and other stuff) you can get http://www.telescope.com/control/product/~category_id=classicdobs/~pcategory=classicdobs/~product_id=08943 [telescope.com] that 8" dobsonian you mentioned. I only went there because of your link and the NOVA/PBS show I watched on home-built astronomy. Basically you can buy a really decent telescope for about the same price as you can build your own, so if just getting started (like I am thinking about) it is easier to buy based on recommendations of active local astronomers.

Thanks for the link. $400 is still a bit out of reach, but we'll see what tax rebate season brings.

Re:If you want ot get in the hobby. (2, Informative)

notthepainter (759494) | more than 5 years ago | (#26464705)

Thanks for the link. $400 is still a bit out of reach, but we'll see what tax rebate season brings.

Buy some decent binoculars or just use the ones you have around the house. You'll start enjoying them now as opposed to waiting until save up the $400. I started with a telescope even though many people recommend binoculars for beginners. I think I use my binoculars now just because it is so easy. Shoot, I've even gone outside between innings of watching the Red Sox on TV! (And yes, I'm aware of dark adaptation.)

You can read about my observing with binoculars at http://notthepainter.com/category/binoculars/ [notthepainter.com] . My goal is to see all of the Messier objects with them.

Re:If you want ot get in the hobby. (1)

meringuoid (568297) | more than 5 years ago | (#26465111)

Buy some decent binoculars or just use the ones you have around the house. You'll start enjoying them now as opposed to waiting until save up the $400.

But be sure to have a tripod for them, or at least something firm to use as a stand. You'll be able to see the four Galilean moons of Jupiter quite easily with a tripod, but you'll struggle to hold the binoculars steadily enough just by hand.

Re:If you want ot get in the hobby. (1)

notthepainter (759494) | more than 5 years ago | (#26465177)

Yes! What he said! I agree! Almost...

A reclining beach chair with arms goes a long way and costs less than binoculars. A long stick can also be used along with the chair to add stability.

I personally use image stabilized binoculars, but these can be expensive.

Re:If you want ot get in the hobby. (1)

Chris Burke (6130) | more than 5 years ago | (#26472903)

You'll be able to see the four Galilean moons of Jupiter quite easily with a tripod, but you'll struggle to hold the binoculars steadily enough just by hand.

Eh, I have no problem seeing the moons just holding the binoculars by hand unless Jupiter is very high in the sky.

A tripod certainly doesn't hurt though.

Re:If you want ot get in the hobby. (1)

Chris Burke (6130) | more than 5 years ago | (#26473089)

My goal is to see all of the Messier objects with them.

That's a cool goal. I've always thought it was really funny how what started as a "List of stuff I don't give a damn about (because they're not comets)" has essentially become "List of cool stuff for an amateur to look at."

Re:If you want ot get in the hobby. (1)

Hoi Polloi (522990) | more than 5 years ago | (#26474405)

Even a good pair of binoculars will show a significant chromatic abberation with the point (or near point) sources of stars and planets. You are still better off investing in a reasonably priced reflector.

Re:If you want ot get in the hobby. (1)

notthepainter (759494) | more than 5 years ago | (#26475749)

Chromatic aberration is highly over rated in my book. Yes, a reflector will have none, that's why I own two. Aside from just looking at the moons of Jupiter, binoculars really aren't made for planets. Nor do I think they are made for individual stars, or even doubles.

When I use mine I'm hunting clusters, open clusters in particular. Or nebula, or galaxies.

I've seen the Helix, the Veil, the North America and the nearby dark nebula Le Gentil 3, I've seen countless galaxies. I've never once cared about chromatic aberration (primarily because these are dim objects so it isn't visibly present.)

The huge advantage of binoculars over any telescope is the quick setup. There is none with image stabilized ones. I just go outside, sit down, turn on my red flashlight and look. It takes me at least half an hour to setup either of my 2 "normal" scopes. With the binoculars I'm often done by then. When I get the telescope out, I'm out there for hours.

Don't get me wrong, I love using my telescopes, especially on the planets. No normal binocular will show you a moon shadow on Jupiter, or the ice caps on Mars, or the Cassinni Division. But almost any astronomer will tell you you need both. And many will tell you to start with binoculars.

Re:If you want ot get in the hobby. (2, Interesting)

Muad'Dave (255648) | more than 5 years ago | (#26464677)

...a[n] 8" scope can BLIND YOU if you observe the moon without filters.

I have to tell a story on myself. I borrowed a 4" telescope from my college, and set out to look at various celestial wonders. Everything was fine until after looking at the moon (and having tried both eyes), I was blind! (Or so I thought). I stumbled into the house, but strangely, I could see. I went back outside, and I couldn't see anything. I finally figured out that the moon's image was bright enough to stimulate my cones and at the same time zap my rods. When I looked away outside, there wasn't enough light for the cones, so I saw nothing. Inside, there was enough light for the cones. I really scared the crap outta myself that time! Scenes from "A Christmas Story" of "You'll burn your eye out, kid" danced through my head.

Re:If you want ot get in the hobby. (0)

Anonymous Coward | more than 5 years ago | (#26476395)

Heh, a condition known as Moon-eye. At my club's observatory on public nights when the moon is out, we generally reserve views of the moon until last in order to preserve the night vision of the participants.

Re:If you want ot get in the hobby. (2, Interesting)

meringuoid (568297) | more than 5 years ago | (#26464977)

I have one of those and the 12" big brother to it. the 8" I loan out all the time to people interested in astronomy and they freak out when they look at saturn and see the rings seperated from the planet unlike a lesser scope can do.

I get a very good view of Saturn with my old 5" Newtonian. Can't make out the Cassini division, but the rings as separate from the planet are perfectly clear.

Re:If you want ot get in the hobby. (1)

laughing_badger (628416) | more than 5 years ago | (#26466755)

the only drawback is a 8" scope can BLIND YOU if you observe the moon without filters.

Do you mean permanent blindness or just an after-image?

if permanent, do you have any kind of citation for that? I'm an astronomer, and I've only ever heard of neutral density filters being needed for comfort, not safety. For the moon - the Sun does of course need suitable filters even with the naked eye.

Observing the moon without filters can be slightly eye-straining through larger scopes, true, and it does cause an after-image which fades in a couple of minutes.

Hmm, google has nothing about viewing the moon blinding people either...

Re:If you want ot get in the hobby. (1)

Muad'Dave (255648) | more than 5 years ago | (#26467447)

As an astronomer, perhaps you could do me a favor. Do you know of a site that predicts conjunctions of Jupiter's Galilean satellites from Earth's perspective? I'd like to know when those four moons are _very_ close together, and preferably not in front of or behind Jupiter as seen from Earth. I know that the inner three are in a binary 1:2:4 rumba, but the fourth one (Callisto) doesn't like to dance.

If nothing else, are the Jupiter-centric Keplerian elements published anywhere? Thank you in advance.

Re:If you want ot get in the hobby. (1)

laughing_badger (628416) | more than 5 years ago | (#26468265)

I don't know of anything that can predict conjunctions like that automatically. I'd probably use one of the planetarium programs like Starry Night to animate the moons in faster that real time and just wait for the appropriate moment.

That would certainly make for a nice photo.

I'll do a little digging to see if I can find a better solution and will post it if I find one.

Re:If you want ot get in the hobby. (1)

mbone (558574) | more than 5 years ago | (#26475563)

Do you know of a site that predicts conjunctions of Jupiter's Galilean satellites from Earth's perspective?

Sky and Telescope has a Javascript utility [skyandtelescope.com] .

JPL's Horizons [nasa.gov] on line system includes major satellites and will also provide orbital elements.

The USNO Nautical almanac also has this information if you want it in print.

Re:If you want ot get in the hobby. (1)

mbone (558574) | more than 5 years ago | (#26475595)

Oh, yes, and Starry Night [starrynightstore.com] will also do this. That might be best if you just want to do amateur astronomy.

I am sure that there are lots of other choices out there, but these are what come to mind right now.

Re:If you want ot get in the hobby. (1)

mbone (558574) | more than 5 years ago | (#26475717)

I'd like to know when those four moons are _very_ close together, and preferably not in front of or behind Jupiter as seen from Earth.

Never. The inner 3 are a Laplace relationship [arxiv.org] , and are never close together. So, among other implications, the arrangement shown at the end of 2001 A Space Odyssey cannot happen.

I highly recommend Murrary and Dermott [amazon.com] if you are interested in the physics of this.

Re:If you want ot get in the hobby. (1)

Muad'Dave (255648) | more than 5 years ago | (#26476627)

Even so, this utility [skyandtelescope.com] shows the inner 3 very close together (although at Jupiter's edge) at 01:49 UT on 1/19/2009. Also, on 1/20/2009 at 07:59 UT all but Io are close together. Remember, I don't care if they're close wrt to each other in space, just along the same line wrt my eye.

Re:If you want ot get in the hobby. (2, Informative)

mbone (558574) | more than 5 years ago | (#26469157)

Dont get a crappy scope. it will simply discourage you.

Yes, it is hard to do VLBI with a telescope that is less than 5 meters in diameter. Also, you will need a good clock. VLBI has been done with Cesium or Rubidium standards, but I would strongly recommend that you pick up one of the excellent Russian masers [qtmrussia.com] . They will easily fit in your garage.

More info for IYA2009 (3, Informative)

MeisterVT (1309831) | more than 5 years ago | (#26464469)

For more information, the website for all of the events in the International Year of Astronomy is here. [astronomy2009.org] It really is amazing what you can see when you get away from light pollution.

Re:More info for IYA2009 (4, Informative)

Bios_Hakr (68586) | more than 5 years ago | (#26464887)

Here are some events to look at this year:

http://www.seasky.org/astronomy/astronomy_calendar_2009.html [seasky.org]

Most can be seen with a simple pair of binoculars. Probably better off with those than with the $100 wal-mart telescope.

And back in the day, there used to be a daily email service with things to look at every night. Unfortunately, I can't find it now...

Re:More info for IYA2009 (2, Informative)

landimal_adurotune (824425) | more than 5 years ago | (#26470421)

The IYA project 365 Days of Astronomy Podcast has been excellent so far as well - for when you are stuck commuting in a light-polluted city this year. http://365daysofastronomy.org/ [365daysofastronomy.org]

Stop calling the man by his first name (3, Funny)

Anonymous Coward | more than 5 years ago | (#26464481)

Have some respect and call him Galilei. Do people say "Albert's theory of relativity"?

Re:Stop calling the man by his first name (0)

Anonymous Coward | more than 5 years ago | (#26464557)

Marv Albert?! I thought his theory was that wearing women's panties is relatively comfortable.

Why? (1)

CarpetShark (865376) | more than 5 years ago | (#26465559)

Why would anyone find a family name more respectful than a personal name? If your name is Joe Brown, and people start referring to your work as done by "one of the browns", it's hardly a personal boost.

Anyway, when people mispronounce your surname, it's definitely going to be unflattering. I can see that happening a lot, with Galilei.

Re:Stop calling the man by his first name (0)

Anonymous Coward | more than 5 years ago | (#26465723)

Uh uh, sure, and let's also start referring to "Buonarotti's painting of the sistine chapel ceiling".

Re:Stop calling the man by his first name (5, Interesting)

buchner.johannes (1139593) | more than 5 years ago | (#26466237)

Interesting.
They [google.com] say:

From: pinkfreud-ga on 30 Mar 2005 10:31 PST

It's quite common for historical figures to be mentioned by their
first names. Rembrandt, Napoleon, Dante, and Leonardo come to mind.

...

From: waukon-ga on 26 May 2005 14:30 PDT

There is a cutoff date (and I forget exactly when, but basically at
the start of the baroque period) where one starts calling European
historical figures by their last names. Michaelangelo Buonorotti is
referred to by his first name, but Michaelangelo Caravaggio is
referred to by his last.

Re:Stop calling the man by his first name (1)

Bastiandantilus (1409389) | more than 5 years ago | (#26473785)

Interesting. They [google.com] say:

From: pinkfreud-ga on 30 Mar 2005 10:31 PST

It's quite common for historical figures to be mentioned by their first names. Rembrandt, Napoleon, Dante, and Leonardo come to mind.

Who says Leonardo unless they are talking about a ninja turtle? Isn't it DaVinci in common usage?

Re:Stop calling the man by his first name (0)

Anonymous Coward | more than 5 years ago | (#26475683)

Wikipedia and its 64 references for one ;-)

Re:Stop calling the man by his first name (1)

rach3l (1453863) | more than 5 years ago | (#26475709)

Do you call Cher "Lapier"? Do you call Madonna "Ciccone"? Whether he intended it or not, Galileo has evolved into a single-name entity (did you ever take science in elementary school?). People using his last name are shallow and pedantic.

My contribution to the (3, Informative)

notthepainter (759494) | more than 5 years ago | (#26464639)

My contribution to the IYA2009 is two fold.

First, I'll be speaking at least twice this year on astronomy to the public. Once at my local library, next week actually on the Winter Constellation, and then again this summer at the local Audubon Society on Binocular Astronomy. Places like these are hungry for smart people like us to talk to the public about our passion.

The second is that I've vowed to get out and do more public observing. This is where you setup your telescope in a busy place, like in a square downtown, and exhort the public to "Come see the Moon!" You can read about one of my adventures last year at http://notthepainter.com/2008/07/come-see-the-moon/ [notthepainter.com] . You can even do outreach to your friends, I've auctioned off star parties at a charity auction, and I brought my telescope to Thanksgiving dinner!

The point is, this is the year that you, the astronomer, should try and make a difference. (Oh, and for those who think you need to be super experienced to do it, you don't, I've been doing this almost 2 years now, hmm, maybe 3, I've been having so much fun I forget.)

If nothing else... (2, Insightful)

east coast (590680) | more than 5 years ago | (#26464643)

It's a good exercise in a co-ordination of this level.

Galileo Thinks Your Gear Sucks (1, Funny)

Ukab the Great (87152) | more than 5 years ago | (#26464687)

"I own a basic 70mm telescope, which I'm sure Galileo would have given his right arm for in 1609.

Considering he gave up his sight to use the dinky little thing he owned, the fact that he'd only give up his right arm doesn't say much about your telescope.

Ninnle has made this possible. (0)

Anonymous Coward | more than 5 years ago | (#26464893)

The radio telescopes are being 'combined' by implementing a network and analysis software running under Ninnle Linux, of course. It's really the only choice they could have made.

Revolving around us? (1)

SrWebDeveloper (1419361) | more than 5 years ago | (#26464913)

Wait... the Universe doesn't revolve around us? Since when? Lord, am I the victim of public education or what. And this Galileo is a MAN?

not higher magnification ? (0)

Anonymous Coward | more than 5 years ago | (#26465357)

By combining you cant get higher magnification because you wont increase amount of photons hitting the sensor.

Compared to an larger reflector which puts more photons and therefor enable us to increase the magnification.

But maybe sensitivity isn't the bottleneck but the clarity, ie better resolution which also is important when zooming in.

principles of syntheic aperture (2, Informative)

peter303 (12292) | more than 5 years ago | (#26466879)

Radio sensors record the full waveform so you can cross-correlate the raw signal to create a large synthetic aperture. Almost all optical telescopes just record intensity without phase, so you cannot synthesize large aperture. A few telescope sites send optical over wave guides for analog correlation. This works for optical telescopes within a few hundred meters of each other.

Re:principles of syntheic aperture (1)

Nyeerrmm (940927) | more than 5 years ago | (#26467605)

While you're absolutely correct, I would point out that you can get some useful data from intensity interferometry in the optical wavelengths. The mechanics of the process means that you get the square magnitude of the mutual coherence, which means a direct reconstruction of an image is impossible. But, this is a problem faced in other areas, particularly x-ray crystallography, so there are ways to reconstruct the image based on some known information about the scene. In imaging a star or planet, you know the background is black and your target is close to circular, etc.

Certainly not as straightforward as radio interferometry, and SNR levels are troublesome, because quantum noise imposes a harsh limit, but its certainly an interesting alternative at any rate.

Re:principles of syntheic aperture (1)

mbone (558574) | more than 5 years ago | (#26471323)

The real trouble with intensity interferometry is that you have only the square root of the sensitivity of phase interferometry, so typically you can only detect the very brightest sources.

The Narrabi [wikipedia.org] intensity interferometer, for example, used 10 meter optical dishes [nasa.gov] IIRC and could only detect the brightest 32 stars, so it was substantially less sensitive to light than the human eye. (Great angular resolution, but very insensitive.)

Re:principles of syntheic aperture (1)

Nyeerrmm (940927) | more than 5 years ago | (#26474153)

Absolutely right, although we have some advantages now that we didn't when the Narrabi experiments were run. First, detectors have improved: higher response speed and higher quantum efficiency do make things easier. This might be able to double the sensitivity at most though (I'd have to find hard data and run numbers, and I need to do other things today).

However, there are some other ways to improve the SNR. By using a splitting up the incoming light into multiple spectral bands and correlating the signals from each band separately, you can increase the SNR by a factor of N_b (number of bands) or sqrt(N_b), I can't recall exactly. Another method (actually what I should be writing about right now for my thesis) is to use multiple telescopes simultaneously to get more baselines, and have a sufficient number of extra measurements than parameters that you want to calculate, and then perform a least squares analysis. This also allows you to find more than stellar radii and limb darkening, since you can include more parameters; none of this could be done at the time of the Narrabri experiments because the computational capability wasn't up to the challenge.

Also, for anyone else reading the thread (I'm sure the parent knows), the 10-meter dishes weren't imaging quality telescopes, since those would be horrendously expensive. They were built of spherical hex-shaped pieces and assembled against a parabolic backing. The original experiments imaging Sirius were actually done with surplus spotlight reflectors. The biggest advantage of intensity interferometers is that they can use crude light buckets and metrology only has to be ~1 cm accurate.

While I'm cautious to be too optimistic about what we can do with new technology applied to intensity interferometers, its definitely worth looking at again.

Re:principles of syntheic aperture (1)

mbone (558574) | more than 5 years ago | (#26475109)

Good post - you raise some points that I have wondered about.

Back when the Narrabi interferometer was in use, even a cooled photomultiplier might have a quantum efficiency of 10 or maybe 20%. Now, with CCDs, 80 % is possible, so that is a factor of 4 or so right there.

BUT, now there are all of these big light buckets looking for Cherenkov radiation from cosmic rays [nasa.gov] , and (as you point out) computer resources are dirt cheap, so the question I would have is, could you do useful "parasitic" observations using, say, Veritas ?

Note, by the way, that the various interplanetary gamma ray burst networks are also intensity interferometers. And, to answer your question, the SNR increases by the sqrt of the bandwidth. If you could do bandwidth synthesis [harvard.edu] , you might be able to really improve your angular precision (not resolution); that is linear in the bandwidth.

Re:principles of syntheic aperture (1)

Nyeerrmm (940927) | more than 5 years ago | (#26475539)

Interesting, thanks for pointing out that article. Bandwidth synthesis actually looks like something I was about to start looking for, although I was hoping to use the varying frequency to induce phase diversity to help with phase-reconstruction methods.

Also, I know there have been a few papers written on using Cherenkov arrays (sorry, don't have my resources with me), although I'm not sure if any have actually been implemented. In the same vein, I've idly wondered if the big mirror-farm style solar plants could be pointed well enough to use. Although I'm guessing the answer is no, but it would be very interesting to be able to use something that large, placing a sensor at the focus of the plant.

Re:principles of syntheic aperture (1)

mbone (558574) | more than 5 years ago | (#26475803)

The optical SETI people are interested in using solar arrays at night [cwru.edu] (as light buckets), and at least some of them can be pointed accurately enough to point at a given star, so I think that the answer to your question is yes. This is discussed further in SETI 2010.

Re:not higher magnification ? (3, Informative)

Nyeerrmm (940927) | more than 5 years ago | (#26467443)

Really, it all comes down to what's known as Fourier optics. In the far field from a distant source, the mutual coherence (cross-correlation) of the light is the 2-D Fourier transform of the original image, through the van Cittert-Zernike theorem. If you're at all familiar with FTs, the components further from the origin correspond to the highest frequencies. So a larger telescope (essentially an analog IFT in this way of thinking, simulating propogating the wave pattern back to the source) is able to cross-correlate the light between the two furthest points on the aperture, allowing you to take into account higher frequency ranges, and get higher resolution.(1)

Therefore, there are two reasons for increasing a telescopes size:
1. You collect more photons, improving signal quality
2. You increase the resolution as you're able to gather more components of the Fourier band. This is limited on Earth due to the seeing effects of the atmosphere, unless you start dealing with adaptive optics.

This kind of work, using multiple apertures to synthesize a much larger one, gets you the second result without much help on the first, but at a much cheaper price. By manually taking the cross-correlations(2), you can get a map of the Fourier field of the image and computationally compute the original image from it.

(1) This is also why blockages over parts of the aperture don't have an obvious effect.
(2) which is why this only works with radio, optical frequencies are much too high to record the actual waveform, so physical beam transmission is necessary over carefully controlled (to 10 nanometers) path lengths.

Re:not higher magnification ? (4, Informative)

mbone (558574) | more than 5 years ago | (#26469275)

Yes, this aperture synthesis is done to increase resolution, not sensitivity. In fact, all known radio sources have a finite size for VLBI (because of the inverse compton effect), and so source brightness starts to decline as baselines go towards two Earth radii. While VLBI has been done from space, if we placed a VLBI antenna on (say) Mars, there would almost certainly be no source visible on Earth-Mars baselines for any obtainable antenna size.

Right Arm or Left Nut? (1)

orkim (238312) | more than 5 years ago | (#26465659)

I RTFA and the summary states he would give his right arm. The article seems to say he would have given his left nut. I'm confused here.

I thought there's not supposed to be conflicting information on the internet.

The real reason for combining telescopes (1)

astrodoom (1396409) | more than 5 years ago | (#26466353)

There are some really hot alien chicks outside our galaxy who tend to leave their blinds open when they change.

Terrible Idea (1)

locallyunscene (1000523) | more than 5 years ago | (#26466917)

I thought it was mandatory for all geeks to watch Ghostbusters? Don't they know the consequences of crossing the streams?

Earth's Radio Telescopes Combining Forces (0)

Muad'Dave (255648) | more than 5 years ago | (#26467219)

Are they going to form Voltron?

Not exactly a planet-sized radio telescope (4, Interesting)

Mal-2 (675116) | more than 5 years ago | (#26468575)

While the resolution of a large array can be similar to one gigantic dish, this does not mean it is as sensitive. No matter how spread the array, it is (at best) only as sensitive as the sum of its individual elements. What is nice though is that as some sites rotate out of the array, others can be brought online, which allows for continuous monitoring of a single patch of space. Even a giant array in the desert like the VLA [nrao.edu] is not capable of performing this feat since it is still just one point as far as the planet is concerned.

Mal-2

Re:Not exactly a planet-sized radio telescope (1)

mbone (558574) | more than 5 years ago | (#26471337)

I beg to differ - it is the size of the planet, it just has some holes in it !

Backyard VLA (1)

plopez (54068) | more than 5 years ago | (#26469195)

Some years ago I ran into a site to combine a large # of backyard radio telescopes into the largest VLA on the planet. I can't find it on the web any more which leads me to believe it didn't work out.

However, it is an interesting idea.

Does any one have a current link or know what happened?

Re:Backyard VLA (1)

mbone (558574) | more than 5 years ago | (#26471417)

Do you mean the GMRT [tifr.res.in] in India ?

It's operational [tifr.res.in] .

Thomas Harriot (0)

Anonymous Coward | more than 5 years ago | (#26473027)

http://news.bbc.co.uk/1/hi/sci/tech/7827732.stm [bbc.co.uk] The BBC reports on the recent findings that earlier and more accurate astronomical maps of planets and moons were created by Thomas Harriot http://en.wikipedia.org/wiki/Thomas_Harriot [wikipedia.org]

So spare a thought for Thomas Harriot, and other such early pioneers, while in admiration of Galileo for this international year of astronomy. There are probably countless others who have paved the way for the love of what they do with little or no acknowledgement

Sure, Galileo gets all the attention and credit! (3, Interesting)

FrenchSilk (847696) | more than 5 years ago | (#26473891)

But Englishman Thomas Harriot made the first drawing of the moon after looking through a telescope several months before Galileo, in July 1609. http://www.space.com/scienceastronomy/090114-first-moon-map.html [space.com]
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