APOD: Four Lasers over Mauna Kea (2014 Jun 23)

[APOD Robot]

Four Lasers over Mauna Kea

Explanation: Are lasers from giant telescopes being used to attack the Galactic center? No. Lasers shot from telescopes are now commonly used to help increase the accuracy of astronomical observations. In some sky locations, Earth atmosphere-induced fluctuations in starlight can indicate how the air mass over a telescope is changing, but many times no bright star exists in the direction where atmospheric information is needed. In these cases, astronomers create an artificial star where they need it -- with a laser. Subsequent observations of the artificial laser guide star can reveal information so detailed about the blurring effects of the Earth's atmosphere that much of this blurring can be removed by rapidly flexing the mirror. Such adaptive optic techniques allow high-resolution ground-based observations of real stars, planets, and nebulae. Pictured above, four telescopes on Mauna Kea, Hawaii, USA are being used simultaneously to study the center of our Galaxy and so all use a laser to create an artificial star nearby.

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[Beyond]

The Four Laseteers in action. All for one, and one for all.

[Nitpicker]

Nice moonbow, too.

[geckzilla]

Curving the wrong direction to be a moonbow. I'd guess some kind of refraction going on in the camera lens.

[Nitpicker]

Curving the wrong direction to be a moonbow. I'd guess some kind of refraction going on in the camera lens.

Yep, that's the sort of observation I only ever seem to make after submitting a post. The Moon was definitely up and to the left at 01:18 on May 20, so I would at least guess it is moonlight causing the aberration.

[geckzilla]

For a brief moment I thought maybe a street lamp could be causing it if the moon wasn't out but then I decided that the possibility of a bunch of astronomers allowing a street lamp to be lit at the top of Mauna Kea is near zero.

[MargaritaMc]

I found today's Apod text hyperlinks very helpful. Thank you to today's editor.

[TheInfinityPoint]

Hi Everyone, yes Geckzilla is correct, it's actually a lens flare from the rising moon off the left side of the frame. It was a waning gibbous so it was quite bright!

[neufer]

Dr. Egon Spengler: There's something very important I forgot to tell you.

Dr. Peter Venkman: What?

Dr. Egon Spengler: Don't cross the streams.

Dr. Peter Venkman: Why?

Dr. Egon Spengler: It would be bad.

Dr. Peter Venkman: I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?

Dr. Egon Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.

Dr Ray Stantz: Total protonic reversal.

Dr. Peter Venkman: Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon.
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---

Dr. Egon Spengler: I have a radical idea. The door swings both ways, we could reverse the particle flow through the gate.

Dr. Peter Venkman: How?

Dr. Egon Spengler: [hesitates] We'll cross the streams.

Dr. Peter Venkman: 'Scuse me Egon? You said crossing the streams was bad!

Dr Ray Stantz: Cross the streams...

Dr. Peter Venkman: You're gonna endanger us, you're gonna endanger our client - the nice lady, who paid us in advance, before she became a dog...

Dr. Egon Spengler: Not necessarily. There's definitely a *very slim* chance we'll survive.

[pause while they consider this]

Dr. Peter Venkman: [slaps Ray] I love this plan! I'm excited to be a part of it! LET'S DO IT!
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[ta152h0]

Dear Earth
take a break from shaking

[stargene1]

Okay... this is obviously a long shot, but it was inspired by the photo of all of the big scopes simultaneously
focused on the same target at the same time. I know that we don't have anything like a decent large scale
optical interferometer in place, either on Earth or in one of the Lagrange points: the gov't won't fund it and
it involves cutting edge tech which we don't really have yet. However, might there be some way to unite
2 or 3 images taken from 2 or 3 large, separated telescopes, aimed simultaneously at the same target,
by computer processing algorithms? Such an approach would not have the profound resolution predicted
for true interferometry and super-wide baselines, but it might yield hi-res results at least.

[Boomer12k]

"Shot through the Heart...and you to blame...DARLIN', you give loooove a BAD NAME...."

They sure do get great results with this technique....I wonder if my Laser PEN can do that....hmmmm. Oh...yeah...OK....my 10" Meade MIRROR won't adjust like that....OK....NEW SCOPE!!!!

:---[===] *

[neufer]

I know that we don't have anything like a decent large scale
optical interferometer in place, either on Earth or in one of the Lagrange points: the gov't won't fund it and
it involves cutting edge tech which we don't really have yet. However, might there be some way to unite
2 or 3 images taken from 2 or 3 large, separated telescopes, aimed simultaneously at the same target,
by computer processing algorithms? Such an approach would not have the profound resolution predicted
for true interferometry and super-wide baselines, but it might yield hi-res results at least.

List of astronomical interferometers at visible and infrared wavelengths.

<<Projects are now beginning that will use interferometers to search for extrasolar planets, either by astrometric measurements of the reflex motion of the star (as used by the Palomar Testbed Interferometer and the VLTI) or through the use of nulling (as will be used by the Keck Interferometer and Darwin).

Impressive results were obtained in the 1990s, with the Mark III measuring diameters of hundreds of stars and many accurate stellar positions, COAST and NPOI producing many very high resolution images, and ISI measuring stars in the mid-infrared for the first time. Additional results included direct measurements of the sizes of and distances to Cepheid variable stars, and young stellar objects. At the beginning of the 21st Century, the VLTI and Keck Interferometer large-telescope arrays came into operation, and the first interferometric measurements of the brightest few extra-galactic targets were performed.

Interferometers are mostly seen by astronomers as very specialized instruments, capable of a very limited range of observations. It is often said that an interferometer achieves the effect of a telescope the size of the distance between the apertures; this is only true in the limited sense of angular resolution. The combined effects of limited aperture area and atmospheric turbulence generally limit interferometers to observations of comparatively bright stars and active galactic nuclei. However, they have proven useful for making very high precision measurements of simple stellar parameters such as size and position (astrometry) and for imaging the nearest giant stars.>>