APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Comments and questions about the APOD on the main view screen.
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APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by APOD Robot » Mon May 26, 2014 4:10 am

Image An ALMA Telescope Array Time-Lapse

Explanation: It is the most expensive and complex ground-based astronomy project ever -- what will it see tonight? The Atacama Large Millimeter Array (ALMA) project consists of 66 dishes, many the size of a small house, situated in the high altitude Atacama Desert in Northern Chile. Together, ALMA observes the skies in high-frequency radio light, a band usually used only for local communication due to considerable absorption by humid air. The thin atmosphere and low humidity above ALMA, however, enable it to see deep into our universe in new and unique ways that allow, for example, explorations of the early universe for chemicals involved in star formation, and observing local star systems for signs of disks that form planets. The above time-lapse video shows the course of four ALMA antennas over one night. The Moon sets early in the video, while three dishes repoint in unison. Background stars continually rotate up, the central band of our Milky Way Galaxy pivots around and eventually exits off to the right, while halfway through the Small and Large Magellanic Clouds -- satellite galaxies near our Milky Way -- rise up from below the horizon. Car headlights momentarily illuminate the dishes, while an occasional Earth-orbiting satellite crosses overhead. Daylight ends the video but not ALMA observations -- which typically run both all night and all day.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Beyond » Mon May 26, 2014 4:45 am

I thought I was going to see a time lapse of what ALMA sees, but instead it's a time lapse of a few of the telescopes movements that make up the Array. Oh well.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by owlice » Mon May 26, 2014 6:00 am

You didn't notice the sky in the video, Beyond?
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by wroberts@spamcop.net » Mon May 26, 2014 6:33 am

What happened at 32 seconds? I see what apears to be a meteor strike just to the left of the leftost antenna mount.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Beyond » Mon May 26, 2014 8:16 am

owlice wrote:You didn't notice the sky in the video, Beyond?
That's just watching ALMA watching, not seeing what ALMA sees, oh sharp eyed feathery one.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by tehanu » Mon May 26, 2014 9:33 am

I enjoy the way it feels like the earth turning, more than the stars rotating! Thanks! :ssmile:

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Time-Lapse - a lapse at APOD

Post by Faye Kane♀girl brain » Mon May 26, 2014 9:39 am

Beyond wrote:I thought I was going to see a time lapse of what ALMA sees, but instead it's a time lapse of a few of the telescopes movements that make up the Array. Oh well.
I agree; pretty but boring. Would be cool if I hadn't seen dozens of other time lapse vids of the night sky.

BTW, why aren't the telescopes tracking an object? All three antennae slew in unison, then sit there unmoving while the sky revolves over them.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by RedFishBlueFish » Mon May 26, 2014 11:37 am

Interesting in general, and as I am just getting into time-lapse photography, to me in particular.

Watching the telescopes mysteriously point about, with the sky wheeling majestically behind them, was completely engrossing.

The soundtrack adds nothing but distraction. Something Baroque or New Age may have worked, but not every video needs audio - this being one that did not.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by RedFishBlueFish » Mon May 26, 2014 11:58 am

tehanu wrote:I enjoy the way it feels like the earth turning, more than the stars rotating! Thanks! :ssmile:
Yes. That is quite the illusion is it not.

According to a recent international poll, 25% of Americans are aware of this illusion, and know that the stars do actually move around the stationary earth (as decreed by infallible Pope Paul V in 1616 at the conclusion of Galileo Galilei's inquisition).

Don't have time to look up the poll, so do not recall which of the major polling companies conducted it. I did read the report of it though within the last two months in either Free Inquiry, or in Sceptical Inquirer.

Another finding from the poll: ~75% of Americans (and of Europeans) believe that all radiation is harmful and that it is created only by human technology. GMO plants also came in for a lashing.

My take: Be happy with the telescopes we have now, for there may not be many built in the future.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by southern cross » Mon May 26, 2014 12:41 pm

Another APOD I can't see - presumably because it is a video file format ? :(

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by dbooksta » Mon May 26, 2014 2:10 pm

The telescopes seem to spend a lot of time pointed at lower angles. Wouldn't that increase atmospheric interference? Why not leave those observations to arrays in geographic locations where the observations could be made at higher angles (and hence through less atmosphere)?

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by geckzilla » Mon May 26, 2014 2:14 pm

RedFishBlueFish wrote: According to a recent international poll, 25% of Americans are aware of this illusion, and know that the stars do actually move around the stationary earth (as decreed by infallible Pope Paul V in 1616 at the conclusion of Galileo Galilei's inquisition).

Don't have time to look up the poll, so do not recall which of the major polling companies conducted it. I did read the report of it though within the last two months in either Free Inquiry, or in Sceptical Inquirer.
Oh come on, I don't believe this even for a second. People are ignorant, but not that ignorant. Even the Catholic church officially gave up that notion a long time ago. Either you aren't remembering it correctly or the question was confusing enough for them to answer it incorrectly.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by geckzilla » Mon May 26, 2014 2:18 pm

southern cross wrote:Another APOD I can't see - presumably because it is a video file format ? :(
It is a video, yes. Is YouTube blocked by The Great Firewall? :(
Last edited by geckzilla on Mon May 26, 2014 7:27 pm, edited 1 time in total.
Reason: wrote Vimeo, meant to write YouTube
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Re: Time-Lapse - a lapse at APOD

Post by ShaileshS » Mon May 26, 2014 3:00 pm

Faye Kane♀girl brain wrote:
Beyond wrote:I thought I was going to see a time lapse of what ALMA sees, but instead it's a time lapse of a few of the telescopes movements that make up the Array. Oh well.
I agree; pretty but boring. Would be cool if I hadn't seen dozens of other time lapse vids of the night sky.

BTW, why aren't the telescopes tracking an object? All three antennae slew in unison, then sit there unmoving while the sky revolves over them.

-faye kane
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I totally agree. Video shows nothing different than what we have seen in 100s of such. And, it's so short. I also thought we would see what the telescopes are seeing. Too bad ! And, what's up with the mysterious background music ? As if there's going to be something happening soon, we anticipate and nothing happens. Come on APOD !

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Chris Peterson » Mon May 26, 2014 3:09 pm

geckzilla wrote:Oh come on, I don't believe this even for a second. People are ignorant, but not that ignorant. Even the Catholic church officially gave up that notion a long time ago. Either you aren't remembering it correctly or the question was confusing enough for them to answer it incorrectly.
The numbers are accurate. I've seen the same polls. I do think you're close to the explanation, however. It isn't that very many people are actually geocentrists, but they have such a poor grasp of what things look like that they can't competently answer questions about rotation and revolution and different frames of reference.
Chris

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Re: Time-Lapse - a lapse at APOD

Post by Chris Peterson » Mon May 26, 2014 3:15 pm

Faye Kane♀girl brain wrote:BTW, why aren't the telescopes tracking an object? All three antennae slew in unison, then sit there unmoving while the sky revolves over them.
Watch closely and you'll see that in some cases they are tracking the sky. I expect it depends on the observing program. Sometimes radio telescopes are kept stationary and the data is collected by allowing the sky to track past them, sometimes individual objects are tracked. Both approaches seem to be used during this time lapse. Also, there are probably intervals between data collection where the telescopes are pointed but not operating.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Chris Peterson » Mon May 26, 2014 3:22 pm

dbooksta wrote:The telescopes seem to spend a lot of time pointed at lower angles. Wouldn't that increase atmospheric interference? Why not leave those observations to arrays in geographic locations where the observations could be made at higher angles (and hence through less atmosphere)?
There aren't any other large arrays of submillimeter telescopes, and just a few much smaller submillimeter observatories.

It looks to me like the observations encompass a range of altitudes, from low to high. While the atmospheric attenuation is certainly higher at low altitudes, that doesn't preclude doing good science.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Ann » Mon May 26, 2014 3:23 pm

RedFishBlueFish wrote:
tehanu wrote:I enjoy the way it feels like the earth turning, more than the stars rotating! Thanks! :ssmile:
Yes. That is quite the illusion is it not.

According to a recent international poll, 25% of Americans are aware of this illusion, and know that the stars do actually move around the stationary earth (as decreed by infallible Pope Paul V in 1616 at the conclusion of Galileo Galilei's inquisition).
Yes, sigh. I was trying to teach some of my really not so bright students about Copernicus. "He said something about the solar system that would have shocked most people at that time if they had paid attention, what do you think it was?" I asked them. "That the earth is round?" they answered, hopefully. "No, most scholars at that time already knew that," I replied. "No, Copernicus claimed that the Earth moves around the Sun, not the other way round." My students gave me blank, uncomprehending stares. The idea that the Earth moves around the Sun seemed to be quite new to them.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Chris Peterson » Mon May 26, 2014 3:24 pm

southern cross wrote:Another APOD I can't see - presumably because it is a video file format ? :(
It's an absolutely conventional YouTube video, offered both in Flash and HTML5 formats. No special software required, nothing that isn't absolutely standard. If you can't see it, you are operating in a computer environment that is severely limiting you in ways that go far beyond the occasional unviewable APOD. Probably ought to fix that.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by LocalColor » Mon May 26, 2014 3:27 pm

Enjoyed the video, even tho we have seen many time lapse night sky videos, this one was unique. Imagining what the group of 3 is "listening" to. (And wondering if #4 is also busy?)

We have also seen the polls showing that our fellow Americans are either ignorant of astronomy or its not important to them. (Unfortunately this also impacts science and the future of their children.)

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by owlice » Mon May 26, 2014 3:54 pm

Chris Peterson wrote:
southern cross wrote:Another APOD I can't see - presumably because it is a video file format ? :(
It's an absolutely conventional YouTube video, offered both in Flash and HTML5 formats. No special software required, nothing that isn't absolutely standard. If you can't see it, you are operating in a computer environment that is severely limiting you in ways that go far beyond the occasional unviewable APOD. Probably ought to fix that.
Chris, he's in China. Yes, the computer environment there is severely limiting, and since he works there, it's a little hard for him to do anything about the environment.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Chris Peterson » Mon May 26, 2014 3:57 pm

owlice wrote:Chris, he's in China. Yes, the computer environment there is severely limiting, and since he works there, it's a little hard for him to do anything about the environment.
True enough.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Alexander Thesoso » Mon May 26, 2014 4:09 pm

What is wrong with this picture? Or... What is wrong with me?
I get a disturbing illusion that the stars are moving with respect to each other.
It isn't flicker. It surely isn't that the stars are changing position.

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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Chris Peterson » Mon May 26, 2014 4:13 pm

Alexander Thesoso wrote:What is wrong with this picture? Or... What is wrong with me?
I get a disturbing illusion that the stars are moving with respect to each other.
It isn't flicker. It surely isn't that the stars are changing position.
An optical illusion. Part caused, I think, by video compression and the resizing of the original, and part caused by projection artifacts created by the wide angle lens.
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Re: APOD: An ALMA Telescope Array Time-Lapse (2014 May 26)

Post by Boomer12k » Mon May 26, 2014 7:15 pm

Neat!

I have RARELY seen the galaxy go 90 degrees to the horizon. Nor have I really noticed how close the Small and Large Magellanic Clouds are.

There also seems to be some "GLOW" to the atmosphere.

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